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Intramolecular hydrogen transfer, a reaction where donor and acceptor sites of a hydrogen atom are part of the same molecule, is a ubiquitous reaction in biochemistry and organic synthesis. In this work, we report hydronium ion (H₃O⁺) production from aminobenzoic acid (ABA) after core-level ionization with soft X-ray synchrotron radiation. The formation of H₃O⁺ during the fragmentation requires that at least two hydrogen atoms migrate to one of the oxygen atoms within the molecule. The comparison of two structural isomers, ortho- and meta-ABA, revealed that the production of H₃O⁺ depends strongly on the structure of the molecule, the ortho-isomer being much more prone to produce H₃O⁺. The isomer-dependency suggests that the amine group acts as a donor in the hydrogen transfer process. In the case of ortho-ABA, detailed H₃O⁺ production pathways were investigated using photoelectron-photoion-photoion coincidence (PEPIPICO) spectroscopy. It was found that H₃O⁺ can result from a direct two-body dissociation but also from sequential fragmentation processes.

The detailed understanding of the behavior of the electronic states of multielectron atoms and small molecules is fundamental for advancement in a wide variety of fields. The present work aims at deepening this understanding by studying elusive, small cross section processes during photoionization and decay, beyond the dominant well-known processes. The branching ratio and anisotropy parameters of the satellite states accompanying the Kr 3d photoionization line were measured, shedding light on their creation mechanisms, with the support of theoretical results. By utilizing electron coincidence techniques, a method to measure the possibility of interatomic Auger effect in N2O could be illustrated and an upper limit on the probability established. The binding energies of the nitrogen 1s−1v−1 states in N2O were also measured. For this study, a multi-electron coincidence analyzer was developed. Furthermore, the decay of argon 2p−2 double core hole states populated by Auger decay after 1s ionization was studied by measuring electron-ion coincidences. Theoretical calculations allowed the assignment of intermediate and final states. All experiments were carried out at synchrotron facilities., Tiivistelmä Monielektronisten atomien ja pienten molekyylien elektronisten tilojen yksityiskohtainen ymmärtäminen luo pohjaa monien eri alojen kehittymiselle. Tämän työn tavoitteena on edistää tätä ymmärrystä tutkimalla hallitsevien tunnettujen siirtymien sijasta vaikeasti havaittavia, pienen vaikutusalan fotoionisaatioprosesseja ja elektronisten tilojen purkautumisia. Kr 3d -fotoionisaatioviivan satelliittitilojen intensiteettisuhteet ja anisotropiaparametrit mitattiin, ja vertaamalla tuloksia koetta tukeviin teoreettisiin laskuihin saatiin tietoa satelliittitilojen syntymekanismeista. Työssä esitettiin menetelmä atomien välisen Auger-ilmiön todennäköisyyden mittaamiseksi N2O:ssa elektronikoinsidenssitekniikoita käyttäen ja määritettiin prosessin todennäköisyyden yläraja. Myös N2O:n typen 1s−1v−1-tilojen sidosenergiat mitattiin. Tätä tutkimusta varten kehitettiin koinsidenssianalysaattori, jolla voidaan mitata useita elektroneja yhtäaikaisesti. Lisäksi argonin 1s-ionisaation Auger-purkautumisen seurauksena syntyvien 2p−2 sisäkuoren kaksoisaukkotilojen purkautumista tutkittiin mittaamalla elektroni-ioni-koinsidensseja. Teoreettisten laskujen avulla purkautumisprosessin väli- ja lopputiloja pystyttiin tunnistamaan. Väitöstyön kaikki kokeet suoritettiin synkrotronisäteilylaitoksissa.

Welcome to ICESS 15th Welcome to the 15th ICESS conference! Finally, after five years of waiting it is our pleasure to welcome you - the whole international community – to Oulu, Finland. The scientific program built in collaboration with international advisory board (IAB) covers widely the areas of research and surely engages plenty of discussions and ideas for future collaborations. Great thanks for participating and making the event possible! Let us all make the event pleasant respecting the diversity and committing to strengthening the international community of ICESS. Welcome to Oulu! ICESS local committee: Marko Huttula, chair Minna Patanen, program committee Samuli Urpelainen, Satu Ojala, local organization

The interatomic Auger effect following O 1s ionization in N₂O has been experimentally investigated using multi-electron coincidence spectroscopy. The expected transition energies have been established by comparison to the measured N 1s⁻¹v⁻¹ core-valence double ionization energies. We describe a procedure to eliminate the background of two competing processes contributing spectroscopic signatures to the same energy range, namely double Auger decay of the O 1s vacancy and direct single-photon double ionization into the N 1s⁻¹v⁻¹ states. While the interatomic Auger transitions could not be successfully isolated, we provide an upper boundary of the transition probability of 0.07% with respect to the dominant single Auger decay after O 1s ionization.

