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Questa tesi si concentra sul lavoro sperimentale nel campo della spettroscopia fondamentale di nanocristalli luminescenti avanzati per applicazioni optoelettroniche, nell'ambito dei materiali per l'energia. In primo luogo, descriverò lo sviluppo di uno strumento per l'analisi avanzata di tali nanoparticelle, ossia la Spettroscopia a Singola Particella (SPS) . Questa tecnica ha il potenziale di analizzare le proprietà ottiche a livello di singolo nanocristallo per comprendere meglio l'influenza della moltitudine di nanodifferenze che si perdono nelle misure di spettroscopia d'insieme; queste informazioni, infatti, diventano sempre più rilevanti man mano che le strategie sintetiche diventano sempre più sofisticate e all'avanguardia. Inoltre, è possibile studiare il processo di antibunching in una potenziale sorgente a singolo emettitore, elemento chiave per lo sviluppo di tecnologie quantistiche. Questo tipo di misura non è mai stato eseguito nel nostro laboratorio, quindi ho iniziato da zero a progettare e mettere insieme l'intero sistema. La realizzazione sperimentale di questo set-up è piuttosto complessa per diversi motivi tra cui il livello di intensità luminosa estremamente basso, la criticità dell'allineamento al di sotto del limite di diffrazione e dei requisiti di risoluzione temporale per le misure di correlazione. Il primo capitolo sarà dedicato allo studio di un progetto efficace e all'ottimizzazione di un set-up SPS, passando attraverso le prove e gli errori che hanno portato alla geometria finale. Siamo riusciti a misurare le proprietà ottiche di nanoplatelets colloidali core-shell a livello di singola particella, ottenendo risultati interessanti e dimostrando l'efficacia del set-up costruito. Parallelamente alla realizzazione di questo set-up, il mio lavoro di ricerca si è focalizzato sullo studio fondamentale di alcune nanostrutture dal design innovativo da studiare, in prospettiva, col sistema SPS. Questi nuovi materiali sono stati descritti nel capitolo 2 e nel capitolo 3; in particolare, il capitolo 2 si concentra sui progressi dei già noti nanocristalli di perovskiti di alogenuro di piombo, partendo dalla realizzazione di cristalli estremamente confinati per osservare gli effetti di confinamento quantico fino alla formazione di eterostrutture per la regolazione e il miglioramento delle proprietà ottiche. Tali eterostrutture possono essere sfruttate anche per produrre fasi termodinamicamente non accessibili, sfruttando l'interazione epitassiale diretta tra i reticoli. Infine, nel capitolo 3, verrà discussa una nuova classe di nanomateriali innovativi, privi di atomi di Pb e dunque a bassa tossicità e impatto ambientale, ma con ottime proprietà ottiche come downshifter This thesis focuses on experimental work in the field of fundamental spectroscopy of advanced luminescent nanocrystals for optoelectronic applications, in the wider context of new materials for energy. First, I will describe the development of a powerful tool for the advanced analysis of such nanoparticles, namely Single Particle Spectroscopy (SPS). This technique has the potential to analyze optical properties at the single nanocrystal level to better understand the influence of the multitude of nano-differences that are lost in ensemble spectroscopy measurements; in fact, this information becomes increasingly relevant as synthetic strategies become more sophisticated and state-of-the-art. In addition, it is possible to study the antibunching process in a potential single-emitter source, a key element in the development of quantum technologies. This type of measurement has never been performed in our laboratory, so I started from scratch to design and put together the whole system. The experimental implementation of this set-up is quite complex for several reasons including the extremely low light intensity level, the criticality of the alignment below the diffraction limit and the time resolution requirements for correlation measurements. The first chapter will be devoted to the study of an effective design and optimization of an SPS set-up, going through the trials and errors that led to the final geometry. We were able to measure the optical properties of core-shell colloidal nanoplatelets at the single-particle level, obtaining peculiar results and demonstrating the effectiveness of the constructed set-up. Parallel to the construction of this set-up, my research work focused on the fundamental study of some nanostructures with novel designs to be measured prospectively with the SPS system. These new materials have been described in Chapter 2 and Chapter 3; in particular, Chapter 2 focuses on the cutting-edge progress of the already well-known lead halide perovskite nanocrystals, starting from the fabrication of extremely confined crystals to observe quantum confinement effects to the formation of heterostructures for tuning and enhancement of optical properties. Such heterostructures can also be used to produce thermodynamically inaccessible phases by exploiting direct epitaxial interaction between lattices. Finally, in Chapter 3, a new class of nanomaterials will be discussed, whose peculiarity is that they are free of Pb atoms and thus have low toxicity and environmental impact, but excellent optical properties as downshifters.

La spettroscopia nel vicino infrarosso è una tecnica abbastanza sviluppata che continua a dimostrare progressi costanti. Questo grazie agli sviluppi di nuovi spettrometri miniaturizzati d'avanguardia. Questi spettrometri possono generare rapidamente un volume elevato di dati spettrali, richiedendo metodologie avanzate come intelligenza artificiale, big data e deep learning per decifrare il contenuto nascosto di questi dati spettrali. Questa ricerca sperimentale si concentra su uno spettrometro miniaturizzato basato sulla tecnologia MEMS e sulla sua applicazione in vari campi. Dimostriamo che lo sviluppo di modelli NIR può essere impegnativo a seconda del campo applicativo. Mostriamo il caso d'uso di questa tecnologia nell'area di Healhcare e nell'industria (alimentare). Piante e Frutti sono stati oggetto delle nostre ricerche, come il Pothos e l'arancia. Anche le polveri organiche hanno trovato applicazione nella nostra ricerca. Inoltre, estendiamo la nostra ricerca sperimentale sul benessere degli animali, in particolare negli allevamenti di bovini da latte. Abbiamo utilizzato metodologie avanzate in casi d'uso specifici. Abbiamo applicato 1D-CNN per la previsione delle quantità di contenuto di materiali organici in miscele di polvere organica in cui è stato raccolto un volume elevato di dati o un modello VAE per prevedere le condizioni dell'acqua come rilevamento di un'anomalia del benessere della pianta Pothos. Mostriamo l'analisi degli spettri e gli approcci di preelaborazione per rimuovere gli artefatti del segnale. Implementiamo diversi metodi di preelaborazione efficaci: metodi di ridimensionamento, derivate spettrali e il filtro Savitsky Golay. Presentiamo i risultati di diversi metodi di ridimensionamento e trasformazione dei dati utilizzando una rete neurale convoluzionale. Near-infrared spectroscopy is a mature technique continuing to demonstrate steady progress. This is thanks to cutting-edge developments of new handheld spectrometers. These spectrometers can quickly generate a high volume of spectral data, requiring advanced methodologies such as artificial intelligence, big data, and deep learning to decipher the hidden content of the spectral data. This experimental research focuses on a handheld spectrometer based on MEMS technology and its application in various fields. We show that developing NIR models can be challenging upon application. We show the use case of this technology in the healthcare area and the industry (food). Plants and Fruits have been subjected to our research, such as Pothos and orange fruit. Organic powders have also found an application in our research. Furthermore, we extend our experimental research into animal wellness, particularly in dairy cow farms. We used advanced methodologies in specific use cases. We applied 1D-CNN when predicting quantities of content in mixtures of organic powder where a high volume of data was collected or a VAE model to predict water conditions as a health anomaly detection in the Pothos plant. We show spectra analysis and preprocessing approaches to remove signal artifacts. We implement different effective preprocessing methods: scaling methods, spectral derivatives, and the Savitsky Golay filter. We present the results of different data scaling and transformation methods using a convolutional neural network.

