Publications DIR

Bibliographie DIR
 
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2018
"An experimental and theoretical study of the photoelectron spectra of cis-dichloroethene: Valence shell vertical ionization and vibronic coupling in the low-lying cationic states"
Trofimov AB, Powis I, Menzies RC, Holland DMP, Antonsson E, Patanen M, Nicolas C, Miron C, Skitnevskaya AD, Gromov EV et Köppel H, The Journal of Chemical Physics., August, 2018. Vol. 149(7), pp. 074306. American Institute of Physics, (2018).
Abstract: The valence shell photoelectron spectrum of cis-dichloroethene has been studied both experimentally and theoretically. Photoelectron spectra have been recorded with horizontally and vertically plane polarized synchrotron radiation, thereby allowing the anisotropy parameters, characterizing the angular distributions, to be determined. The third-order algebraic-diagrammatic construction approximation scheme for the one-particle Green’s function has been employed to compute the complete valence shell ionization spectrum. In addition, the vertical ionization energies have been calculated using the outer valence Green’s function (OVGF) method and the equation-of-motion coupled-cluster, with single and double substitutions for calculating ionization potentials (EOM-IP-CCSD) model. The theoretical results have enabled assignments to be proposed for most of the structure observed in the experimental spectra, including the inner-valence regions dominated by satellite states. The linear vibronic coupling model has been employed to study the vibrational structure of the lowest photoelectron bands, using parameters obtained from ab initiocalculations. The ground state optimized geometries and vibrational frequencies have been computed at the level of the second-order Møller-Plesset perturbation theory, and the dependence of the ionization energies on the nuclear configuration has been evaluated using the OVGF method. While the adiabatic approximation holds for the  2B1 state photoelectron band, the   2B2  2A1, and   2A2 states interact vibronically and form a complex photoelectron band system with four distinct maxima. The   2B1 and  2B2 states also interact vibronically with each other. The potential energy surface of the  2B1 state is predicted to have a double-minimum shape with respect to the out-of-plane a2 deformations of the molecular structure. The single photoelectron band resulting from this interaction is characterized by a highly irregular structure, reflecting the non-adiabatic nuclear dynamics occurring on the two coupled potential energy surfaces forming a conical intersection close to the minimum of the  2B2 state.
BibTeX:
@article{Trofimov2018,
  author = {Trofimov, A. B. and Powis, I. and Menzies, R. C. and Holland, D. M. P. and Antonsson, E. and Patanen, M. and Nicolas, C. and Miron, C. and Skitnevskaya, A. D. and Gromov, E. V. and Kppel, H.},
  title = {An experimental and theoretical study of the photoelectron spectra of cis-dichloroethene: Valence shell vertical ionization and vibronic coupling in the low-lying cationic states},
  journal = {The Journal of Chemical Physics},
  publisher = {American Institute of Physics},
  year = {2018},
  volume = {149},
  number = {7},
  pages = {074306},
  url = {https://doi.org/10.1063/1.5033425},
  doi = {10.1063/1.5033425}
}
"Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters"
Kumagai Y, Fukuzawa H, Motomura K, Iablonskyi D, Nagaya K, Wada S-i, Ito Y, Takanashi T, Sakakibara Y, You D, Nishiyama T, Asa K, Sato Y, Umemoto T, Kariyazono K, Kukk E, Kooser K, Nicolas C, Miron C, Asavei T, Neagu L, Schöffler MS, Kastirke G, Liu X-j, Owada S, Katayama T, Togashi T, Tono K, Yabashi M, Golubev NV, Gokhberg K, Cederbaum LS, Kuleff AI et Ueda K, Physical Review X., Aug, 2018. Vol. 8, pp. 031034. American Physical Society, (2018).
Abstract: X-ray free-electron lasers (XFELs) made available a new regime of x-ray intensities, revolutionizing the ultrafast structure determination and laying the foundations of the novel field of nonlinear x-ray optics. Although earlier studies revealed nanoplasma formation when an XFEL pulse interacts with any nanometer-scale matter, the formation process itself has never been decrypted and its timescale was unknown. Here we show that time-resolved ion yield measurements combined with a near-infrared laser probe reveal a surprisingly ultrafast population (~ 12 fs), followed by a slower depopulation (~ 250 fs) of highly excited states of atomic fragments generated in the process of XFEL-induced nanoplasma formation. Inelastic scattering of Auger electrons and interatomic Coulombic decay are suggested as the mechanisms populating and depopulating, respectively, these excited states. The observed response occurs within the typical x-ray pulse durations and affects x-ray scattering, thus providing key information on the foundations of x-ray imaging with XFELs.
