Peer-reviewed Publications |
Blancard C., Cubaynes D., Guilbaud S., & and Bizau J.-M. (2017). L -shell photoionization of Mn 5+ to Mn 8+ ions. PHYSICAL REVIEW A, 96, 013410.
Résumé: Resonant photoionization cross sections of Mnn+ (n=5 to 8) ions are measured in absolute values in the photon energy range of the 2p→3d transitions (645-690eV)using a merged-beams setup at the SOLEIL synchrotron radiation facility. The experimental cross sections are compared to calculations we performed using a multiconfiguration Dirac-Fock code and the opas code dedicated to radiative opacity calculations of hot and dense plasmas. Both calculations reproduce the measurements well.
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Chamakhi, R., Puthumpally-Joseph, R., Telmini, M., & Charron, E. (2017). Extracting spectroscopic molecular parameters from short pulse photo-electron angular distributions. J. Chem. Phys., 147(14), 144304.
Résumé: Using a quantum wave packet simulation including the nuclear and electronic degrees of freedom, we investigate the femtosecond and picosecond energy- and angle-resolved photoelectron spectra of the E(Sigmag+1) electronic state of Li2. We find that the angular distributions of the emitted photoelectrons depend strongly on the pulse duration in the regime of ultrashort laser pulses. This effect is illustrated by the extraction of a time-dependent asymmetry parameter whose variation with pulse duration can be explained by an incoherent average over different ion rotational quantum numbers. We then derive for the variation of the asymmetry parameter a simple analytical formula, which can be used to extract the asymptotic CW asymmetry parameters of individual transitions from measurements performed with ultra-short pulses.
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Douix S., Duflot D., Cubaynes D., Bizau J.M., & and Giuliani A. (2017). Photoionization of the Buckminsterfullerene Cation. J. Phys. Chem. Lett, 8(1), 7–12.
Résumé: Photoionization of a buckminsterfullerene ion is investigated using an ion trap and a merged beam setup coupled to synchrotron radiation beamlines and compared to theoretical calculations. Absolute measurements derived from the ion trap experiment allow discrepancies concerning the photoionization cross section of C60+ to be solved.
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Gonon, B., Perveaux, A., Gatti, F., Lauvergnat, D., & Lasorne, B. (2017). On the applicability of a wavefunction-free, energy-based procedure for generating first-order non-adiabatic couplings around conical intersections. Journal Of Chemical Physics, 147(11), 114114.
Résumé: The primal definition of first-order non-adiabatic couplings among electronic states relies on the knowledge of how electronic wave functions vary with nuclear coordinates. However, the non-adiabatic coupling between two electronic states can be obtained in the vicinity of a conical intersection from energies only, as this vector spans the branching plane along which degeneracy is lifted to first order. The gradient difference and derivative coupling are responsible of the two-dimensional cusp of a conical intersection between both potential-energy surfaces and can be identified to the non-trivial eigenvectors of the second derivative of the square energy difference, as first pointed out in Koppel and Schubert [Mol. Phys. 104(5-7), 1069 (2006)]. Such quantities can always be computed in principle for the cost of two numerical Hessians in the worst-case scenario. Analytic-derivative techniques may help in terms of accuracy and efficiency but also raise potential traps due to singularities and ill-defined derivatives at degeneracies. We compare here two approaches, one fully numerical, the other semianalytic, where analytic gradients are available but Hessians are not, and investigate their respective conditions of applicability. Benzene and 3-hydroxychromone are used as illustrative application cases. It is shown that non-adiabatic couplings can thus be estimated with decent accuracy in regions of significant size around conical intersections. This procedure is robust and could be useful in the context of on-the-fly non-adiabatic dynamics or be used for producing model representations of intersecting potential energy surfaces with complete obviation of the electronic wavefunctions. Published by AIP Publishing.
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Jaouadi, A., Lefebvre, R., & Atabek, O. (2017). Vibrational-ground-state zero-width resonnaces for laser filtration: An extended semiclassical analysis. Phys. Rev. A, 95, 063409.
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Khalal M. A., L. P., Andric L., Palaudoux J., Penent F., Bučar K., Žitnik M., Püttner R., Jänkälä K., Cubaynes D., Guilbaud S., and Bizau J.-M. (2017). 4d -inner-shell ionization of Xe+ ions and subsequent Auger decay. PHYSICAL REVIEW A, 96, 013412.
