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This study describes a simple method to generate sub-20 fs UV-pulses (264 nm) by third-harmonic generation, in an air-plasma filament formed after focusing the fundamental 800 nm beam directly in the lab open-atmosphere. The generated pulses are applied to track the relaxation through the conical intersection that couples the S2 and S1 states, in the benchmark molecule of naphthalene. The transients, with a resolution of about 25 fs, show two differentiate patterns of quantum beats. The assignation of these oscillations to specific modes in the lower S1 state and to electronic coherence between the two coupled states is discussed. All the experiments were carried out at the CLPU facility. The authors acknowledge the assistance from the CLPU technical and administrative personnel. They also thank the financial support from the Spanish MINECO through the grant: PGC2018-098561-B-C21. The work was also funded by the Basque Government (IT1162-19 and IT1491-22). I. Lamas thanks the UPV/EHU for his predoctoral fellowship. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, ESF) is also gratefully acknowledged. The authors greatly appreciate the Open Access funding provided by University of Basque Country.

This thesis deals with the dynamical processes in atoms and small molecules initiated by the absorption of ultrashort, coherent light pulses. The studied phenomena takeplace on the femtosecond (1 fs = 10−15 s) and attosecond (1 as = 10−18 s) timescales and critically depend on the properties of the light fields that drive them. Wework with infrared (IR) femtosecond laser pulses, which we manipulate through nonlinear interactions with matter to either study these interactions themselves or applythem to investigate other light-induced processes.One part of this thesis focuses on the generation and characterisation of IR pulses spectrally broadened through the Kerr effect. We use a technique called dispersion scanto temporally compress and at the same time measure pulses broadened in gas-filled hollow-core fibres. We propose multiple improvements to this well-established characterisation technique. Further, we investigate femtosecond filamentation in gases, a process with highly complex dynamics involving several non-linear processes including the Kerr effect and ionisation. We develop a method that allows us to measure the electric field of a laser pulse undergoing filamentation in three dimensions, whilealso scanning along the filament length. Our technique provides access to pulses with desirable characteristics that may be generated at a point inside the filament, simultaneously enabling their measurement and extraction for applications. In addition, this technique opens up the possibility to explore intricate filament dynamics.In the other part of this work, we up-convert the IR laser pulses into trains of extreme ultraviolet (XUV) attosecond pulses through a non-linear process called high-orderharmonic generation. We combine the IR and XUV pulses to study the photoionisation dynamics in different species using a method known as RABBIT (Reconstructionof Attosecond Beating By Interference of Two-photon transitions). In this technique, a target gas is ionised by the XUV field, creating an electron wave-paket (EWP) in thecontinuum, while a weak IR pulse probes the system. The EWP scatters off the ionic potential, acquiring an additional phase as it propagates. Recording the photoelectronspectrum as a function of the IR-XUV time delay allows us to infer time-resolved information about the ionic potential. We apply this method to investigate the dynamicsof different ionisation processes in noble gases (He, Ar, and Xe) and the N2 molecule. The high spectral resolution of our electron spectrometer allows us to disentanglethe contributions from different ionisation channels. In addition, we perform angle-resolved measurements, investigating the coherent superposition of final stateswith different angular momenta.

A multitude of ultrafast photoinduced reactions in organic semiconductors are governed by the close interplay between nuclear and electronic degrees of freedom. From biological light-harvesting and photoprotection to organic solar cells, the critical electronic dynamics are often precisely synchronized with and driven by nuclear motions, in a breakdown of the Born-Oppenheimer approximation. Ultrafast time-domain Raman methods exploit impulsive excitation to generate nuclear wavepackets and track their coherent evolution through these reaction pathways in real time. This tool of vibrational coherence has recently been applied to study singlet fission, a carrier multiplication process with the potential to boost solar cell efficiencies which has been under intense mechanistic investigation for the past decade. In this review, we present the essential features of the spectroscopic techniques and discuss how they have been used to elaborate a new perspective on the singlet fission mechanism. It is now established that ultrafast triplet-pair formation is driven by vibronic coupling, whether fission is exothermic or endothermic, and thus that full understanding of singlet fission requires explicit consideration of nuclear dynamics. Despite broad qualitative agreement between different vibrational coherence methods, differences in the detailed observations and interpretation raise important questions and pose new challenges for future research.