BibTeX:
@article{PhysRevX.8.031034,
  author = {Kumagai, Yoshiaki and Fukuzawa, Hironobu and Motomura, Koji and Iablonskyi, Denys and Nagaya, Kiyonobu and Wada, Shin-ichi and Ito, Yuta and Takanashi, Tsukasa and Sakakibara, Yuta and You, Daehyun and Nishiyama, Toshiyuki and Asa, Kazuki and Sato, Yuhiro and Umemoto, Takayuki and Kariyazono, Kango and Kukk, Edwin and Kooser, Kuno and Nicolas, Christophe and Miron, Catalin and Asavei, Theodor and Neagu, Liviu and Schöffler, Markus S. and Kastirke, Gregor and Liu, Xiao-jing and Owada, Shigeki and Katayama, Tetsuo and Togashi, Tadashi and Tono, Kensuke and Yabashi, Makina and Golubev, Nikolay V. and Gokhberg, Kirill and Cederbaum, Lorenz S. and Kuleff, Alexander I. and Ueda, Kiyoshi},
  title = {Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters},
  journal = {Phys. Rev. X},
  publisher = {American Physical Society},
  year = {2018},
  volume = {8},
  pages = {031034},
  url = {https://link.aps.org/doi/10.1103/PhysRevX.8.031034},
  doi = {10.1103/PhysRevX.8.031034}
}
"Radiation-Induced Chemical Dynamics in Ar Clusters Exposed to Strong X-Ray Pulses"
Kumagai Y, Jurek Z, Xu W, Fukuzawa H, Motomura K, Iablonskyi D, Nagaya K, Wada S-i, Mondal S, Tachibana T, Ito Y, Sakai T, Matsunami K, Nishiyama T, Umemoto T, Nicolas C, Miron C, Togashi T, Ogawa K, Owada S, Tono K, Yabashi M, Son S-K, Ziaja B, Santra R et Ueda K, Phys. Rev. Lett., Vol. 120(22), pp. 223201. American Physical Society, (2018)
Abstract: We show that electron and ion spectroscopy reveals the details of the oligomer formation in Ar clusters exposed to an x-ray free electron laser (XFEL) pulse, i.e., chemical dynamics triggered by x rays. With guidance from a dedicated molecular dynamics simulation tool, we find that van der Waals bonding, the oligomer formation mechanism, and charge transfer among the cluster constituents significantly affect ionization dynamics induced by an XFEL pulse of moderate fluence. Our results clearly demonstrate that XFEL pulses can be used not only to damage and destroy molecular assemblies but also to modify and transform their molecular structure. The accuracy of the predictions obtained makes it possible to apply the cluster spectroscopy, in connection with the respective simulations, for estimation of the XFEL pulse fluence in the fluence regime below single-atom multiple-photon absorption, which is hardly accessible with other diagnostic tools.
BibTeX:
@article{Kumagai2018,
  author = {Kumagai, Yoshiaki and Jurek, Zoltan and Xu, Weiqing and Fukuzawa, Hironobu and Motomura, Koji and Iablonskyi, Denys and Nagaya, Kiyonobu and Wada, Shin-ichi and Mondal, Subhendu and Tachibana, Tetsuya and Ito, Yuta and Sakai, Tsukasa and Matsunami, Kenji and Nishiyama, Toshiyuki and Umemoto, Takayuki and Nicolas, Christophe and Miron, Catalin and Togashi, Tadashi and Ogawa, Kanade and Owada, Shigeki and Tono, Kensuke and Yabashi, Makina and Son, Sang-Kil and Ziaja, Beata and Santra, Robin and Ueda, Kiyoshi},
  title = {Radiation-Induced Chemical Dynamics in Ar Clusters Exposed to Strong X-Ray Pulses},
  journal = {Phys. Rev. Lett.},
  publisher = {American Physical Society},
  year = {2018},
  volume = {120},
  number = {22},
  pages = {223201},
  url = {https://link.aps.org/doi/10.1103/PhysRevLett.120.223201},
  doi = {10.1103/PhysRevLett.120.223201}
}
"Synchrotron-Radiation-Based Soft X-ray Electron Spectroscopies Applied to Structural and Chemical Characterization of Isolated Species, from Molecules to Nano-objects"
Miron C, Patanen M et Benkoula S , In Synchrotron Radiation in Materials Science. , pp. 321-355. Wiley-VCH Verlag GmbH & Co. KGaA, (2018).