Scanning transmission X-ray microscopy (STXM) in the soft X-ray range is well-suited to study ultrastructural features of mammalian soft tissues. Especially at the carbon 1s edge, the imaging contrast varies drastically across the edge due to rapid changes in the X-ray absorption cross-section of functional groups present in the tissue samples enabling label-free soft X-ray spectromicroscopic studies. We present STXM spectromicroscopic imaging of mouse kidney and liver tissues. We especially concentrate on ultrastructural abnormalities in genetically modified Slc17a5 mice. STXM is a promising technique to study storage diseases without chemical alteration due to staining agents, but sample preparation poses a challenge.

Silica-titania (70/30) supported vanadium catalysts were prepared, characterized, and studied in oxidative dehydrogenation of sulfur-contaminated methanol. The quality of vanadia species is dependent on temperature and gas conditions during preparation, support type, support specific surface area and VOx surface density. For example, upon heating the amount of V2O5 decrease along with formation of polymeric species. Such changes may occur also during the catalytic reaction. The reaction experiments and characterization results showed that the stability of polymeric vanadia species and total acidity has a connection with better formaldehyde production performance. The best performance was observed for N2-calcined silica-titania catalyst. Easy reducibility of the catalyst, as in the case of reference catalysts, leads to further oxidation of formaldehyde.

The microstructure, mechanical properties, and corrosion resistance to simulated body fluid solution behavior of as-extruded Mg-1.8Zn-0.5Zr alloys with different Gd additions are investigated. It is found that dynamic recrystallization occurs in the alloys during extrusion and the grain size gradually decreases with Gd alloying. The mechanical properties and corrosion resistance to simulated body fluid of the investigated alloys enhance firstly and then weaken with the increase in Gd content. The results reveal that the Mg-1.8Zn-0.5Zr with a 1.5 wt.% Gd addition has optimized mechanical properties and corrosion resistance. A three-stage corrosion mechanism, including sequential stages from hydroxidation, phosphatization and hydroxidation, to formation-dissolution dynamic equilibrium, is proposed through electrochemical measurements and corroded surface analyses. This study reveals the extruded Mg-1.8Zn-0.5Zr-1.5Gd alloy can be regarded as a potential candidate for using as biodegradable magnesium implants.

Neural mechanisms behind stereopsis, which requires simultaneous disparity inputs from two eyes, have remained mysterious. Here we show how ultrafast mirror-symmetric photomechanical contractions in the frontal forward-facing left and right eye photoreceptors give Drosophila superresolution three-dimensional (3D) vision. By interlinking multiscale in vivo assays with multiscale simulations, we reveal how these photoreceptor microsaccades—by verging, diverging, and narrowing the eyes’ overlapping receptive fields—channel depth information, as phasic binocular image motion disparity signals in time. We further show how peripherally, outside stereopsis, microsaccadic sampling tracks a flying fly’s optic flow field to better resolve the world in motion. These results change our understanding of how insect compound eyes work and suggest a general dynamic stereo-information sampling strategy for animals, robots, and sensors.

The crystallization in glasses is a paradoxical phenomenon and scarcely investigated. This work explores the non-isothermal crystallization of a multicomponent alumino-borosilicate glass via in situ high-energy synchrotron X-ray diffraction, atomic pair distribution function, and Raman spectroscopy. Results depict the crystallization sequence as Ca3Al2O6 and CaSiO4 followed by LiAlO2 with the final compound formation of Ca3B2O6. These precipitations occur in a narrow temperature range and overlap, resulting in a single exothermic peak in the differential scanning calorimetry thermogram. The concurrent nucleation of Ca3Al2O6 and CaSiO4 is intermediated by their corresponding hydrates, which have dominantly short-range order. Moreover, the crystallization of LiAlO2 and Ca3B2O6 is strongly linked with the changes of structural units during the incubation stage in non-isothermal heating. These findings clarify the crystallization of multicomponent glass, which have been inferred from ex situ reports but never evidenced via in situ studies.

In contemporary steelmaking, burners are widely used for heating slabs in walking beam and annealing furnaces, heat-up of empty ladles, flame cutting of steel, as well as providing additional energy in electric arc furnaces. To facilitate the future of carbon-neutral steelmaking, a transition from natural gas-based burners toward hydrogen-based burners is essential to reduce the CO2 emissions associated with the burners. In addition to this transition, it is important also to optimize the burner practices that are used today, since the transition will take its time. To this end, CO2 reductions could also be realized with process control aiming toward more efficient use of energy and gas resources. This study presents how optical emission spectroscopy could be used for on-line monitoring and process control of the burner flame. A case study of oxy-fuel cutting is presented, where optical emissions from H2O, C2, FeO, Na, and K together with thermal radiation were observed. The flame’s properties, such as temperature and radiative heat transfer, identification of the flame species and impurities, and detection of rapid changes in the flame are analyzed from the OES data.