Nel campo dei semiconduttori, lo studio delle proprietà spin dipendenti forniscono informazioni fondamentali per la realizzazione di dispositivi che uniscano spin, fotonica ed elettronica. In questi dispositivi l’informazione è codificata nel grado di libertà (DOF) dello spin, sfruttando l’accoppiamento spin-orbita (SOC) tra il momento angolare del fotone e lo spin del portatore. Ho concentrato la mia ricerca sullo studio del SOC con spettroscopia ottica in Si, Ge, Sn e loro leghe. Questi materiali possiedono proprietà promettenti per applicazioni di spintronica, tra cui lunghi tempi di vita e lunghezze di diffusione dello spin. I processi di fabbricazione aprono la strada all’ingegnerizzazione del bandgap e dello strain come DOF addizionali per sintonizzare i fenomeni spin-dipendenti. La spettroscopia ottica permette di superare i problemi delle misure elettriche, come la qualità dei contatti, che impediscono una stima corretta dei parametri cinetici. I pozzi quantici (QW), sono valide piattaforme per unire i DOF sopracitati e permettere la manipolazione dello spin con campi elettrici. Nei sistemi a QW che mancano della simmetria di inversione di punto o di quella strutturale (BIA/SIA), la degenerazione di spin è rimossa dai campi Dresselhaus o Rashba. In quanto campi magnetici, possono agire agiscono sullo spin cambiandone l’orientazione. La SIA può sorgere da un drogaggio asimmetrico. In questo caso, il dispositivo possiede anche un campo elettrico che può essere sfruttato. Infatti, con un campo elettrico esterno si può modulare il campo Rashba, manipolando lo spin. Questa possibilità è significativa per la spintronica, si pensi allo spin-FET, dove la tensione di gate seleziona l’orientazione dello spin e quindi lo stato on/off. Ho eseguito misure di fotoluminescenza (PL) su campioni costituiti da uno stack di 50 QW di Ge/Si0.15Ge0.85 cresciuto nella zona intrinseca di un diodo p-i-n. Il drogaggio asimmetrico introduce la SIA, permettendo di manipolare elettricamente lo spin. Tramite due contatti in Al, ho sintonizzato un campo elettrico esterno e studiato gli effetti sulla popolazione di spin tramite PL. Inoltre, un’analisi in funzione della potenza ha mostrato una dipendenza della polarizzazione della PL dalla pompa ottica. Ho studiato anche una singola modulation-doped QW Ge0.91Sn0.09/Ge. Il profilo di banda confina delle lacune e permette la formazione di un gas bidimensionale di lacune. La struttura asimmetrica introduce la SIA, permettendo di studiare meccanismi di conversione spin-carica. Tramite litografia ho realizzato una barra di Hall ed ho eseguito misure di effetto spin-Hall inverso, da cui ho potuto estrarre l’angolo di spin-Hall. Ho anche compiuto misure magneto-ottiche a 4K, sfruttando l’effetto Hanle, per ottenere il tempo di vita (T) del portatore, che risulta di pochi ns. L’effetto Hanle è stato applicato per la prima volta nei materiali del quarto gruppo in epistrati di Ge1-xSnx (sotto), e l’ho esteso alle QW, dimostrandosi una tecnica affidabile per determinare T. Ho studiato anche campioni di epistrato di Ge1-xSnx. Il contenuto di Sn varia da 0 a 10 %, e lo strain compressivo assicura una natura indiretta del bandgap. Ho estratto T e ho trovato un comportamento non banale al variare della percentuale di Sn, la cui origine può essere attribuita alla presenza di difetti del cristallo. Questi difetti sono dovuti possibilmente alla crescita fortemente fuori equilibrio necessaria per la realizzazione di campioni di Ge1-xSnx ricchi in Sn. Per concludere, in questa tesi mi sono occupato di misure ottiche per indagare il SOC in eterostrutture di materiali del IV gruppo. I risultati ottenuti sono un passo in avanti nell’investigazione della dinamica dello spin elettronico del gruppo IV e aprono la strada verso studi futuri sulla manipolazione elettro-ottica dello spin in tecnologie quantistiche basate sull’interazione spin-luce, come spin-FET, spin-laser In the field of semiconductors, the study of spin-dependent properties provides fundamental information needed for the realization of devices that merge spin, photonic and electronic functionalities. In these devices the information is encoded in the spin degree of freedom (DOF), exploiting the interaction between the angular momentum of the photon and the carrier spin via the spin-orbit coupling (SOC). I focused on the study of SOC in Si, Ge, Sn and their alloys using optical spectroscopy. These materials possess promising properties for spintronics applications such as long spin lifetime, diffusion length and decoherence time. Notably, the advanced manufacture also opens the way to bandgap and strain engineering as further DOF to tune spin-dependent phenomena, whereas the application of optical spectroscopy allows to overcome typical problems of electrical measurements, e.g., the quality of contacts, that hamper the estimation of carrier kinetics parameters Quantum well (QW) systems are valid platforms to merge all the aforementioned DOF and to also introduce a way to manipulate the spin via electric fields. Indeed, in QW systems that possess bulk or structure inversion asymmetry (BIA/SIA), the spin degeneracy is removed due to the Dresselhaus or Rashba fields. As effective magnetic fields, they can act on the spin of a carrier, ultimately changing its orientation. SIA can arise from an asymmetric doping of the device. In this case, the device also possesses an intrinsic electric field, which can be of practical use for applications. Indeed, an external field can be applied to tune the Rashba field, achieving spin manipulation. This opportunity has a strong impact in spintronics devices, such as the spin-FET, where the gate voltage selects the orientation of the spin and switch between on/off states I carried out photoluminescence (PL) investigations on a stack of 50 Ge/Si0.15Ge0.85 QWs grown within the intrinsic region of a p-i-n diode. The asymmetric doping introduces the SIA, necessary for achieving electrical manipulation of the spin. Via a pair of Al contacts, I was also able to study the effect of a tunable external electric field on the spin population via continuous-wave as well as time-resolved PL. Additionally, a power dependent analysis unveiled a strong effect of the light pump on the polarization I also performed PL measurements on a single modulation-doped Ge0.91Sn0.09/Ge QW. The band edge profile confines holes in the well, resulting in the formation of a two-dimensional hole gas. The asymmetric structure introduces the SIA and allows for the observation of spin-to-charge conversion mechanisms in this 2D system. I patterned a Hall bar on the sample and performed inverse spin-Hall effect measurements, extracting the spin-Hall angle. I also performed magneto-optics measurement, namely the Hanle effect, to unveil the carrier lifetime (T) of the material, which is in the ns regime at 10 K. This optical technique was applied for the first time to group IV materials in Ge1-xSnx epilayers (below), and was extended also to the QW system, proving it to be a reliable and easy method to determine T I have also studied Ge1-xSnx epilayers. The Sn content was varied from 0 to 10 %, while the compressive strain ensured an indirect bandgap nature. I applied Hanle effect to extract T and I unveiled a non-trivial behaviour with the Sn content, whose origin is ascribed to the presence of crystal flaws possibly due to the strong out-of-equilibrium growth conditions required for the realization of Sn-rich Ge1-xSnx samples In conclusion, this thesis is devoted to an all-optical investigation of SOC in heterostructures of group IV materials. The results obtained here are a step forwards in the investigation of spin dynamics of electrons in group IV and pave the way to future exploration of electrical-optical manipulation of spins in quantum technologies based on spin-photon interaction such as spin-FETs and spin-lasers

Le mie attività di ricerca hanno indagato i meccanismi di ricombinazione eccitonici in nanocristalli semiconduttori colloidali (NC), promuovendo lo sviluppo di nuovi paradigmi per la manipolazione delle proprietà ottiche e di scintillazione. Grazie all'ampia gamma di tecniche spettroscopiche e alle preziose collaborazioni intraprese, le mie conclusioni sono state pubblicate in prestigiose riviste scientifiche, contribuendo al progresso della comunità di scienziati dei nanomateriali. La mia ricerca ha trattato principalmente due temi di attuale rilevanza tecnologica: i) l'origine della fotoluminescenza in NC di calcogenuri ternari I-III-VI2 Cd-free come CuInS2 e AgInS2 ii) l'impiego di nanostrutture di perovskiti in schemi di rivelazione e/o conversione in energia di radiazione ionizzante. Nello specifico, l’uso di tecniche spettroscopiche complementari in regime di temperatura controllata ha validato la presenza di sottolivelli intrinseci, con diversa parità, nella banda di valenza di NC stechiometrici di CuInS2 responsabili delle proprietà ottiche di questa classe di NC. I miei risultati, supportati da simulazioni di propagazione Monte Carlo, hanno portato alla fabbricazione di un concentratore solare luminescente - con efficienza record - basato su NC di CuInS2 con taglia ottimale. Lo studio è stato quindi esteso a NC di AgInS2, un materiale meno studiato ad oggi, ma molto promettente per applicazioni di bioimaging grazie all’assenza di elementi tossici. Quindi, ho investigato la rivelazione di radiazione ionizzante attraverso nanostrutture ad alto numero atomico come le perovskiti a base di alogenuri di piombo (LHP), ed in particolare il CsPbBr3. Attraverso lo studio dettagliato delle proprietà di foto- e radio-luminescenza, ho evidenziato gli effetti dell’interazione tra eccitone di bordo banda e stati di difetto shallow/deep in nanostrutture di CsPbBr3 con diversa dimensionalità. Questo studio fondamentale ha offerto una piattaforma per sviluppare nuove strategie sintetiche atte a passivare i siti di intrappolamento sulle superfici degli NC che hanno portato ad un incremento di efficienza di scintillazione del 500%. La stabilità dei NC di CsPbBr3 è stata infine verificata in termini di resistenza alla radiazione gammma fino a dosi estreme di 1 MGy. Inoltre, per estendere la loro applicazione alla radiation detection con dispositivi a guida d’onda, ho studiato la sensibilizzazione di un colorante organico accoppiato a NC di CsPbBr3, realizzando il primo esempio di scintillatore plastico con ampio Stokes-shift e luminescenza veloce basato su LHP. Per superare i limiti imposti dalla presenza di Pb nelle LHP, ho infine esplorato le proprietà ottiche e di scintillazione di nuove classi emergenti di perovskiti doppie green. Le informazioni raccolte incoraggiano il proseguimento di questa linea di ricerca indicando la passivazione superficiale come strategia più promettente per raggiungere prestazioni analoghe alle controparti a base di Pb. During my PhD I investigated excitonic recombination mechanisms in colloidal semiconductor nanocrystals (NCs), promoting the development of new paradigms for the manipulation of optical and scintillation properties. Thanks to the wide range of spectroscopic techniques and the valuable collaborations undertaken, my conclusions have been published in prestigious scientific journals, contributing to the advancement of the community of nanomaterials scientists. My research mainly dealt with two topics of current technological importance: i) the origin of photoluminescence in NC of Cd-free ternary I-III-VI2 chalcogenides such as CuInS2 and AgInS2 ii) the use of perovskite nanostructures in detection schemes and/or energy conversion of ionizing radiation. Specifically, the use of complementary spectroscopic techniques in a controlled temperature regime has validated the presence of intrinsic sublevels, with different parity, in the valence band of the stoichiometric CuInS2 NCs responsible for the optical properties of this class of NC. My results, supported by Monte Carlo ray-tracing simulations, led to the fabrication of a luminescent solar concentrator - with record efficiency - based on CuInS2 NCs with optimal size. The study was then extended to AgInS2 NCs, a less investigates material so far, but very promising for bioimaging applications thanks to the absence of toxic elements. Then, I investigated the detection of ionizing radiation through high atomic number nanostructures such as lead halide perovskites (LHP), and in particular CsPbBr3. Through the detailed study of photo- and radio-luminescence properties, I highlighted the effects of the interaction between band edge exciton and shallow/deep defect states in CsPbBr3 nanostructures with different dimensionality. This fundamental study offered a platform to develop novel synthetic strategies to passivate trap sites on NC surfaces that led to a 500% enhancement of scintillation yield. The stability of CsPbBr3 NCs was finally verified in terms of radiation hardness, up to extreme gamma doses of 1 MGy. Furthermore, to extend their application to radiation detection with waveguiding devices, I studied the sensitization of an organic dye coupled to CsPbBr3 NCs, creating the first example of a plastic scintillator with wide Stokes-shift and fast luminescence based on LHP. To overcome the limitations imposed by the presence of Pb in LHPs, I finally explored the optical and scintillation properties of new emerging classes of green double perovskites. The information gathered encourages the continuation of this line of research, indicating surface passivation as the most promising strategy for achieving performance similar to the Pb-based counterparts.