Abstract: With its extended tunability from the IR to hard X-rays and the exceptional spectral brightness offered by the third generation storage rings, synchrotron radiation (SR) has become an invaluable investigation tool. Major methodological developments have been recently undertaken, first applied to simple systems, isolated atoms and molecules - that can be often modeled ab initio - and then extended to the investigation of more and more complex species, up to the soft and hard condensed matter. Here, we present some of the most recent achievements in SR-based soft X-ray electron spectroscopy applied to the structural characterization of isolated species of increasing complexity from molecules to clusters and nanoparticles. Special attention is devoted to very high-resolution studies of free molecules revealing physical phenomena such as electron diffraction and interference effects, as well as detailed information about the potential energy surfaces. Beyond this, we will see how technical progress of SR-based soft X-ray spectroscopy opens new routes to structural studies on freestanding nanosystems. These achievements have only become possible using the new experimental opportunities offered by the most advanced SR facilities.
BibTeX:
@inbook{Miron2018a,
  author = {Miron, Catalin and Patanen, Minna and Benkoula, Safia},
  title = {Synchrotron-Radiation-Based Soft X-ray Electron Spectroscopies Applied to Structural and Chemical Characterization of Isolated Species, from Molecules to Nano-objects},
  booktitle = {Synchrotron Radiation in Materials Science},
  publisher = {Wiley-VCH Verlag GmbH & Co. KGaA},
  year = {2018},
  pages = {321--355},
  url = {http://dx.doi.org/10.1002/9783527697106.ch10},
  doi = {10.1002/9783527697106.ch10}
}
2017
"Electronic-state interference in the C1s excitation and decay of methyl chloride studied by angularly resolved Auger spectroscopy"
Nandi S, Nicolas C, Artemyev AN, Novikovskiy NM, Miron C, Bozek JD et Demekhin PV , Physical Review A., Nov, 2017. Vol. 96, pp. 052501. American Physical Society, (2017).
Abstract: Resonant Auger (RA) decay spectra of carbon 1s 1 s excited CH3Cl CH 3 Cl molecules are recorded with angular resolution using linearly polarized synchrotron radiation. The selected photon energies corresponding to the C 1s8a1 1 s 8 a 1 core to lowest unoccupied molecular orbital and C 1s4sa1 1 s 4 s a 1 , 4pe 4 p e , and 4pa1 4 p a 1 core to Rydberg excitations of methyl chloride are used and electrons in the binding energy range of 11–37 eV are detected. The vibrationally unresolved RA electron angular distributions, recorded for participator Auger transitions populating the X X , A A , B B , and C C states of the CH3Cl+ CH 3 Cl + ion, exhibit strong variations across the selected electronic resonances. These observations are interpreted with the help of ab initio electronic structure and dynamics calculations, which account for electronic-state interference between the direct and different resonant ionization pathways. For spectator transitions, the theory predicts almost isotropic angular distributions with moderate changes of β parameters around zero, which is in agreement with the experimental observations.
BibTeX:
@article{PhysRevA.96.052501,
  author = {Nandi, S. and Nicolas, C. and Artemyev, A. N. and Novikovskiy, N. M. and Miron, C. and Bozek, J. D. and Demekhin, Ph. V.},
  title = {Electronic-state interference in the C1s excitation and decay of methyl chloride studied by angularly resolved Auger spectroscopy},
  journal = {Phys. Rev. A},
  publisher = {American Physical Society},
  year = {2017},
  volume = {96},
  pages = {052501},
  url = {https://link.aps.org/doi/10.1103/PhysRevA.96.052501},
  doi = {10.1103/PhysRevA.96.052501}
}
List created by JabRef on 10/11/2017.
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