In the world of ever-increasing demand for carbon-free steel, hydrogen and recycling have an undeniable role in achieving net-zero carbon dioxide emissions for the steel industry. However, even though steel is one of the most recycled materials globally, the quantity of steel that can be made from recycled steel will probably not match the demand in the future. This in turn means that steel must be also produced from the conventional resource, the iron ore. Hydrogen has been proposed as an environmentally friendly alternative to carbon as a reducing agent. To tackle the problems related to the usage of hydrogen for this purpose, hydrogen plasma smelting reduction has been studied extensively in the last few years. This article aims to provide means for process control of the hydrogen plasma, which may show erratic and chaotic behavior during the smelting process. The method used is optical emission spectroscopy, with which the plasma can be characterized, its composition can be evaluated, and its temporal evolution can be assessed. This study sheds light on how the plasma behaves with different electrode gaps and flow gas compositions together with how the position of the arc with respect to the center of the crucible can be assessed. In Ar/H₂ plasma, the plasma temperatures derived with OES varied between 4000 and 10000 K, and up to a 26% decrease in electron density was observed when increasing the electrode gap in 1 cm increments.

The overwhelming impact of complex-phase microstructures to mechanical response in multiphase steels requires accurate constitutive properties of the individual phases. However, precise prediction of individual phase properties to their mechanical response is critical and sophisticated, and commonly requires multiscale characterizations and numerous approximations. In this work, by employing full phase information and semi-empirical analytical models, we accurately predict the yield strength of deformed variants of Ce-modified SAF2507 super duplex stainless steel (SDSS). High energy synchrotron X-ray diffraction (HE-SXRD) reveals the phase fractions of major phases along with secondary phases of Cr₂N and eutectic CexFey. Average lattice strain/crystallite size of the austenite and ferrite/martensite phases from the measured volume is estimated through the Williamson-Hall method. A unique composite strengthening type analytical model is used to estimate yield strength by taking individual strengthening contributions from all phases, their grain sizes, stored dislocation densities, solid solution, and precipitates. Close agreement between reconstructed and experimental yield strength is observed for several cold and cryogenic rolled SDSS. A combination of HE-SXRD and analytical model offers a time-effective virtual design pathway to engineer high-strength steel.

Though carbonates are known for several decades, their role in sun-light driven photocatalysis is still hidden. Herein, carbonate boosted solar water splitting in nickel-based plasmonic hybrid nanostructures is disclosed for the first time via in-situ experiments and density-functional theory (DFT)-based calculations. Ni@NiO/NiCO₃ core@shell (shell consisting of crystalline NiO and amorphous NiCO₃) nanostructure with varying size and compositions are studied for hydrogen production. The visible light absorption at ∼470 nm excludes the possibility of NiO as an active photocatalyst, emphasizing plasmon driven H₂ evolution. Under white light irradiation, higher hydrogen yield of ∼80 µmol/g/h for vacuum annealed sample over pristine (∼50 µmol/g/h) complements the spectroscopic data and DFT results, uncovering amorphous NiCO₃ as an active site for H₂ absorption due to its unique electronic structure. This conclusion also supports the time-resolved photoluminescence results, indicating that the plasmonic electrons originating from Ni are transferred to NiCO₃ via NiO. The H₂ evolution rate can further be enhanced and tuned by the incorporation of NiO between Ni and NiCO₃.

The steel industry is on its way towards more environmentally friendly steelmaking. To achieve the ambitious goals of significant CO₂ emissions reduction, new processes, practices, sources of on-line data, and digitalization together with automation will be required. To address these issues, this paper discusses optical emission spectroscopy (OES) as an on-line data acquisition method for industrial electric arc furnaces and ladle furnaces. The current state of the OES as a measurement method in the steel industry together with prospects of new applications are presented with examples based on the authors’ prior research.