La scoperta di pianeti che orbitano intorno ad altre stelle è uno degli eventi più importanti nell'astrofisica galattica degli ultimi due decenni. Dalla scoperta del primo esopianeta nel 1995, il numero di esopianeti scoperti è cresciuto sempre più in fretta e attualmente conosciamo più di 4,000 pianeti, molto diversi per dimensioni e distanza dalla stella ospite e anche in fattori come temperatura, massa, densità. La diversità degli esopianeti è un fattore chiave per comprendere la formazione dei sistemi planetari e in particolare la formazione del Sistema Solare e del nostro pianeta, la Terra. Questo è il motivo per cui la scienza osservativa degli esopianeti si sta concentrando su due diversi obiettivi: i) la caratterizzazione degli esopianeti, nel tentativo di determinare il raggio, la massa, la densità e la composizione degli oggetti osservati e ii) la caratterizzazione delle loro atmosfere, stabilendo gli elementi che l'atmosfera di un pianeta può supportare e i meccanismi che guidano i processi atmosferici. Caratterizzazione degli Esopianeti La fotometria, con il metodo dei transiti si è rivelato senza dubbio il metodo di scoperta di esopianeti con il maggior successo. La forza di questo metodo è il numero di parametri che possono essere ottenuti osservando il transito dei pianeti, soprattutto in combinazione con le osservazioni di velocità radiale (VR). In questo contesto, uno dei gruppi più prolifici è il Consorzio GTO di HARPS-N, che sfrutta l'alta risoluzione e l'estrema stabilità dello spettrografo HARPS-N, installato al Telescopio Nazionale Galileo, per caratterizzare e scoprire esopianeti combinando il metodo dei transiti e quello delle velocità radiali. Come collaboratore di questo gruppo, ho studiato un pianeta candidato scoperto dalla Campagna 16 della missione K2, HD 80653 b, una super-Terra che transita davanti alla sua stella con un periodo orbitale molto breve, e ho usato le VR HARPS-N per caratterizzarlo, ottenendo la sua massa e definendone la densità. Il pianeta appartiene ad una particolare classe di esopianeti: i pianeti a periodo ultra-corto, oggetti che orbitano intorno alle loro stelle con periodi estremamente brevi, più piccoli di due raggi terrestri e con composizioni simili a quella terrestre. Caratterizzazione di Atmosfere I gioviani ultra-caldi sono laboratori eccellenti per lo studio delle atmosfere esoplanetarie. Il sodio, per la sua grande sezione d'urto e per il fatto che le sue righe spettrali principali si trovano nel range spettrale della maggior parte degli spettrografi, è l'elemento più studiato, ma lo studio di nuove righe spettrali è cominciato. Righe del ferro, del titanio, del magnesio, ma anche tracce di cromo, scandio e ittrio sono state trovate negli spettri di trasmissione ad alta risoluzione dei pianeti più caldi. I due gioviani ultra-caldi KELT-9 b e KELT-20 b sono stati osservati dal programma atmosfere del gruppo italiano Global architecture of Planetary Systems (GAPS). Come membro del gruppo ho potuto esplorare più in dettaglio il metodo della spettroscopia in transito, creando due diverse routine per la caratterizzazione delle atmosfere. Il primo metodo segue approcci già utilizzati in precedenza, ma è in grado di rilevare righe spettrali deboli come quelle del magnesio, sommandole nello spazio delle velocità. Usando questo approccio ho analizzato gli spettri ad alta risoluzione di KELT-9 b e KELT-20 b e ho ottenuto i loro spettri di trasmissione, rilevando un assorbimento significativo per Na, H, Fe e Mg I. Il secondo metodo estrae gli spettri di trasmissione ad alta risoluzione e li cross-correla con modelli teorici di spettri di trasmissione. Analizzando gli spettri di KELT-20 b e utilizzando la cross-correlazione ho potuto confermare la presenza di Fe I, Fe II e Na I, trovate da analisi precedenti di altri gruppi di ricerca. The discovery of planets orbiting around stars other than the Sun is by far the most relevant event in the galactic astrophysics of the last two decades. Since the discovery of the first exoplanet in 1995, the number of exoplanets discovered grew fast and we currently know more than 4,000 exoplanets, very diverse in dimension and distance from parent stars and also in factors as temperature, mass, density. The diversity of exoplanets is a key factor to understand more about the formation of planetary systems and in particular the formation of the Solar System and our planet, the Earth. This is the reason why observational exoplanetary science is currently focusing on two different fields: i) the characterization of exoplanets, trying to determine the radius, the mass, the density and the bulk composition of the objects observed, and ii) the characterization of their atmospheres, establishing the elements that the atmosphere of a planet supports and the mechanisms that drive the atmospheric processes. Characterization of Exoplanets Photometry with the transit method has arguably been the most successful exoplanet discovery method to date. The method’s strength is the rich set of parameters that can be obtained from transiting planets, in particular in combination with RV observations. In this framework, one of the most prolific groups is the HARPS-N Guaranteed Time Observations (GTO) Consortium, that makes use of the high resolution (R = 115,000) and extreme stability of the HARPS-N spectrograph, installed on the Telescopio Nazionale Galileo (TNG), to characterize and discover exoplanets by combining transits and RV methods. As a collaborator of this group, I studied a candidate planet discovered by K2 Campaign 16, HD 80653 b, a super-Earth planet transiting the star on a short period orbit, and used HARPS-N RV data to characterize it, finding its mass and defining its bulk density. It belongs to a peculiar class of exoplanets: the Ultra-Short Period (USP) planets, objects that orbit their stars with extremely short periods, smaller than about 2 Earth Radii and compositions similar to that of the Earth. Characterization of Atmospheres Ultra-hot Jupiters are excellent laboratories for the study of exoplanetary atmospheres. Sodium, due to its large cross-section and to the fact it is in the wavelength range of most optical spectrographs, is the most studied element, but new interesting features begin to be analyzed. Lines of iron, titanium, magnesium, but also chromium, scandium and yttrium have been found in the high resolution transmission spectra of the hottest planets. The two ultra-hot Jupiters KELT-9 b and KELT-20 b were observed in the framework of the Global architecture of Planetary Systems (GAPS) Atmosphere program. I explored more in detail the transit spectroscopy method, creating two different routines for atmosphere characterization. The first routine follows previous approaches for high-resolution spectroscopy, but is able to detect weak spectral lines such as those of magnesium, by co-adding the lines in the velocities space. Using this procedure, I analyzed the high-resolution spectra of KELT-9 b and KELT-20 b, obtaining their transmission spectra and detecting significant absorption for Na, H, Fe and Mg I. The second routine extracts the high-resolution transmission spectra of exoplanets and cross-correlates them with theoretical transmission spectra models. I analyzed the high-resolution spectra of KELT-20 b and with the cross-correlation technique I confirmed previous detections of Fe I, Fe II, and Na I.