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Khalal M.A., S. J., Jänkälä K., Huttula S-M, Huttula M, Bizau J-M, Cubaynes D., Guilbaud S., Ito K., Andric L., Feng J., Lablanquie P., Palaudoux J. and Penent F. (2017). Multielectron spectroscopy: energy levels of K n+ and Rb n+ ions (n = 2, 3, 4). Journal of Physics B: Atomic, Molecular and Optical Physics, 50(22), 225003.
Résumé: A magnetic bottle time-of-flight spectrometer has been used to perform spectroscopy of K n+ and Rb n+ states with ionization degrees n of 2, 3 and 4. Energy levels are directly measured by detecting in coincidence the n electrons that are emitted as a result of single photon absorption. Experimental results are compared with the energies from the NIST atomic database and ab initio multiconfiguration Dirac–Fock calculations. Previously unidentified 3p 4(3P)3d 1 4D energy levels of K2+ are assigned.
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Lablanquie P., K. M. A., Andric L., Palaudoux J., Penent F., Bizau J-M, Cubaynes D., Jänkälä K., Hikosaka Y., Ito K., Bučar K., Žitnikg M. (2017). Multi-electron coincidence spectroscopy: Triple Auger decay of Ar 2p and 2s holes. Journal of Electron Spectroscopy and Related Phenomena, 220, 125–132.
Résumé: The detailed study of single photon multiple ionization processes requires the detection in coincidence of all the electrons emitted from the same ionization event. The advent of magnetic bottle experiments made possible the development of this multi-electron coincidence spectroscopy. First we will briefly review the achievements of this technique. Then we will illustrate more specifically its high sensitivity taking as an example the decay by emission of three Auger electrons of 2p and 2s holes in argon. Our results show that the processes are completely different depending on the initial core hole: the three Auger electrons are emitted dominantly in a simultaneous path for the 2p case, but in cascade for the 2s one.
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Le Marec, A., Larroche, O., & Klisnick, A. (2017). Linear autocorrelation of partially coherent extreme-ultraviolet lasers: a quantitative analysis. Optics Letters, 42(23), 4958–4961.
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Leclerc, A., Viennot, D., Jolicard, G., Lefebvre, R., & Atabek, O. (2017). Exotic states in the strong field control of H2+ dissociation dynamics: From exceptional points to zero width resonances. J. Phys. B, 50, 234002.
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Lefebvre, R. (2017). Factorisation of zero-width resonance wave functions. Molecular Physics, 115(15-16), 1966–1970.
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Mendive-Tapia, D., Firmino, T., Meyer, H. D., & Gatti, F. (2017). Towards a systematic convergence of Multi-Layer (ML) Multi-Configuration Time-Dependent Hartree nuclear wavefunctions: The ML-spawning algorithm. CHEMICAL PHYSICS, 482, 113–123.
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Muzas, A. S., del Cueto, M., Gatti, F., Somers, M. F., Kroes, G. J., Martin, F., & Diaz, C. (2017). H-2/LiF(001) diffractive scattering under fast grazing incidence using a DFT-based potential energy surface. Physical Review B, 96(20), 205432.
Résumé: Grazing incidence fast molecule diffraction (GIFMD) has been recently used to study a number of surfaces, but this experimental effort has not been followed, to present, by a subsequent theoretical endeavor. Aiming at filling this gap, in this work, we have carried out GIFMD simulations for the benchmark system H-2/ LiF(001). To perform our study, we have built a six-dimensional potential energy surface (6D-PES) by applying a modified version of the corrugation reducing procedure (CRP) to a set of density functional theory (DFT) energies. Based on this CRP interpolated PES, we have conducted quantum dynamics calculations using both the multiconfiguration time-dependent Hartree and the time-dependent wave packet propagation methods. We have compared the results of our GIFMD simulations with available experimental spectra. From this comparison, we have uncovered a prominent role of the interaction between the quadrupole moment of H-2 and the electric field associated with LiF(001) for specific incidence crystallographic directions. We show that, on the one hand, the molecule's initial rotation strongly affects its diffractive scattering and, on the other hand, the scattering is predominantly rotationally elastic over a wide range of incidence conditions typical for GIFMD experiments.
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Ndengue, S., Dawes, R., Gatti, F., & Meyer, H. D. (2017). Atom-triatom rigid rotor inelastic scattering with the MultiConfiguration Time Dependent Hartree approach. Chemical Physics Letters, 668, 42–46.