The upgradation of the ilmenite ore, using a pyrometallurgy method, is performed using a carbothermic reduction of the ilmenite. A high titania slag is obtained which is used as a feedstock for the TiO₂ pigment production. The slag is cooled after tapping in big molds and can take ten days to cool. This cooling method has remained the same since the inception of ilmenite smelting and recently rapid cooling through granulation has been utilized. The work presented in this paper focuses on the microstructural study of the slags that were prepared using different techniques and cooled at different cooling rates. Various analytical techniques, such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma-optical emission spectroscopy (ICP-OES), and X-ray photoelectron spectroscopy (XPS) were used to exhibit the similarity of these synthetic slags to the properties of high titania ilmenite slag. The slag consisted mostly of pseudo-brookite phase with a M₃O₅ stoichiometry and smaller amounts of silicate and rutile phase. A glassy phase of silica was observed and most of the impurities were found to be present in the silicate phase. These silica phases were observed to be separate from the pseudo-brookite phase and along the phase boundaries. Micro-cracking of the slag surface, which is the characteristic of the M₃O₅ phase formed in the ilmenite slag, were observed under the SEM analysis. The XPS analysis revealed that faster cooling does result in lower amount of oxidation but the difference in the TiO₂ and Ti₂O₃ composition can have larger impact on oxidation than the cooling speed.

Core ionization dynamics of argon–water heteroclusters ArM[H₂O]N are investigated using a site and process selective experimental scheme combining 3 keV electron irradiation with Auger electron–ion–ion multi-coincidence detection. The formation of Ar 2p⁻¹ vacancies followed by non-radiative decay to intermediate one-site doubly ionized states Ar²⁺(3p⁻²)−ArM−1[H₂O]N and subsequent redistribution of charge to the cluster environment are monitored. At low argon concentrations the emission of an [H₂O]n′H⁺/[H₂O]n′′H⁺ ion pair is the dominant outcome, implying on high efficiency of charge transfer to the water network. Increasing the condensation fraction of argon in the mixed clusters and/or to pure argon clusters is reflected as a growing yield of Arm′+/Arm′′+ ion pairs, providing a fingerprint of the precursor heterocluster beam composition. The coincident Auger electron spectra, resolved with better than 1 eV resolution, show only subtle differences and thereby reflect the local nature of the initial Auger decay step. The results lead to better understanding of inner shell ionization processes in heterogeneous clusters and in aqueous environments in general.

The formation of multicomponent aerosol particles from precursor solution droplets often involves segregation and surface enrichment of the different solutes, resulting in non-homogeneous particle structures and diverse morphologies. In particular, these effects can have a significant influence on the chemical composition of the particle–vapor interface. In this work, we investigate the bulk/surface partitioning of inorganic ions, Na⁺, Mg² ⁺, Ca² ⁺, Cl⁻ and Br⁻, in atomiser-generated submicron aerosols using synchrotron radiation based X-ray photoelectron spectroscopy (XPS). Specifically, the chemical compositions of the outermost few nm thick surface layers of non-supported MgCl₂/CaCl₂ and NaBr/MgBr₂ particles are determined. It is found that in MgCl₂/CaCl₂ particles, the relative abundance of the two species in the particle surface correlates well with their mixing ratio in the parent aqueous solution. In stark contrast, extreme surface enrichment of Mg² ⁺ is observed in NaBr/MgBr₂ particles formed from both aqueous and organic solution droplets, indicative of core–shell structures. Structural properties and hydration state of the particles are discussed.

In this thesis, properties of freestanding atomic/molecular clusters are experimentally addressed using various synchrotron radiation and electron ionization based electron and ion spectroscopic methods. The work focuses on water clusters with and without dopant atoms/molecules, including ≲3nm sized [H₂O]N, [H₂O]N[KCl]M, [H₂O]NArM and ArN clusters. The surface properties of larger 100–200nm sized MgCl₂/CaCl₂ and MgBr₂/NaBr nanoparticles generated from precursor solution droplets are also investigated. The experiments provide fundamental level information on the particles’ chemical and structural composition in relation to their formation conditions, electronic properties, and dynamical response to ionizing radiation. Instrumentation was also developed for the generation and characterization of the clusters.

Electric arc furnaces and ladle furnaces have an important role in the future of steelmaking where CO₂ emissions have to be mitigated to an acceptable level. One way to address this goal is to optimize and improve the current practices by adjusting the chemistry and reactions with material additions or gas injections. These procedures would greatly benefit from on-line slag composition analysis. Since the electric arcs radiate throughout the melting, optical emission spectroscopy is a potential method for such analysis. In this study, optical emissions from the electric arc are measured in a laboratory environment. Dozens of atomic emission lines were correlated with Cr₂O₃, Fe₂O₃, Al₂O₃, SiO₂, MnO, MgO, CaO, CaF₂, V₂O₅, and Ni content of the slag together with correlation between CaF₂ and molecular optical emission bands of CaF. Optimal spectral resolution for industrial applications was deducted to be between 0.022 and 0.179 nm.