I nanocristalli colloidali a semiconduttore (NC), grazie alle loro proprietà ottiche regolabili tramite la dimensione ed alla processabilità in soluzione, sono state a lungo proposte come alternative versatili e sintetizzate chimicamente per numerose tecnologie fotoniche, optoelettroniche e quanto-computazionali, nonché come building-blocks funzionali e superatomici per metamateriali artificiali assemblati con approcci bottom-up. Dalla loro scoperta oltre 30 anni fa, enormi progressi nella chimica colloidale e superficiale, nella fisica dei NC e nelle applicazioni nei dispostivi, hanno portato queste proposte sempre più vicine alla realtà. In questo lavoro esploro i fenomeni fotofisici di quattro diversi sistemi di NC, differenziati dalla composizione chimica e dalla loro forma. Ho studiato i più promettenti NC ternari intrinseci di CuInS2 che in modo innato offrono alternative senza metalli pesanti e non tossiche ai materiali esistenti a base di Cd e Pb, caratterizzate da un ampio Stokes shift e lunghi tempi di decadimento di fotoluminescenza. L’origine di queste proprietà ottiche nei NC di CuInS2 non era però stata compresa, con teorie contrastanti che le descrivono. Qui, dopo aver confermato sperimentalmente l’origine della PL dovuta alla struttura fine della banda di valenza, abbiamo ottimizzato i NC per fabbricare un concentratore solare luminescente ad ampia area (30x30 cm2) con una efficienza di potenza ottica record del 6.8%. In seguito, discuto gli effetti del drogaggio ad impurezza elettronica in NC di calcogenuri binari sintetizzati tramite una innovativa procedura di crescita “a seme” che risulta in un numero preciso di droganti in ogni NC, quindi superando il limite poissoniano per le loro proprietà di semiconduttori magnetici diluiti (DMS). Studi strutturali, spettroscopici e magneto-ottici descrivono in dettaglio i processi fisici coinvolti, dovuti al livello di drogaggio esatto dei NC. Gli atomi d’oro, inseriti come droganti per la prima volta all’interno di NC II-VI, sono incorporati come specie non magnetica Au+ ed attivano una PL intensa e variabile con la dimensione all’interno del gap del semiconduttore, modificando artificialmente l’occupazione della banda di valenza. Fondamentalmente, la conversione transiente degli Au+ in Au2+ paramagnetici (configurazione 5d9) sotto eccitazione ottica genera sia un forte magnetismo che un comportamento da DMS che dimostrano il contributo delle singole impurezze paramagnetiche al magnetismo macroscopico dei NC, sbloccando il loro potenziale applicativo in dispositivi quantici e di spintronica. Inoltre, riporto gli effetti del drogaggio sostituzionale con atomi paramagnetici in NC di perovskite CsPbCl3 drogati con Mn2+ e rivelo il meccanismo di trasferimento di energia specifico che coinvolge stati di difetto poco profondi che risultano nella duplice emissione di PL e inducono uno Stokes shift vantaggioso per tecnologie di gestione fotonica. Infine, concludo mostrando gli effetti della anisotropia di forma in sistemi di NC colloidali con la sintesi e lo studio di nanoplateles bidimensionali di CdTe. Inoltre, mostro alcuni dati spettroscopici preliminari che rendono questi sistemi molto attraenti per applicazioni nella tecnologia laser e di rilevamento di radiazione ultraveloce. Nel corso di questo lavoro, ho lavorato sulla sintesi colloidale delle nanostrutture e studiato i sistemi nanocristallini menzionati usando tecniche di caratterizzazione strutturale come la diffrazione di raggi X e la microscopia a trasmissione elettronica. Tecniche spettroscopiche tra cui l’assorbimento transiente ultraveloce, la PL a stato stazionario e risolta in tempo a temperature criogeniche, il dicroismo circolare magnetico e la risonanza paramagnetica di elettroni sono state usate per investigare queste nanostrutture, chiarendo la loro fotofisica fondamentale e sfruttando i loro potenziali applicativi in tecnologie moderne e di nuova generazione. Colloidal semiconductor nanocrystals (NCs), owing to their size-tuneable electronic properties and solution processability, have long been proposed as versatile chemically synthesized alternatives for many photonic, optoelectronic, and quantum computational technologies as well as super-atomic functional building blocks for bottom-up assembled artificial metamaterials. Since their original discovery over 30 years ago, tremendous advancements in colloidal and surface chemistry, NC physics, and device application have brought this vision closer to reality. In this work I explore these photophysical phenomena in four different NC systems diversified by chemical composition and shapes. I studied the most favorable intrinsic ternary CuInS2 NCs which inherently offers heavy metal free, non-toxic alternatives to the existing Cd and Pb based materials with a large Stokes shift and long photoluminescence decay time. The origin of these optical properties in CuInS2 NCs were however not fully understood with conflicting theories describing its characteristic aforementioned properties. Here, subsequential to experimentally confirming the valence band fine structure origin of luminescence in these nanostructures, we utilized the optimized NCs and fabricated a large area Luminescent solar concentrator of 30ˣ30 cm2 area with record Optical Power Efficiency of 6.8% to the date. Then, I discuss the effects of electronic impurity doping in binary chalcogenide NCs synthesized by a novel seeded growth procedure resulting in quantized dopants in each NC thus overcoming the Poissionian bottleneck for their diluted magnetic semiconductor properties. Structural, spectroscopic, and magneto-optical investigations trace a comprehensive picture of the physical processes involved, resulting from the exact doping level of the NCs. Gold atoms, doped here for the first time through the reaction protocol into II−VI NCs, are found to incorporate as non-magnetic Au+ species activating intense size-tuneable intragap photoluminescence and artificially offsetting the hole occupancy of valence band states. Fundamentally, the transient conversion of Au+ to paramagnetic Au2+ (5d9 configuration) under optical excitation results in strong photoinduced magnetism and diluted magnetic semiconductor behaviour revealing the contribution of individual paramagnetic impurities to the macroscopic magnetism of the NCs unlocking their potential to be exploited for applications in quantum and spintronic devices. Moreover, I communicate the effects of substitutional doping with paramagnetic atoms in Manganese doped CsPbCl3 perovskite NCs and reveal a peculiar energy transfer mechanism involving shallow defects states subsequently resulting in dual emission and inducing Stokes shift desirable for photon management technologies. Finally, I conclude by talking about the effect of shape anisotropy in colloidal NC systems by synthesizing and studying two-dimensional colloidal CdTe nanoplatelets. Moreover, I report some very interesting preliminary spectroscopic data that presents these NC systems at great heed with respect to their application in lasing technology and in Ultrafast radiation detection applications. Through the course of my PhD, I worked on the colloidal synthesis of nanostructures, and studied the aforementioned NC systems using structural characterization techniques like X-Ray diffractions and transmission electron microscopy. Spectroscopic techniques including ultrafast transient absorption, steady state and time resolved photoluminescence spectroscopy at cryogenic temperatures, magnetic circular dichroism and electron paramagnetic resonance were used to study and report these nanostructures, thus elucidating their fundamental photophysics and exploit their applicative potential in modern, next generation technologies.

A conference abstract from NIRItalia online 2021 in English and Italian., The research part on oil olives work has been supported by the AGER 2 Project, grant n° 2016-0105. The authors thank Prof. Di Mattia and Dr. Federica Flamminii for their technical support.

La crescita delle instabilità del plasma può causare un'improvvisa perdita di energia termica e magnetica. In questi eventi disruttivi, gli elettroni possono venire accelerati a energie relativistiche e ottenere una frazione significativa dell'energia immagazzinata nel campo magnetico del tokamak. A queste velocità, le collisioni Coulombiane con il plasma di background diventano trascurabili e l'accelerazione dei runaway electrons è limitata solamente da effetti relativistici e perdite radiative. Quando il confinamento viene perso, il fascio energetico di runaway electrons può collidere con le componenti all'interno della camera da vuoto causando gravi danni. Gli eventi non mitigati di runaway electrons possono forzare lunghi periodi di arresto della durata di diversi mesi per consentire le riparazioni. Evitare questi scenari estremi è fondamentale per il successo di tokamak come ITER. Durante le disruzioni, i runaway electrons possono essere accelerati fino a energie nell'ordine di diversi MeV. Uno dei meccanismi che limitano questa accelerazione è l'emissione di radiazione di bremsstrahlung, causata dall'interazione delle particelle relativistiche con il plasma di background. A causa dell’elevata energia di questi elettroni, lo spettro della radiazione bremsstrahlung si estende fino a diversi MeV, nell’ intervallo di energia dei raggi X duri. Questo lavoro illustra come si possa ricostruire lo spazio di velocità dei runaway electrons dall'emissione di bremsstrahlung misurata. Nella prima metà di questo lavoro vengono discussi lo sviluppo, la caratterizzazione e l'implementazione di nuovi spettrometri a raggi X duri ottimizzati per la misura di bremsstrahlung da runaway electrons. Un nuovo spettrometro HXR compatto, con capacità di conteggio superiori a 1 Mcps, è stato sviluppato per il sistema Gamma-Ray Imager del tokamak DIII-D. Questo rivelatore si basa su un cristallo scintillatore YAP: Ce accoppiato con un fotomoltiplicatore di silicio. L'energia del rivelatore ha un ampio intervallo dinamico superiore a 20 MeV e una risoluzione energetica di circa il 9% a 661,7 keV. Il design di questo dispositivo è stato guidato dai risultati sperimentali raccolti a DIII-D con un precedente prototipo, basato su un cristallo scintillatore LYSO: Ce accoppiato con un fotomoltiplicatore di silicio. In questa sezione della tesi viene inoltre presentato lo sviluppo del Runaway Electron GAmma-Ray Detection System (REGARDS). REGARDS è un nuovo spettrometro HXR portatile a progettato per la misurazione della bremsstrahlung dei runaway electrons. Il rivelatore è basato su un cristallo scintillatore LaBr3: Ce accoppiato a un tubo fotomoltiplicatore. Il sistema ha un ampio intervallo dinamica per la spettroscopia HXR con un limite in energia superiore superiore a 20 MeV e una risoluzione energetica di circa il 3% a 661,7 keV. Il guadagno del rivelatore HXR di REGARDS è monitorato da un sistema di controllo esterno. REGARDS è stato utilizzato presso i tokamaks AUG e COMPASS. Nella seconda metà di questa tesi viene discussa l'analisi degli esperimenti di runaway electrons eseguiti presso i tokamaks AUG e JET. Un modello completo dell'emissione di bremsstrahlung è stato creato utilizzando il codice GENESIS e la funzione di risposta degli spettrometri HXR è stata generata utilizzando MCNP. La regolarizzazione di Tikhonov viene utilizzata per ricostruire la funzione di distribuzione dell'energia dei runaway electrons dalle misurazioni. Le funzioni di distribuzione di energia dei runaway electrons ricostruite consentono una descrizione quantitativa del fascio durante la scarica. Le informazioni raccolte con queste tecniche sono cruciali per comprendere la formazione di runaway electrons, per validare i modelli da principi primi e per valutare l'efficacia di diverse tecniche di mitigazione degli runaway electrons come la massive gas injection, la shattered pellet injection e la resonant magnetic perturbation. The growth of plasma instabilities can cause a sudden loss of thermal and magnetic energy. In this disruptive event, electrons can be accelerated to relativistic energies and gain a significant fraction of the energy stored in the tokamak magnetic field. At these velocities, Coulomb collisions with background plasma become negligible and the acceleration of the runaway electrons is only limited by relativistic effects and radiative losses. When the post-disruption magnetic field is lost, the energetic runaway electron beam can collide with the in-vessel plasma-facing components causing severe and localized damage. Unmitigated runaway electron events can hinder operation by forcing long shutdown periods of several months to allow repairs. The avoidance of these extreme scenarios is paramount to the success of large-scale tokamaks. The threat posed by runaway electrons is a primary focus of the fusion community. Extensive modelling and experimental campaigns are currently ongoing in most large and medium-scale tokamaks. During disruptions, runaway electrons can be accelerated up to energies in the order of several MeVs. One of the mechanisms that limit this acceleration is the emission of bremsstrahlung radiation caused by the interaction of the relativistic particles with the background plasma. Due to the extreme energy these electrons can reach, the bremsstrahlung radiation spectrum extends to several MeVs, in hard X-ray energy range. This work illustrates how information on the runaway electron velocity space can be extracted from the measured bremsstrahlung X-ray emission. In the first half of this work, the development, characterization and implementation of novel hard x-ray spectrometers optimized for runaway electron bremsstrahlung measurement are discussed. A new compact HXR spectrometer with high counting rate capabilities in excess of 1 MCps was developed for the array configuration of the tokamak DIII-D Gamma-Ray Imager system. This detector is based on a YAP:Ce scintillator crystal coupled with a silicon photomultiplier. The detector energy has a wide dynamic range in excess of 20 MeV and an energy resolution of approximately 9% at 661.7 keV. The design of this device was informed by the experimental results collected at DIII-D with a previous prototype based on a LYSO:Ce scintillator crystal coupled with a silicon photomultiplier. In this section, the development of the Runaway Electron GAmma-Ray Detection System (REGARDS) is also presented. REGARDS is a novel portable hard X-ray spectrometer designed for RE bremsstrahlung measurement. The detector is based on a LaBr3:Ce scintillator crystal coupled with a photomultiplier tube. The system has a wide dynamic range for HXR spectroscopy with an upper energy bound in excess of 20 MeV and an energy resolution of approximately 3% at 661.7 keV. REGARDS HXR detector gain is monitored by an external gain control system. REGARDS was deployed at the tokamaks AUG and COMPASS. In the second half of this thesis, analysis of the runaway electron experiments performed at the tokamaks AUG and JET is discussed. A full model of the bremsstrahlung emission is created using the GENESIS code and the HXR spectrometers response function is generated using MCNP. Tikhonov regularization is used to reconstruct the runaway energy distribution function from the measurements. The reconstructed runaway electron energy distribution functions allow for a quantitative description of the runaway electron beam throughout the discharge. The information collected with these techniques is crucial to understand runaway electron formation, to validate first-principle models and to evaluate the effectiveness of different runaway electron mitigation techniques such as massive gas injection (MGI), shattered pellet injection (SPI) and magnetic resonant perturbation (RMP).