This work provides the evidence to apply simulation methods that are applicable to systems with structural randomness to simulate crystalline materials at high temperatures. My work not only open the avenue to expand the simulation capability of materials but also provides insight to the physics of vibrations of atoms under different temperature and for different types of materials. I have also evaluated the reliability of Molecular Dynamics simulations at the frequency level and found that theses types of simulations, despite the previous belief, are reliable at low temperatures but up to a measurable frequency. In addition, the result of my work explains the reason for high thermal conductivity of amorphous silicon by showing computational evidence for the presence of high wavelength modes in this material and this work is the first computational work reaching reported low-frequency modes.

We illustrate the state of the art in time-dependent calculations on systems of chemical interest. In particular, our exposition covers the Gaussian multiconfiguration time-dependent Hartree/variational multiconfiguration Gaussian approach in nuclear dynamics, where the scope is that of explaining dynamical effects in various physicochemical processes. Conversely, the Rice–Ramsperger–Kassel–Marcus/master equation kinetic methods are also examined, used to calculate rate constants of gas phase processes (used in the modeling of combustion, atmospheric, and astrochemical processes).

We present the non-adiabatic, conical-intersection quantum dynamics of the title collision where reactants and products are in the ground electronic states. Initial-state-resolved reaction probabilities, total integral cross sections, and rate constants of two H 2 vibrational states, v 0 = 0 and 1, in the ground rotational state (j 0 = 0) are obtained at collision energies E coll ≤ 3 eV. We employ the lowest two excited diabatic electronic states of HeH2+ and their electronic coupling, a coupled-channel time-dependent real wavepacket method, and a flux analysis. Both probabilities and cross sections present a few groups of resonances at low E coll , whose amplitudes decrease with the energy, due to an ion-induced dipole interaction in the entrance channel. At higher E coll , reaction probabilities and cross sections increase monotonically up to 3 eV, remaining however quite small. When H 2 is in the v 0 = 1 state, the reactivity increases by ~2 orders of magnitude at the lowest energies and by ~1 order at the highest ones. Initial-state resolved rate constants at room temperature are equal to 1.74 × 10 -14 and to 1.98 × 10 -12 cm 3 s -1 at v 0 = 0 and 1, respectively. Test calculations for H 2 at j 0 = 1 show that the probabilities can be enhanced by a factor of ~1/3, that is ortho-H 2 seems ~4 times more reactive than para-H 2, The research leading to these result has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement n. 610256 (NANOCOSMOS), the HPC Europa3 Project (INFRAIA-2013- 1-730897) with the support of the EC Research Innovation Action under H2020 Programme and the COST Action CM1401 (Our Astrochemical History). Also, we acknowledge support by the Ministerio de Economía y Competitividad under grants No. FIS2014-52172-C2-2-P and FIS2017-83473-C2-2-P. CINECA is also acknowledged for computer time awarded via the ISCRA programme

In this work, we describe a toolbox to realize and probe synthetic axial gauge fields in engineered Weyl semimetals. These synthetic electromagnetic fields, which are sensitive to the chirality associated with Weyl nodes, emerge due to spatially and temporally dependent shifts of the corresponding Weyl momenta. First, we introduce two realistic models, inspired by recent cold-atom developments, which are particularly suitable for the exploration of these synthetic axial gauge fields. Second, we describe how to realize and measure the effects of such axial fields through center-ofmass observables, based on semiclassical equations of motion and exact numerical simulations. In particular, we suggest realistic protocols to reveal an axial Hall response due to the axial electric field E5, as well as axial cyclotron orbits and chiral pseudo-magnetic effect due to the axial magnetic field B5., SCOPUS: ar.j, info:eu-repo/semantics/published