Résumé: The inelastic scattering between a rigid rotor triatomic molecule and an atom is described within the frame of the MultiConfiguration Time dependent Hartree (MCTDH) method. Sample calculations are done on the H2O-Ar system for which a flexible 6D PES (used here in the rigid rotor approximation) has been recently computed in our group and will be presented separately. The results are compared with corresponding time independent calculations using the Arthurs and Dalgarno approach and confirm as expected the equivalence of the two methods. (C) 2016 Elsevier B.V. All rights reserved.
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Nguyen-Dang, T. T., Peters, M., Viau-Trudel, J., Couture-Bienvenue, E., Puthumpally-Joseph, R., Charron, E., & Atabek, O. (2017). Laser-induced electron diffraction: alignment defects and symmetry breaking. Molecular Physics, 115(15-16), 1934–1943.
Résumé: The fringe pattern that allows geometrical and orbital structure information to be extracted from LIED (laser-induced electron diffraction) spectra of symmetric molecules is shown to reflect a symmetry conservation principle. We show that under a field polarisation which preserves certain symmetry elements of the molecule, the symmetry character of the initial wave function is conserved during its time-evolution. We present a symmetry analysis of a deviation from a perfect alignment by decomposing the field into a major, symmetry-determining part, and a minor, symmetry-breaking part. This decomposition leads to a corresponding factorisation of the time-evolution operator. The formalism is applied to the analysis of the robustness of LIED readings and inversions with respect to deviations from a perfect perpendicular and parallel alignment of a symmetric ABA triatomic molecule. The results indicate a particularly strong stability of the type of LIED spectra associated with the perpendicular alignment situation.
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Poullain, S. M., Cireasa, R., Cornaggia, C., Simon, M., Marin, T., Guillemin, R., Houver, J. C., Lucchese, R. R., & Dowek, D. (2017). Spectral dependence of photoemission in multiphoton ionization of NO2 by femtosecond pulses in the 375-430 nm range. Physical Chemistry Chemical Physics, 19(33), 21996–22007.
Résumé: We investigate the multiphoton ionization of NO2 using tunable (430-375 nm) femtosecond pulses and photoelectron-photoion coincidence momentum spectroscopy. In order to understand the complex electronic and nuclear photodynamics at play following absorption of three to five photons, we also report extended photoionization calculations using correlated targets and coupled channels. Exploring the multiphoton dissociative ionization (MPDI) and multiphoton ionization (MPI) processes over such a broad energy range enables us to lend further support to our work carried out around 400 nm of a femtosecond laser [S. Marggi Poullain et al., J. Phys. B: At., Mol. Opt. Phys., 2014, 47, 124024]. Two excitation energy regions are identified and discussed in terms of the proposed reaction pathways, highlighting the significant role of Rydberg states, such as the [R*(6a(1))(-1), 3p sigma] Rydberg state, in the NO2 multiphoton excitation and photoionization. These new results support our previous assumption that different bent and linear geometries of the NO2 +(X-1 Sigma(g)) ionic state contribute to the MPDI and MPI, consistent with the reported calculations which reveal an important vibronic coupling characterizing the photoemission. Remarkably, the strong anisotropy of the recoil frame photoelectron angular distribution (RFPAD) previously observed at 400 nm appears as a fingerprint across the whole explored photon energy range.
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Puthumpally-Joseph R., Mangaud E., Desouter-Lecomte M., Atabek O., & Sugny D. (2017). Towards laser control of open quantum systems: Memory effects. Mol. Phys., 115, 1944.
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Puthumpally-Joseph, R., Viau-Trudel, J., Peters, M., Nguyen-Dang, T. T., Atabek, O., & Charron, E. (2017). Laser-induced electron diffraction: inversion of photo-electron spectra for molecular orbital imaging. Molecular Physics, 115(15-16), 1889–1897.
Résumé: In this paper, we discuss the possibility of imaging molecular orbitals from photoelectron spectra obtained via laser -induced electron diffraction in linear molecules. This is an extension of our recent work to the case of the HOMO-1 orbital of the carbon dioxide molecule. We show that such an imaging technique has the potential to image molecular orbitals at different internuclear distances in a sub-femtosecond time scale and with a resolution of a fraction of an Angström.
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Sukharev, M., & Charron, E. (2017). Molecular plasmonics: The role of rovibrational molecular states in exciton-plasmon materials under strong-coupling conditions. Phys. Rev. B, 95, 115406.
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Chapitres de Livres |
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Gatti F., & Lasorne B., M. H. - D., and Nauts A. (2017). Quantum Dynamics: Application in Chemistry. In Lectures Notes in Chemistry, Springer, Heidelberg (Vol. Book 98).
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