La possibilità di controllare la materia alle dimensioni tipiche di qualche atomo ha permesso negli ultimi decenni enormi progressi in campo tecnologico. Questa miniaturizzazione è stata resa possibile dallo sviluppo di adeguate tecniche sperimentali di sintesi e controllo dei materiali, ma anche dall’introduzione di modelli teorici per descrivere i fenomeni fisici tramite il formalismo della meccanica quantistica. Questi modelli hanno permesso di descrivere la materia tramite approcci numerici, in modo da supportare, espandere ed anticipare i risultati sperimentali. Questo lavoro di tesi è concentrato sull’investigazione di interfacce create dall’accoppiamento di superfici metalliche con materiali a diversa dimensionalità. Si sono identificati i modelli più appropriati per descrivere tali sistemi ed estratte diverse quantità fisiche indicative della natura dei processi attivi alle interfacce e che potessero essere confrontate con risultati di natura sperimentale. Si sono considerati quattro casi, prototipi di materiali a diversa dimensionalità: una singola molecola organica, il pentacene, rappresentativo di un sistema isolato; catene di atomi di carbonio, rappresentativi di sistemi monodimensionali; un foglio di silicene, rappresentativo di sistemi puramente bidimensionali ed infine la ricostruzione di atomi di silicio su un substrato come caso limite per un sistema esteso. Parte dello studio è stato dedicato ad identificare le proprietà di questi sistemi in assenza di altre interazioni, ma soprattutto si è indirizzato a mostrare le modifiche a tali proprietà in presenza di diversi substrati metallici, rispettivamente Pt(111), Au(111), Ag(111) e Ag(110), caso tipico nel caso delle maggiori applicazioni nel campo dell’optoelettronica. Dal punto di vista teorico, la struttura geometrica e le proprietà elettroniche di ogni sistema sono state costruite a partire dalla teoria del funzionale densità. Tale metodo però non è sufficiente, visto che così viene costruito lo stato fondamentale del sistema: è necessario estendere i modelli per poter costruire gli stati eccitati, che tipicamente sono quelli investigati dalle tecniche sperimentali. Ogni tecnica, d’altra parte, richiede un diverso approccio per costruire e risolvere il relativo modello. In dettaglio, si è studiato lo spettro di assorbimento dei raggi x per classificare l’ interazione all’interfaccia pentacene/Pt(111) come chemisorbimento o per verificare l’impronta dell’assorbimento di catene di carbonio nel caso di molecole organiche caratterizzate da ibridazione mista di tipo sp1 e sp2. Si è investigato lo spettro di assorbimento ottico e la relativa riflettività nel caso del silicene cresciuto su Ag(111), in relazione alla struttura elettronica del sistema e delle sue modifiche indotte dalla funzionalizzazione della superficie tramite adsorbimento di singoli atomi di H o F a diversi ricoprimenti. Si è mostrato come la caratteristiche tipiche del silicene vengano perse non solo a causa del substrato, ma a causa della reattività del silicio. Come ultimo caso si sono considerati atomi di Si depositati su un film sottile di NaCl cresciuto su una superficie di Ag(110), con lo scopo di recuperare la struttura elettronica dovuta al cono di Dirac. Gli indizi contrastanti forniti da una caratterizzazione sperimentale del sistema riguardo la geometria e le proprietà elettroniche hanno richiesto un metodo diversificato per ricercare il modello più appropriato di ricostruzione degli atomi di Si. In particolare si è proceduto sia staticamente, ricercando le strutture più in accordo con la topografia emersa dagli esperimenti, ma anche tramite un approccio dinamico, volto a caratterizzare il processo stesso di aggregazione degli adatomi. Infine, si è considerata anche una ricerca ottimizzata di configurazioni casuali, basata su algoritmi genetici, ovvero ispirati al processo di selezione naturale osservato in biologia. In the last decades, the ability to control the behavior of the matter at the nanoscale has yielded many technological breakthroughs. Such miniaturization steps have been triggered not only by the development of novel experimental techniques of synthesis and characterization of the materials, but also by the introduction of advanced theoretical models based on quantum mechanics. Through these models, it has been possible to simulate the behavior of the matter in order to support, expand and also predict experimental results. The work included in this thesis is focused on investigating the interfaces created by coupling metallic surfaces with materials with different dimensionality. The models more appropriate for describing such systems have been identified in order to extract the physical properties more relevant to describe the active processes at the interfaces but also to be compared with and fully exploit the experimental data. Four cases have been taken into account, as prototypes of materials with different dimensionality: a single organic molecule, pentacene, representing the isolated system, chains of carbon atoms, representing mono-dimensional systems, a silicene sheet, representing a two-dimensional system and the reconstruction of Si atoms on a substrate as a limit case of higher dimensionality. Part of the study has been dedicated to identify the properties of the pristine materials, but the main effort has been focused on the changes of such properties induced by the presence of metallic surfaces as Pt(111), Au(111), Ag(111) and Ag(110) respectively, commonly found in opto-electronic devices. From the atomistic point of view, the geometry and the electronic properties of each system have been derived within the framework of density function theory. Such an approach is suited for the ground state only: therefore it has been necessary to extend the theoretical models to describe the excited states too, which are those commonly probed by experimental techniques. Every technique, however requires a dedicated approach to deal with and solve the related model. In particular, in this thesis the x-rays absorption spectrum has been investigated to gather insights on the interactions between pentacene and Pt(111) and to verify the contribution of carbon chains in the absorption from organic molecules with mixed sp1, sp2 hybridization states. The optical absorption has been then investigated along with the reflectivity for silicene grown on Ag(111), in relation with the electronic structure of the system and its modifications induced by the functionalization of the surface through the adsorption of H or F at different coverages. It has been shown that silicene peculiar properties are lost not only because of the presence of a substrate, but because of the reactivity itself of Si atoms. As a last case, the deposition of Si on the substrate made of a thin film of NaCl grown on Ag(110) has been investigated in order to understand whether is possible to recover the Dirac cone structure. As experimental results do not provide a solid evidence about the actual formation of a silicene overlayer, additional insight was indeed required about the structure of the reconstruction of Si atoms. Both a static and a dynamic approach have been followed, in order to find the best structure matching the experimental topography and to tailor the self-assembly process itself. Finally, the most probable configuration has been searched through a novel approach based on genetic algorithms, which are inspired by the natural selection process observed in biology to optimize the evaluation of random configurations.

Ultracold molecules have experienced increasing attention in recent years. Compared to ultracold atoms, they possess several unique properties that make them perfect candidates for the implementation of new quantum-technological applications in several fields, from quantum simulation to quantum sensing and metrology. In particular, ultracold molecules of two-electron atoms (such as strontium or ytterbium) also inherit the peculiar properties of these atomic species, above all the possibility to access metastable electronic states via direct excitation on optical clock transitions with ultimate sensitivity and accuracy. In this paper we report on the production and coherent manipulation of molecular bound states of two fermionic $^{173}$Yb atoms in different electronic (orbital) states $^1$S$_0$ and $^3$P$_0$ in proximity of a scattering resonance involving atoms in different spin and electronic states, called orbital Feshbach resonance. We demonstrate that orbital molecules can be coherently photoassociated starting from a gas of ground-state atoms in a three-dimensional optical lattices by observing several photoassociation and photodissociation cycles. We also show the possibility to coherently control the molecular internal state by using Raman-assisted transfer to swap the nuclear spin of one of the atoms forming the molecule, thus demonstrating a powerful manipulation and detection tool of these molecular bound states. Finally, by exploiting this peculiar detection technique we provide first information on the lifetime of the molecular states in a many-body setting, paving the way towards future investigations of strongly interacting Fermi gases in a still unexplored regime., Comment: 11 pages, 8 figures