In modern turbofan engines powering commercial aircraft, the fan is becoming the dominant source of noise at takeoff and landing. Understanding and modeling of the fan noise source, and the interaction of the emitted sound with the airframe, are critical for the design of quiet aircraft. Of particular importance is discrete tone noise radiating from the fan exhaust whose propagation can be shielded by the airframe in advanced aircraft configurations. Current prediction methods for fan noise and its propagation require tremendous amount of computational resources and time. Experiments in large-scale facilities are extremely expensive. There is a need for efficient approaches to experimentally investigate and model fan noise, thus enabling parametric studies that can identify optimal configurations. This study combines novel small-scale experiments with low-order, physics-based modeling of the fan noise source towards achieving the aforementioned goal. The experimental effort entailed the design and construction of a subscale ducted fan rig that includes all the relevant components of the turbofan engine and simulates accurately the sound emission generated by the fan of such engines. The ducted fan includes a nacelle, rotor, and stators, all fabricated using advanced stereolithographic or metal casting methods. It is powered by a high-performance DC motor and achieves rotor tip Mach number of around 0.61 and fan pressure ratio of 1.157, values compatible with the operation of high-bypass turbofan engines. Acoustic diagnostic was conducted inside an anechoic chamber using far-field and near-field phased arrays consisting of 23 microphones. Installation of a rectangular flat plate representing the airframe below the ducted fan recreates complex phenomenon such as scattering off the obstacle, and diffraction around the shield. Addition of the rectangular plate shield generated complex trends in the tonal content and demonstrates the large potential to reduce noise through shielding by the airframe. Tones below the shielding surface were well attenuated, while tones emitted in the aft direction were unchanged. Acquired acoustic data were used to formulate the wavepacket noise model and shielding simulations. The theoretical effort comprises the following steps: (a) extraction of the harmonic content of the measured noise through use of the Vold-Kalman filter; (b) modeling of the aft-emitted fan noise source as a cylindrical wavepacket with azimuthal modes inferred from the Tyler-Sofrin theory; (c) determination of wavepacket shape parameters through least-squares matching of the measured cross-spectral density in the near field and the far field at a given frequency; and (d) propagation and diffraction of the sound from the modeled source using the Boundary Element Method (BEM), with comparisons to measured data. Far-field source parameterization shows that the wavepacket can be modeled as a short cylindrical disturbance surrounding the exit of the nozzle. The resulting modeled sound field captures the most prominent experimental far-field and near-field magnitude and phase relations across numerous microphones. Near-field parameterization expressed similar values to the far-field parameter optimization. This consistency of the cross-spectra in the near and far-field justifies the wavepacket's applicability as an equivalent discrete tone noise source for sound generated by the exhaust of a ducted fan. Numerical shielding predictions using Boundary Element Method (BEM) exhibit complicated changes in far-field noise radiation. Reasonable agreement in average noise reductions is found with experimental data.

Direct numerical simulations (DNS) were used to investigate the effect of frequency bandwidth on the laminar-turbulent transition of wavepackets evolving in a Blasius boundary layer under a total of 18 different combinations of wavepacket frequency, amplitude and bandwidth. Extensive comparisons with linear stability theory (LST) were also performed with a program written to automat- ically calculate the spatial amplification of an ensemble of modes in a wavepacket, enabling the linear and nonlinear aspects of the wavepacket development to be clearly distinguished. Input disturbances that are wide in terms of frequency bandwidth encouraged N-type (Novosibirsk) transition, while narrow-bandwidth disturbances favoured K-type (Klebanoff) transition. However, the initial amplitude and frequency composition of the wavepacket also play an important role in the transition process, with higher-amplitude initial disturbances leading to an increased number of K-type transition events, while frequency compositions that are dominated by linearly damped or slow-growing modes are more likely to transition via the N-route. Moreover, there is a certain preferred frequency of the wavepacket, corresponding to the lower branch point on the neutral stability curve at the disturbance source. The transition process appeared to be most sensitive to changes in bandwidth when the wavepacket is dominated by its preferred frequency.