M dwarfs have proven to be fascinating targets for exoplanetary search, from the growing evidence from transit (e.g., Kepler) and radial-velocity (e.g, HARPS, HARPS-N) surveys, even if several complex obstacles hamper the analysis and detection of planetary systems around them. For these reasons, it is pivotal to intensify the efforts towards the detection and characterization of extrasolar planets around M dwarfs, since new discoveries will help bring the statistical support still needed for the study of peculiar classes of planets, while the precise orbital characterization of both known and new systems will tighten the constraints on formation and migration processes. The many open issues on M dwarfs host and their planetary systems, and the development of new methodologies to investigate them, are the foundation of the motivation for my PhD work. In my thesis I first present the topic of M dwarfs exoplanetary systems, both from the observational and statistical point of view. I then report my work on performance analysis of three periodogram tools, the Generalised Lomb-Scargle Periodogram (GLS), its modified version based on Bayesian statistics (BGLS), and the multi-frequency periodogram scheme called FREquency DEComposer (FREDEC), motivated by the ubiquitousness of multiple systems with low-mass components. The results illustrated reinforce the need for the strengthening and further developing of the most aggressive and effective ab initio strategies for the robust identification of low-amplitude planetary signals in RV data sets. I describe the high-performance algorithms for single and multiple Keplerian signals modeling used by the research group I am part of, and their applications both on blindly analyzed simulated RV measurements including realistic stellar and planetary signals, and on high- precision HARPS archive data of an M dwarf star with a multiplanet system of Super Earths. I then report the first results I obtained from the analysis of RV data collected as part of the HADES (HArps-n red Dwarf Exoplanet Survey) project, that is the detection of a long-period low-mass planet orbiting the M1 dwarf GJ15A, one of the nearest stars to the Sun, which was already known to host a short-period Super Earth. Since the host star is part of a binary system with the M dwarf GJ15B, I derived an improved orbital solution for GJ15B and studied a suite of numerical simulations of the long-term evolution of the planetary system under eccentric Lidov-Kozai oscillations, which proved that this dynamical interaction can easily enhance the eccentricity of the outer planet, up to and even above the observed value. Finally, I describe the strategy and preliminary results of the ongoing Bayesian analysis of the full HADES survey, aiming to compute the occurrence rates of planets around small mass stars and the global detectability of the survey.

Galaxies assemble theirs stellar mass mostly in long timescales at a moderate rate although stochastic episodes can trigger a starburst pushing the star formation rate to extreme values for short time. The evolution of galaxies then ends with the quenching of star-formation well below the average values, possibly because of the activity of the central black hole, capable of injecting large amount of energy into the galaxy interstellar medium via outflows. Understanding the details of galaxy growth, the modes in which stars are formed within galaxies and how galaxies are quenched are still hotly debated topics and studying the properties of star-forming galaxies and the connection with the activity of the central black hole can shed light on the different mechanisms shaping galaxies across cosmic time. Star-formation episodes, black hole and outflow activity in galaxies are mainly constrained through observations in the UV-optical regime but this wavelength range is heavily affected by dust obscu- ration. As such, modeling the effect of dust on the galaxy spectrum is essential. This Thesis uses near-IR spectroscopic observations to study dusty star-forming galaxies at 0.7 ≤ z ≤ 2.5 to analyze their dust attenuation properties and investigate their ionized gas features. The sample analyzed in this work includes galaxies representative of the average star-forming population at high redshift, starburst galaxies forming stars at an exceptional rate as well as galaxies hosting an active galactic nucleus (AGN). For a sample of 79 Herschel-selected “normal” galaxies at 0.7 z 1.5 I use HST slitless spec- troscopy in the near-IR to study the attenuation on the Hα emission line. I study the Hα dust attenua- tion as a function of integrated parameters (i.e. M⋆ , S FRFIR and continuum dust attenuation) derived via spectral energy distribution fitting of the high-quality, ancillary photometric coverage from UV to far-IR. I show that the Hα emission line and the continuum are attenuated by a similar amount, unlike in the local Universe. Furthermore, I show that the Hα attenuation grows with stellar mass and this trend deviates from the local relation towards higher values of dust attenuation. Both results hint an evolution of dust attenuation properties with redshift and galaxy parameters. I also analyze the near-IR spectra of twelve starburst galaxies at z ∼ 1.6 using fiber spectroscopy from FMOS at Subaru. I measure the metal content showing that z ∼ 1.6 starbursts are metal rich, suggesting a rapid enrichment and/or a negligible role of major pristine gas inflow from the cosmic web in enhancing the star-formation. I also show tentative indications of larger density than “normal” star-forming galaxies as well as a larger ionization parameter. Most importantly, I demonstrate that the effects of dust are dramatic in this class of objects. From a comparison between dust attenuation indicators, I show in fact that ∼ 90% of star-formation is buried in heavily obscured cores so that rest-frame optical wavelengths do not provide a complete overview of starburst sources. I discuss the implications of these findings for the interpretation of distant dusty starbursts. I provide a toy model to describe the dust attenuation and distribution in these objects, warning that the metal content and interstellar medium (ISM) conditions of the most star-forming regions remain unconstrained. To better understand the connection between black hole accretion and star-forming activity, I present a preliminary study of the AGN-dominated sources among starburst galaxies at z ∼ 1.6. I use FMOS near-IR spectra to constrain their dust attenuation, finding indications that it is lower than in the star-forming parent sample. I discuss the detection of a blue-shifted component in the [OIII]5007 emission observed in the near-IR spectrum of these AGN-starbursts at z ∼ 1.6 indicating the presence of outflowing material. Furthermore, a visual inspection of the morphology reveals that AGN reside in interacting pairs more compact than star-formation dominated starbusts. If confirmed, all these preliminary results would provide strong support to the idea that AGN are cleaning their environment from dust after a buried star-formation dominated phase, a picture theorized since 30 years but not yet firmly proved. Finally, I introduce Integral Field Spectroscopic techniques in the context of the SUPER survey, an ongoing large program with SINFONI designed to unveil the role of the AGN in the life-cycle of z ∼ 2 star-forming host galaxies. IFS observations are key to add the geometrical information to the study of outflows as well as star-formation processes I present the scientific analysis on a test case from preliminary SUPER observations, to discuss the potential of SUPER observations in obtaining a complete overview of the AGN-driven outflow physics, its link with the AGN and galaxy properties and its impact on the life of the latter. Overall, this Thesis demonstrates that spectroscopic techniques are a powerful tool for constraining the properties of high-z dusty star-forming galaxies. This work also stresses the importance of a parallel, careful study of the multi-wavelength SED of galaxies spanning the electromagnetic spec- trum from the UV to the far-IR. The results presented through this work have been possible thanks to the use of multi-wavelength techniques, the ultimate approach to tackle open problems in Galaxy Evolution studies.

L’attività di ricerca presentata in questa tesi di dottorato è stata incentrata sullo sviluppo di nuovi metodi di misura per la diagnostica di sistemi polidispersi. Questa scelta nasce dalla necessità, comune a moltissime applicazioni, di osservare caratteristiche fisiche, chimiche e morfologiche della fase dispersa. La necessità di nuovi metodi di misura è rafforzata dalla parziale inadeguatezza delle tecniche disponibili per il monitoraggio di processi che coinvolgono dispersioni. L’esempio del turbidimetro è significativo. Esso è un dispositivo ottico che viene largamente impiegato nei processi di depurazione delle acque, in quanto fornisce informazioni riguardanti lo scattering complessivo dovuto alla fase dispersa. La disponibilità di nuovi metodi di misura e dispositivi capaci di rispondere a questa esigenza sarebbero d’interesse per la maggior parte dei processi di rilevanza economico sociale che coinvolgono le dispersioni quali quelli coinvolti nelle bioscienze, nella scienza dei materiali, nel monitoraggio ambientale, nell’industria alimentare e nell’industria farmaceutica. Tra le diverse soluzioni che possono essere adottate, la spettroscopia ultrasonora si è dimostrata negli anni una promettente tecnica di analisi per sistemi polidispersi, grazie alla sua applicabilità a dispersioni opache al passaggio della luce o caratterizzate da elevate concentrazioni per le quali non è possibile utilizzare tecniche basate sullo scattering della luce. Inoltre la non-invasività che la contraddistingue ne consente l'impiego in applicazioni che richiedono il monitoraggio in linea di processi produttivi. Tuttavia, i trasduttori piezoelettrici, comunemente utilizzati per la generazione e la rilevazione delle onde ultrasonore, sono caratterizzati da comportamenti risonanti che limitano la banda utilizzabile. Sebbene la ricerca nell'ambito dei materiali ferroelettrici abbia portato allo sviluppo di nuovi trasduttori con larghezze di banda sempre maggiori, il problema rimane e, per farne fronte, i diversi metodi di misura impiegati nella spettroscopia ultrasonora necessitano di elevati tempi di misura. Questa necessità limita l'applicabilità della spettroscopia ultrasonora per l'analisi e il monitoraggio di sistemi dinamici veloci per i quali non è possibile garantire la stazionarietà delle proprietà del campione per intervalli di tempo molto lunghi. In questa tesi viene presentato un nuovo metodo di misura che impiega un segnale Random Multisine a larga banda con lo scopo di ottimizzare l’energia associata alle componenti spettrali del segnale di eccitazione e ridurre i tempi di misura garantendo un’elevata risoluzione in frequenza. Oltre all’utilizzo di questo tipo di segnali nel campo della spettroscopia ad ultrasuoni, il metodo introduce tre ulteriori innovazioni: la modifica dell'algoritmo ricorsivo di sintesi del segnale per ottenere una finestratura intrinseca del segnale; l’aggiunta di un preambolo sinusoidale per migliorare il processo di stima del tempo di propagazione del segnale ultrasonoro riducendone l’incertezza; l’implementazione di un processo di pre-enfasi durante la fase di sintesi del segnale di test allo scopo di uniformare il rapporto segnale rumore di uscita, compensando la risposta in frequenza del trasduttore. Per validare sperimentalmente il metodo proposto e confrontarlo con i più comuni metodi di misura (Tone-Brust e Broadband Pulse) è stato sviluppato un setup sperimentale adatto allo scopo. I risultati ottenuti dimostrano la capacità del metodo proposto di allargare la banda osservabile e di mantenere un'incertezza uniforme rispetto al metodo Broadband Pulse, mentre consente di ridurre notevolmente i tempi di misura richiesti con il Tone-Burst. Come esempio di possibile applicazione del metodo, è stato svolto uno studio sulla qualità del latte che ha evidenziato come l'andamento della risposta in frequenza sia legato alla componente grassa dell'alimento. The research activity presented in this PhD thesis focuses on the development of new measuring methods for the analysis of polydisperse systems. This choice arises from the need, common to many applications, to observe the physical, chemical and morphological properties of the dispersed phase. The need for new measurement methods is enhanced by the partial inadequacy of the available techniques which are able to monitor processes that involve dispersions. A significant example is the turbidimeter. This optical device is widely used in water purification processes, as it provides information about the overall scattering due to the dispersed phase. However, observing only the transmittance of the sample at a macroscopic level does not allow us to say anything about the nature of the dispersed phase. New measuring methods and devices that are able to respond to this need would be of interest for the majority of the processes involving dispersions such as biosciences, nanotechnology, materials sciences, environmental monitoring, food industry, pharmaceutical industry and detergent industry. Among the different solutions that may be adopted, the ultrasonic spectroscopy has proven to be a promising technique of analysis for polydisperse systems. Its main advantage is the usability with dispersions that are opaque to the light or that are characterized by high concentrations where it is not possible to use techniques based on light scattering. In addition, this method is non-invasive, hence it is suitable to be used for applications requiring on-line monitoring of production processes. However, piezoelectric transducers, that are commonly used for the generation and detection of ultrasonic waves, have a resonant behaviour which limits the usable frequency bandwidth. Although research in the field of ferroelectric materials has led to the development of new transducers with increasing bandwidths, the problem remains open and, to deal with it, the measuring methods used in ultrasonic spectroscopy require long measurement times. This constraint limits the applicability of the ultrasonic spectroscopy for the analysis and monitoring of fast dynamic systems, for which it is not possible to guarantee the stationarity of the sample properties for long time intervals. In this thesis, a new measurement method is presented. It was developed with the aim of achieving short measurement time guaranteeing a high frequency resolution. Using a new type of broadband excitation signal, based on Random Multisine signals, the proposed method optimizes the energy associated to the spectral components of the excitation signal, obtaining a better output signal-to-noise ratio. Besides the use of this type of signals in the field of ultrasonic spectroscopy, the method introduces three additional innovations: the modification of the recursive algorithm used to synthetize the Random Multisine in order to obtain an intrinsic windowing of the signal; the addition of a single tone preamble to improve the estimation process of the propagation time; the implementation of a pre-emphasis procedure for the synthesis of the excitation signal, that compensates the transducer frequency response in order to improve the output signal-to-noise ratio. To experimentally validate the proposed method and compare it with the most common measuring methods (Tone-Burst and Broadband Pulse), an experimental setup suitable for the purpose has been developed. The obtained results demonstrate the capability of the proposed method to widen the measurable bandwidth with respect to the Broadband Pulse method and to obtain a uniform uncertainty in the band of interest. Moreover, it allows to considerably reduce the measurement times required by the Tone-burst method. Finally, a study on the quality of milk has been carried out as an example of a possible application of this method. The results showed a good correlation between the fat level of milk and its frequency response to ultrasounds.