This dissertation details the development and applications of two innovative types of optical filament-based impulsive Raman spectroscopy: filament-assisted Raman spectroscopy (FAIRS) and spectral-to-temporal amplitude mapping polarization spectroscopy (STAMPS). These techniques provide complimentary vibrational and rotational information on molecular systems of interest. Both are powerful due to their impulsive nature which allows for rapid measurement of entire Raman spectra. However, each type of spectroscopy utilizes the filament in a different manner. The recently reported vibrational technique, referred to as filament-assisted impulsive Raman spectroscopy, employs the pulse shortening and continuum generation of filamentation to impulsively excite a massive vibrational coherence in a molecular system for simultaneous measurement of all the Raman-active modes. In the first half of this dissertation, FAIRS is further developed and applied to a plethora of signature molecules. Radioactive decay signature molecules, including nitrogen oxides, ozone, and ions are detected via FAIR spectroscopy. Concurrent generation and detection of ozone, ionic, and excited-state molecules through filamentation is reported for the first time. Production of these species through the strong field chemistry of filamentation and their subsequent filament-driven excitation is a mark of sensitivity of FAIRS. Spatial studies of combustion species in a natural gas flame are also presented. FAIRS monitors the Raman signal intensities of known reactants and products as a function of vertical flame position. The appearance of combustion products as a function of flame height is also tracked. Spectral fringes overlapping the Raman-active modes are present in all measurements and enable more sensitive detection of low signal intensity species. The results described illustrate the potential of FAIRS for threat sensing applications. The rotational technique, referred to as spectral-to-temporal amplitude mapping polarization spectroscopy, temporally chirps the spectral content of the white-light continuum generated during filamentation to map the transient rotational rivals that are impulsively excited by a short pump pulse. In the second half of this dissertation, the initial development and testing, followed by the applications of STAMPS are described. STAMPS proves successful in mapping the rotational wavepacket rephasing of simple linear molecules, including nitrogen, oxygen, and carbon dioxide, as well as the more complicated asymmetric top molecules, ethylene and methanol. The application of STAMPS to the detection of nitrogen oxides and nitrous oxide, which are considered signatures of multiple threat substances and events, is demonstrated. A pressure study of nitrous oxide reveals dephasing effects as a function of time and pressure. These preliminary results also indicate the potential of STAMPS for hazard sensing applications.

Femtosecond time-resolved photoelectron spectroscopy is emerging as a useful technique for investigating excited state dynamics in isolated polyatomic molecules. The sensitivity of photoelectron spectroscopy to both electronic configurations and vibrational dynamics makes it well suited to the study of ultrafast nonadiabatic processes. We review the conceptual interpretation of wavepacket dynamics experiments, emphasizing the role of the final state. We discuss the advantages of the molecular ionization continuum as the final state in polyatomic wavepacket experiments and show how the electronic structure of the continuum can be used to disentangle electronic from vibrational dynamics. We illustrate these methods with examples from diatomic wavepacket dynamics, internal conversion in polyenes and polyaromatic hydrocarbons, excited state intramolecular proton transfer, and azobenzene photoiosomerization dynamics., Copyright c 2003 by Annual Reviews. All rights reserved

The mechanism of the charge separation and stabilization of separated charges was studied using the femtosecond absorption spectroscopy. It was found that nuclear wavepacket motions on potential energy surface of the excited state of the primary electron donor P* leads to a coherent formation of the charge separated states P(+)B(A)(-), P(+)H(A)(-) and P(+)H(B)(-) (where B(A), H(B) and H(A) are the primary and secondary electron acceptors, respectively) in native, pheophytin-modified and mutant reaction centers (RCs) of Rhodobacter sphaeroides R-26 and in Chloroflexus aurantiacus RCs. The processes were studied by measurements of coherent oscillations in kinetics at 890 and 935 nm (the stimulated emission bands of P*), at 800 nm (the absorption band of B(A)) and at 1020 nm (the absorption band of B(A)(-)) as well as at 760 nm (the absorption band of H(A)) and at 750 nm (the absorption band of H(B)). It was found that wavepacket motion on the 130-150 cm(-1) potential surface of P* is accompanied by approaches to the intercrossing region between P* and P(+)B(A)(-) surfaces at 120 and 380 fs delays emitting light at 935 nm (P*) and absorbing light at 1020 nm (P(+)B(A)(-)). In the presence of Tyr M210 (Rb. sphaeroides) or M195 (C. aurantiacus) the stabilization of P(+)B(A)(-) is observed within a few picosseconds in contrast to YM210W. At even earlier delay (approximately 40 fs) the emission at 895 nm and bleaching at 748 nm are observed in C. aurantiacus RCs showing the wavepacket approach to the intercrossing between the P* and P(+)H(B)(-) surfaces at that time. The 32 cm(-1) rotation mode of HOH was found to modulate the electron transfer rate probably due to including of this molecule in polar chain connecting P(B) and B(A) and participating in the charge separation. The mechanism of the charge separation and stabilization of separated charges is discussed in terms of the role of nuclear motions, of polar groups connecting P and acceptors and of proton of OH group of TyrM210.

The excitation of bacterial reaction centers (RCs) at 870 nm by 30 fs pulses induces the nuclear wavepacket motions on the potential energy surface of the primary electron donor excited state P*, which lead to the fs oscillations in stimulated emission from P* [M.H. Vos, M.R. Jones, C.N. Hunter, J. Breton, J.-C. Lambry and J.-L. Martin (1994) Biochemistry 33, 6750–6757] and in Q Y absorption band of the primary electron acceptor, bacteriochlorophyll monomer B A [A.M. Streltsov, S.I.E. Vulto, A.Y. Shkuropatov, A.J. Hoff, T.J. Aartsma and V.A. Shuvalov (1998) J. Phys. Chem. B 102, 7293–7298] with a set of fundamental frequencies in the range of 10–300 cm −1 . We have found that in pheophytin-modified RCs, the fs oscillations with frequency around 130 cm −1 observed in the P*-stimulated emission as well as in the B A absorption band at 800 nm are accompanied by remarkable and reversible formation of the 1020 nm absorption band which is characteristic of the radical anion band of bacteriochlorophyll monomer B A − . These results are discussed in terms of a reversible electron transfer between P* and B A induced by a motion of the wavepacket near the intersection of potential energy surfaces of P* and P + B A − , when a maximal value of the Franck–Condon factor is created.

In any quantum dynamics method that approximates wave functions as a linearly combined basis set, non-orthogonality can be is a problem. It has been proven in previous studies that, by using the most standard form of Matching Pursuit in combination with a Gaussian wave packet ansatz, exact quantum-mechanical correspondence can be obtained for particle tunneling in one and two dimensions. This study is an attempt to prove that this approach can be generally applicable to systems of arbitrary dimension propagating with an an-harmonic potential, and that adaptive initial state sampling can be used to make the method even more computationally efficient.

A multiconfiguration time-dependent Hartree method oriented toward calculations of a non-Born-Oppenheimer nature has been applied to the calculation of the dynamical properties of a confined H atom. The calculation is fully six-dimensional and does not take into account constraints arising from linear or angular momentum conservation. The orbital evolution is monitored and the energy level spectrum of the system, as well as the dependence of the results on the decomposition of the Hamiltonian and on the correlation between radial degrees of freedom, is determined. A multiconfiguration time-dependent Hartree method oriented toward calculations of a non-Born-Oppenheimer nature has been applied to the calculation of the dynamical properties of a confined H atom. The calculation is fully six-dimensional and does not take into account constraints arising from linear or angular momentum conservation. The orbital evolution is monitored and the energy level spectrum of the system, as well as the dependence of the results on the decomposition of the Hamiltonian and on the correlation between radial degrees of freedom, is determined. © 2012 Wiley Periodicals, Inc.