The interaction of doxorubicin (DX) with model polynucleotides poly(dG-dC)·poly(dG-dC) (polyGC), poly(dA-dT)·poly(dA-dT) (polyAT), and calf thymus DNA has been studied by several spectroscopic techniques in phosphate buffer aqueous solutions. UV-vis, circular dichroism, and fluorescence spectroscopic data confirm that intercalation is the prevailing mode of interaction, and also reveal that the interaction with AT-rich regions leads to the transfer of excitation energy to DX not previously documented in the literature. Moreover, the DX affinity for AT sites has been found to be on the same order of magnitude as that reported for GC sites.

The aims of this research is the identification of the degradation by-products in ancient papers by means of chemical, spectroscopic and chromatographic analyses and the development of innovative methods of artificial ageing that should be able to simulate the natural degradation in these materials. For many centuries paper has been representing the main writing support for storing human knowledge. Paper is a material prone to degradation, and its conservation is a main concern, due to its obvious wide diffusion. A considerable effort has been dedicated to the paper preservation issue and it is widely recognized that a proper knowledge of the degradation reactions is essential in designing an efficient conservation treatment. To this purpose, a relevant amount of data has been collected about artificially aged paper, but just a few articles deal with naturally aged materials, since generally paper from ancient books has an artistic or historical value, and either non-destructive or micro-destructive spectroscopic techniques can be applied. In the first part of this work, (“Analysis of degradation by-products in ancient papers”, Chapter 4) a new comprehensive protocol is proposed for assessing the degradation of ancient books. The protocol is based on a multi-technique spectroscopic, chemical and analytical study of material obtained by washing leaves of ancient books. Indeed, the conservation treatments on ancient books involve frequently washing the paper leaves with water to remove the acidic by-products, which is considered a safe treatment. If the waters used for washing are collected rather than wasted, the cross-referencing of the analysis results of these “wasted waters” can provide a broad and deep insight into paper degradation by-products, thus furnishing much valuable information on both the conservation state of the books/documents in question and the degradation reactions occurring within their leaves. The proposed protocol is applied here, as a case-of-study, to the “wasted waters” obtained from washing leaves of a 16th-century-printed book, the De Divina Providentia. The widest range of analytical techniques was applied to the degradation by-products extracted from leaves in different conservation state, ranging from not degraded to very degraded. The here-proposed method is meant to become a pilot protocol for the study of ancient/historical paper degradation processes: it represents the starting point of a wider study on ancient and historical papers. Its potential application on a broad range of books and papers of different ages, origins and in different conservation state could allow for the creation of the first database on the natural by-products generated by aging in ancient books. Furthermore, a fruitful comparison with the data collected directly on ancient sheets can represent the basis for the development and the optimization of an innovative method for paper ageing (accelerated or artificial ageing methods, AAMs), able to closely simulate the natural degradation of cellulosic materials, depending on their chemical composition. In the second part of this research (“Artificial ageing by ozonation”, Chapter 5) a method for the artificial ageing of paper is proposed, aiming to reproduce oxidative by-products found in naturally aged paper. In literature, much research has been carried out in the area of paper artificial ageing, especially as regards the simulation of hydrolytic damage of paper leading to the depolymerisation of cellulose. However, other mechanisms that proceed during the natural ageing of paper, such as oxidation and autoxidation reactions, can become predominant in certain cases and therefore render these systems more complex and difficult to reproduce in the laboratory. In the last few years, much work has been performed in order to shed light on this class of reactions and on the reactive species, which promote and catalyze them. Much evidence has been collected on the role of reactive oxygen species (ROS) in the cellulose natural oxidation reactions, on their ability to induce paper radical reactions and to produce radical species in ancient papers. In general, nowadays serious and complete studies of paper radicals and, in particular, of their correlation with the paper oxidation by-products are not present in literature. In this sense, they have been reported here the first steps followed towards the development of a specific method of artificial ageing, which implies the use of ozone as a trigger for the accelerated degradation of paper. A great effort has been dedicated towards the achievement of an ozonation protocol of paper, which could reproduce the formation of both the natural degradation by-products and the open-shell species and allow for a deeper study of their nature and their effect on the writing support. The continuous comparison between the data collected on ancient papers and on artificially aged papers is the only sensible way to develop and optimize new methods for artificial or accelerated ageing of paper, able to simulate the natural degradation in cellulosic materials according to their chemical composition. The third part of this research (“Logwood inks”, Chapter 7) reports the results of the spectroscopic and analytical study on Logwood inks, carried out in cooperation with the Scientific Department of the Metropolitan Museum of Art, NYC. Fe and Cu/Fe - based Logwood inks have been synthesized following late 19threcipes and they have been characterized using UV-VIS, IR, Raman, EPR and ESI-MS analyses. This multi-technique approach is aimed to shed light on the coordination environment of the metallic ions in the colorant matrix, in order to better understand the structure of the complexes responsible for the ink colors. The UV-VIS and FT-IR spectra confirm the complexation of the metallic ions by the coloring Logwood organic matter, the hematein (Hm) macromolecule, while the Raman spectra show that the aromatic rings, composing the molecule, are also involved in the interaction. The high-sensitivity of the EPR technique allows for a deeper study of the ink structure giving information about the coordination environment of the metal ions. It turns out, together with ESI-MS, as the only technique, among the applied ones, that can provide a unique outline for each ink. Unexpected results are obtained by the ESI-MS analyses: for the first time in literature, mass analysis of Logwood inks has demonstrated the breakdown of Hm molecules during the ink preparation, as just complexed cathecols and/or byciclic compounds were identified as the main component of the three inks. These chemical species are very similar to the ones which compose the iron gall inks: the Fe(II)/Fe(III)-pyrogallates.

2010 - 2011, Many drugs are available for the treatment of systemic or superficial mycoses, but only a limited number of them are effective antifungal drugs, devoid of toxic and undesirable side effects. Therefore there remains an urgent need for a new generation of antifungal agents. The present work concerns the synthesis, the antifungal activity and the biophysical characterization of a set of linear and cyclic peptides (AMT1, cyclo-AMT1, AMT2, cyclo-AMT2, AMT3, cyclo-AMT3) including aminoacids characteristic of membrane-active antimicrobial peptides (AMP). The peptides were tested against different yeast species, and displayed general antifungal activity, with a therapeutically promising antifungal specificity against Cryptococcus neoformans. To shed light on the role played by the membrane cell in the antifungal activity an extensive biophysical study was carried out using different spectroscopic techniques. Our structural investigation provides data to exclude the ability of the peptides to penetrate the membrane of the fungal cell, highlighting their attitude to interact with the external surface of the bilayer. Taken together our data support the hypothesis that the membrane cell of the fungi may be an important platform for specific interactions of the synthesized peptides with more specific targets involved in the cell wall synthesis. Viral fusion glycoproteins present a membrane-proximal external region (MPER) which is usually rich in aromatic residues and presents a marked tendency to stably reside at the membrane interfaces, leading, through unknown mechanisms, to a destabilization of the bilayer structure. This step has been proposed to be fundamental for the fusion process between target membrane and viral envelope. In present work, we investigate the interaction between an octapeptide (C8) deriving from the MPER domain of gp36 of Feline Immunodeficiency Virus and different membrane models by combining experimental results obtained by Nuclear Magnetic Resonance, Electron Spin Resonance, Circular Dichroism and Fluorescence Spectroscopy with Molecular Dynamics simulations. Our data indicate that C8 binds to the lipid bilayer adsorbing onto the membrane surface without deep penetration. As a consequence of this interaction, the bilayer thickness decreases. The association of the peptide with the lipid membrane is driven by hydrogen bonds as well as hydrophobic interactions that the Trp side chains form with the lipid headgroups. Notably these interactions may be the key to interpret at molecular level the function played by Trp residues in all the fragments of viral envelope involved in fusion mechanism with target membrane. [edited by author], X n.s.