This work is dealing with quantum-mechanical reaction dynamics. An adaptive basis representation of the wavefunction (proDG) is further developed and combined with a new type of basis functions and the collocation method. In this method basis functions only exist at grid points where they contribute significantly to the complete wavepacket. The second part of the work is dealing with applications. Besides a project which takes the potential energy hyper surface as many-body decomposition and can be accessed as an analytical fit by the dynamics program, two photo-chemical reactions (cyclohexadiene ring-opening and E-Z-isomerization of a briged azobenzene derivative) are investigated. Good agreement with experimental data could be achieved. All calculations were carried out using the universal quantum-dynamics program MrPropa, which is developed in our group. Diese Arbeit befasst sich mit quantenmechanischer Reaktionsdynamik. Dabei wird eine adaptive Darstellung der Wellenfunktion (proDG) weiterentwickelt und mit neuartigen Basisfunktionen und der Kollokationsmethode kombiniert. In dieser Methode existieren Basisfunktionen nur an Gitterpunkten, an denen sie signifikant zum Gesamtwellenpakt beitragen. Der zweite Teil der Arbeit befasst sich mit Anwendungsrechnungen. Neben einem Projekt, in dem die Potentialenergiehyperfläche als Mehrkörperentwicklung aufgefasst wird und dem Dynamikprogramm als analytischer Fit zur Verfügung steht, werden zwei photochemischen Reaktionen (Ringöffnung von Cyclohexadien und E-Z-Isomerisierung eines überbrückten Azobenzolderivates) untersucht. Dabei konnten gute Übereinstimmungen zu experimentellen Daten erzielt werden. Alle Rechnungen wurden mit dem mit dem universellen, quantenmechanischen Dynamikprogramm MrPropa aus unserer Arbeitsgruppe durchgeführt.

A program that uses the time-dependent wavepacket method to study the motion of structureless particles in a force field of quasi-cylindrical symmetry is presented here. The program utilises cylindrical polar coordinates to express the wavepacket, which is subsequently propagated using a Chebyshev expansion of the Schrodinger propagator. Time-dependent exit flux as well as energy-dependent S matrix elements can be obtained for all states of the particle (describing its angular momentum component along the nanotube axis and the excitation of the radial degree of freedom in the cylinder). The program has been used to study the motion of an H atom across a carbon nanotube.

The motions of a wavepacket in the two coupled potentials studied in this thesis can be classified into either bistable or astable motion according to the wavepacket interference at the curve crossing. Bistable motion, in which the wavepacket performs a coupled oscillation but remains in the same adiabatic and diabatic state, can exist both in bound-bound systems and bound-unbound ones with long time stability. Astable motion, in which the wavepacket at the curve crossing switches between the adiabatic and diabatic states and thus alternates between the two possible turning points in the unforked part of the motion, can only exist in bound-bound systems on a limited time scale. The motion of a wavepacket under bistable interference conditions exhibits all of the features expected if the wavepacket moved in a single anharmonic potential. The revival time can be predicted from the revival times in the corresponding diabatic and adiabatic potentials. The phenomenon was observed not only in model molecular systems but also in the system of the harmonically trapped ion pumped by an external laser field with standing wave spatial profile. In order to study the bias effect of the detector on pump-probe rotational anisotropy measurements, in a specific direction the fluorescence polarization effect was removed by measuring the rovibrational wavepacket with the help of properly oriented polarizer placed in front of the detector. Our results show clearly the necessity to take polarization effects into account in ultrafast pump-probe rotational anisotropy measurements.

The wave packets, both linear and nonlinear (like solitons) signals described by a complex time-dependent function, are mapped onto positive probability distributions (tomograms). The quasidistributions, wavelets, and tomograms are shown to have an intrinsic connection. The analysis is extended to signals obeying to the von Neumann-like equation. For solitons (nonlinear signals) obeying the nonlinear Schrödinger equation, the tomographic probability representation is introduced. It is shown that in the probability representation the soliton satisfies a nonlinear generalization of the Fokker–Planck equation. Solutions to the Gross–Pitaevskii equation corresponding to solitons in a Bose–Einstein condensate are considered.

The fine grain parallelizzation of a code performing the time propagation of a wavepacket using a Discrete Variable approach is discussed. To this end a Task Farm model has been implemented. Performances obtained using MPI and the recently proposed skeleton based coordination language ASSIST-CL are compared.

We study the nonlinear energy transfer around the peak of the spectrum of surface gravity waves by taking into account nonhomogeneous effects. In the narrow-banded approximation the kinetic equation resulting from a nonhomogeneous wave field is a Vlasov-Poisson type equation which includes at the same time the random version of the Benjamin-Feir instability and the Landau damping phenomenon. We analytically derive the values of the Phillips' constant $\alpha$ and the enhancement factor $\gamma$ for which the narrow-banded approximation of the JONSWAP spectrum is unstable. By performing numerical simulations of the nonlinear Schr\"{o}dinger equation we check the validity of the prediction of the related kinetic equation. We find that the effect of Landau damping is to suppress the formation of coherent structures. The problem of predicting freak waves is briefly discussed., Comment: 4 pages, 3 figures

The main theme covered in this thesis is experimentalstudies of quantum dynamics and coherent control in homonuclearalkali diatomic molecules by ultrafast laser spectroscopy iththe implementation of pump-probe techniques. A series of experiments have been performed on the Rb2molecules in a molecular beam as well as in a thermal oven. Thereal-time molecular quantum dynamics of the predissociatingelectronically excited D(3)1Πu state of Rb2, which couples to/intersects several otherneighbouring states, is investigated using wavepackets. Thepredissociation of the D state, explored by this wavepacketmethod, arises from two independent states, the (4)3Σu+and (1)3∆u, for which the second corresponds to a much fasterdecay channel above a sharp energy threshold around 430 nm. Thelifetime of the D state above the energy threshold is obtained,τ ≈ 5 ps, by measuring the decay time of thewavepacket in a thermal oven. Further experimentalinvestigation performed in a molecular beam together withquantum calculations of wavepacket dynamics on the D state haveexplored new probe channels of wavepacket evolution: theD′(3)1Σu+ channel, which exhibits vibrational motionin a shelf state and the (4)3Σu+ channel, where direct build-up of thewavefunction is observed due to its spin-orbit oupling to the Dstate. The real-time quantum dynamics of wavepackets confined totwo bound states, A1Σu+(0u+) and b3Πu(0u+), have been studied by experiment andcalculations. It is shown that these two states are fullycoupled by spin-orbit interaction, characterised by itsintermediate strength. The intermediate character of thedynamics is established by complicated wavepacket oscillationatterns and a value of 75 cm-1is estimated for the coupling strength at thestate crossing. The experiments on the Li2molecule are performed by coherent control ofrovibrational molecular wavepackets. First, the Deutsch-Jozsaalgorithm is experimentally demonstrated for three-qubitfunctions using a pure coherent superposition of Li2rovibrational eigenstates. The function’scharacter, either constant or balanced, is evaluated by firstimprinting the function, using a phase-tailored femtosecond(fs) pulse, on a coherent superposition of the molecularstates, and then projecting the superposition onto an ionicfinal state using a second fs pulse at a specific delay time.Furthermore, an amplitude-tailored fs pulse is used to exciteselected rovibrational eigenstates and collision induceddephasing of the wavepacket signal, due to Li2-Ar collisions, is studied experimentally. Theintensities of quantum beats decaying with the delay time aremeasured under various pressures and the collisional crosssections are calculated for each well-defined rovibrationalquantum beat, which set the upper limitsfor ure dephasingcross sections. Keywords:Ultrafast laser spectroscopy, pump-probetechnique, predissociation, wavepacket, pin-orbit interaction,coherent control, (pure) dephasing NR 20140805