The continue demand to increase the efficiency and reliability of aeronautical and/or energy gas turbines has led to develop new Ni superalloys having a greater volume fraction of characteristic hardening g' phase respect to the g phase. Nonetheless the considerable mechanical resistance of these materials is due to the specific microstructural mutual arrangement and shape of the two phases, too. In particular the g'+ g structure is not stable during creep: when at higher temperatures the alloy is subjected to a mono-axial tensile stress at the direction , the original cuboidal g' structure changes to an anisotropic lamellar structure (rafts), perpendicular to the load direction. This effect depends on the lattice misfit between the two phases. The lattice parameters of the phases are temperature dependent, since the thermal expansion coefficient of g' is lower than that of g, and the partition of chemical elements between the two phases changes with temperature because of diffusion phenomena. In addition, the relative composition of the two phases can be influenced by the stress state during creep. This work presents the potentiality of high resolution Scanning PhotoEmission Microscopy (SPEM) on the study of the diffusion phenomena taking place between g and g' phases of a Ni superalloy after creep. In particular the results on the single-crystal superalloy CM186LC, before and after creep tests at temperature of 800°C and 900°C, are reported, indicating that SPEM can be useful to study the aforesaid microstructural evolution with creep for the material. The XPS measurements with high spatial resolution and the SPEM analysis, operating both in punctual spectroscopy modality and image configuration, have been carried out at the beam-line ESCA-microscopy at the synchrotron Elettra in Trieste (Italy). By XPS analysis it has been possible to quantify the present elements and their chemical state, whilst by SPEM technique the element distribution on the two phases ?'and ? has been determined. In particular the latter technique is able to analyze the compositions of the two different phases without surface chemical etching. In the considered case it has been observed as the formation of the rafts during creep occurs especially with the diffusion of W e Hf from ? phase to ?' phase. The variations of the relative quantities for the elements into the phases have been observed at the higher creep test temperature, that is 900 °C. W is homogeneously distributed, whilst Hf is totally in ?'.

CO recombination kinetics has been investigated in the type II truncated hemoglobin from Thermobifida fusca (Tf-trHb) over more than 10 time decades (from 1 ps to 100 ms) by combining femtosecond transient absorption, nanosecond laser flash photolysis and optoacoustic spectroscopy. Photolysis is followed by a rapid geminate recombination with a time constant of 2 ns representing almost 60% of the overall reaction. An additional, small amplitude geminate recombination was identified at 100 ns. Finally, CO pressure dependent measurements brought out the presence of two transient species in the second order rebinding phase, with time constants ranging from 3 to 100 ms. The available experimental evidence suggests that the two transients are due to the presence of two conformations which do not interconvert within the time frame of the experiment. Computational studies revealed that the plasticity of protein structure is able to define a branched pathway connecting the ligand binding site and the solvent. This allowed to build a kinetic model capable of describing the complete time course of the CO rebinding kinetics to Tf-trHb. Fil: Marcelli, Agnese. European Laboratory for Non-Linear Spectroscopy; Italia Fil: Abbruzzetti, Stefania. Università di Parma; Italia Fil: Bustamante, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Feis, Alessandro. University of Florence; Italia Fil: Bonamore, Alessandra. Università degli studi di Roma "La Sapienza"; Italia Fil: Boffi, Alberto. Università degli studi di Roma "La Sapienza"; Italia Fil: Gellini, Cristina. University of Florence; Italia Fil: Salvi, Pier R.. University of Florence; Italia Fil: Estrin, Dario Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Bruno, Stefano. Università di Parma; Italia Fil: Viappiani, Cristiano. Università di Parma; Italia Fil: Foggi, Paolo. European Laboratory for Non-Linear Spectroscopy; Italia. University of Perugia; Italia

Polarization resolved absorption spectra of a strain-compensated Ge multiple quantum well (MQW) structure with Ge-rich SiGe barriers have been calculated with an $s{p}^{3}{d}^{5}{s}^{\ensuremath{\ast}}$ tight-binding model and measured for light propagating perpendicular to the growth direction. The MQW was grown by low-energy plasma-enhanced chemical vapor deposition and consists of 50 Ge quantum wells deposited onto a thick graded ${\text{Si}}_{1\ensuremath{-}x}{\text{Ge}}_{x}$ buffer layer. The MQW was structurally characterized by high-resolution x-ray diffraction. The measured absorption spectra show clear quantum confined excitonic transitions related to the $\text{Ge}\text{ }\ensuremath{\Gamma}$ point band gap, and strong dependence on the incident light polarization, as expected from selection rules for type I direct gap quantum confined systems. A good agreement between theoretically predicted spectra and experimental data is found, demonstrating light and heavy hole polarization-dependent selection rules in Ge MQWs.

The MARSCHALS (Millimetre-wave Airborne Receiver for Spectroscopic CHaracterisation of Atmospheric Limb-Sounding) project has the general objectives of demonstrating the measurement capabilities of a limb viewing instrument working in the millimetre and sub-millimetre spectral regions (from 294 to 349 GHz) for the study of the Upper Troposphere – Lower Stratosphere (UTLS). MARSCHALS has flown on board the M-55 stratospheric aircraft (Geophysica) in two measurements campaigns. Here we report the results of the analysis of MARSCHALS measurements during the SCOUT-O3 campaign held in Darwin (Australia) in December 2005 obtained with MARC (Millimetre-wave Atmospheric-Retrieval Code). MARSCHALS measured vertical distributions of temperature, water vapour, ozone and nitric acid in the altitude range from 10 to 20 km in presence of clouds that obscure measurements in the middle infrared spectroscopic region. The minimum altitude at which the retrieval has been possible is determined by the high water concentration typical of the tropical region rather than the extensive cloud coverage experienced during the flight. Water has been measured from 10 km to flight altitude (~18 km) with a 10% accuracy, ozone from 14 km to flight altitude with accuracy ranging from 10% to 60%, while the retrieval of nitric acid has been possible with an accuracy not better than 40% only from 16 km to flight altitude due to the low signal to noise ratio of its emission in the analysed spectral region. The results have been validated using measurement made in a less cloudy region by MIPAS-STR, an infrared limb-viewing instrument on board the M-55, during the same flight.

The MARSCHALS (Millimetre-wave Airborne Receiver for Spectroscopic CHaracterisation of Atmospheric Limb-Sounding) project has the general objectives of demonstrating the measurement capabilities of a limb viewing instrument working in the millimetre and sub-millimetre spectral regions (from 294 to 349 GHz) for the study of the Upper Troposphere - Lower Stratosphere (UTLS). MARSCHALS has flown on board the M-55 stratospheric aircraft (Geophysica) in two measurements campaigns. Here we report the results of the analysis of MARSCHALS measurements during the SCOUT-O3 campaign held in Darwin (Australia) in December 2005 obtained with MARC (Millimetrewave Atmospheric-Retrieval Code). MARSCHALS measured vertical distributions of temperature, water vapour, ozone and nitric acid in the altitude range from 10 to 20 km in presence of clouds that obscure measurements in the middle infrared spectroscopic region. The minimum altitude at which the retrieval has been possible is determined by the high water concentration typical of the tropical region rather than the extensive cloud coverage experienced during the flight. Water has been measured from 10 km to flight altitude (18 km) with a 10% accuracy, ozone from 14 km to flight altitude with accuracy ranging from 10% to 60%, while the retrieval of nitric acid has been possible with an accuracy not better than 40% only from 16 km to flight altitude due to the low signal to noise ratio of its emission in the analysed spectral region. The results have been validated using measurement made in a less cloudy region by MIPAS-STR, an infrared limb-viewing instrument on board the M-55, during the same flight.

Recently four very young families were discovered: the Datura, Emilkowalski, 1992 YC2, and Lucascavin clusters are 450 ± 50, 220 ± 30, 50-250, and 300-800 kyr old, respectively. To date, these clus- ters are the only known asteroid families younger than 1 Myr. The Datura cluster is a group of seven asteroids while the three other new families are groups of three objects each. All these objects have diameters in the ~ 1-11 km range with >60% of the objects having D< 2km. These discoveries offer an excellent opportu- nity for physical studies of young families whose members have suffered limited erosion. It is known that a planetary surface exposed to space weathering effects (solar wind ion irradiation, cosmic rays and interplanetary dust bombardment) changes in color and spectral characteristics. The effect, in the inner part of the solar system, is a progressive darkening of the surfaces, and a reddening of the reflectance spectra. In the case of these families we expect the surfaces to be young (quite unweathered). Especially, the relatively precise dating of the fragmentation events will allow us to put a time tag on the effects of space weathering. We will present visible (0.45-0.95 µm) and near-infrared (0.7-2.5 µm) spectroscopic observations for 1270 Datura and 14627 Emilkowalski and a visi- ble spectrum for 21509 Lucascavin. Results: We will show that the surfaces, even if young, have already undergone some significant amount of space weathering (SW). These observations prone a fast acting SW process responsible for these reddish colors.