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Bibliographie DIR
 
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2019
"Real-time observation of X-ray-induced intramolecular and interatomic electronic decay in CH2I2"
Fukuzawa H, Takanashi T, Kukk E, Motomura K, Wada S-i, Nagaya K, Ito Y, Nishiyama T, Nicolas C, Kumagai Y, Iablonskyi D, Mondal S, Tachibana T, You D, Yamada S, Sakakibara Y, Asa K, Sato Y, Sakai T, Matsunami K, Umemoto T, Kariyazono K, Kajimoto S, Sotome H, Johnsson P, Schöffler MS, Kastirke G, Kooser K, Liu X-J, Asavei T, Neagu L, Molodtsov S, Ochiai K, Kanno M, Yamazaki K, Owada S, Ogawa K, Katayama T, Togashi T, Tono K, Yabashi M, Ghosh A, Gokhberg K, Cederbaum LS, Kuleff AI, Fukumura H, Kishimoto N, Rudenko A, Miron C, Kono H and Ueda K, Nature Communications., Vol. 10(1), pp. 2186, (2019).
Abstract: The increasing availability of X-ray free-electron lasers (XFELs) has catalyzed the development of single-object structural determination and of structural dynamics tracking in real-time. Disentangling the molecular-level reactions triggered by the interaction with an XFEL pulse is a fundamental step towards developing such applications. Here we report real-time observations of XFEL-induced electronic decay via short-lived transient electronic states in the diiodomethane molecule, using a femtosecond near-infrared probe laser. We determine the lifetimes of the transient states populated during the XFEL-induced Auger cascades and find that multiply charged iodine ions are issued from short-lived (~20 fs) transient states, whereas the singly charged ones originate from significantly longer-lived states (~100 fs). We identify the mechanisms behind these different time scales: contrary to the short-lived transient states which relax by molecular Auger decay, the long-lived ones decay by an interatomic Coulombic decay between two iodine atoms, during the molecular fragmentation.
BibTeX:
@article{Fukuzawa2019,
  author = {Fukuzawa, Hironobu and Takanashi, Tsukasa and Kukk, Edwin and Motomura, Koji and Wada, Shin-ichi and Nagaya, Kiyonobu and Ito, Yuta and Nishiyama, Toshiyuki and Nicolas, Christophe and Kumagai, Yoshiaki and Iablonskyi, Denys and Mondal, Subhendu and Tachibana, Tetsuya and You, Daehyun and Yamada, Syuhei and Sakakibara, Yuta and Asa, Kazuki and Sato, Yuhiro and Sakai, Tsukasa and Matsunami, Kenji and Umemoto, Takayuki and Kariyazono, Kango and Kajimoto, Shinji and Sotome, Hikaru and Johnsson, Per and Schöffler, Markus S. and Kastirke, Gregor and Kooser, Kuno and Liu, Xiao-Jing and Asavei, Theodor and Neagu, Liviu and Molodtsov, Serguei and Ochiai, Kohei and Kanno, Manabu and Yamazaki, Kaoru and Owada, Shigeki and Ogawa, Kanade and Katayama, Tetsuo and Togashi, Tadashi and Tono, Kensuke and Yabashi, Makina and Ghosh, Aryya and Gokhberg, Kirill and Cederbaum, Lorenz S. and Kuleff, Alexander I. and Fukumura, Hiroshi and Kishimoto, Naoki and Rudenko, Artem and Miron, Catalin and Kono, Hirohiko and Ueda, Kiyoshi},
  title = {Real-time observation of X-ray-induced intramolecular and interatomic electronic decay in CH2I2},
  journal = {Nature Communications},
  year = {2019},
  volume = {10},
  number = {1},
  pages = {2186},
  url = {https://doi.org/10.1038/s41467-019-10060-z},
  doi = {10.1038/s41467-019-10060-z}
}
Song S, Ding B, Xu W, Nicolas C, Patanen M, Nandi S, Bozek J, Miron C, Xiao Z et Liu X-J (2019), "Sequential electron emission and nuclear dissociation after the O 1s → (4Σ-u )4pσ excitation in O2 molecules", Physical Review A., Feb, 2019. Vol. 99, pp. 022511. American Physical Society.
Abstract: When an electron is resonantly excited from a core orbital to a Rydberg one in a molecule, complex multitime-scale multistep processes are triggered. By using a high-resolution energy-resolved coincidence between Auger electron and ions, we identified the sequences of processes following the spectator Auger decays induced by K-shell excitation in O2. The first step of the spectator Auger decay can end up to a few metastable O2+ states which autoionize into stable O22+. However, the majority of O2+ states are dissociative. They evolve into several dissociation limits with complex crossings between potential-energy curves. After the molecular dissociation is finished, the generated fragments can further decay either by fluorescence emission or by autoionization. Interestingly, some electrons are always emitted after molecular dissociation..
BibTeX:
@article{PhysRevA.99.022511,
  author = {Song, Shan and Ding, Bocheng and Xu, Weiqing and Nicolas, Christophe and Patanen, Minna and Nandi, Saikat and Bozek, John and Miron, Catalin and Xiao, Zhisong and Liu, Xiao-Jing},
  title = {Sequential electron emission and nuclear dissociation after the O 1s → (4Σ-u )4pσ excitation in O2 molecules},
  journal = {Phys. Rev. A},
  publisher = {American Physical Society},
  year = {2019},
  volume = {99},
  pages = {022511},
  url = {https://link.aps.org/doi/10.1103/PhysRevA.99.022511},
  doi = {10.1103/PhysRevA.99.022511}
}
"Coulomb implosion of tetrabromothiophene observed under multiphoton ionization by free-electron-laser soft-x-ray pulses"
Kukk E, Myllynen H, Nagaya K, Wada S, Bozek JD, Takanashi T, You D, Niozu A, Kooser K, Gaumnitz T, Pelimanni E, Berholts M, Granroth S, Yokono N, Fukuzawa H, Miron C and Ueda K (2019), Phys. Rev. A., Feb, 2019. Vol. 99, pp. 023411. American Physical Society, 2019
Abstract: Soft-x-ray free-electron-laser pulses were used to create highly charged molecular tetrabromothiophene species by sequential multiphoton ionization from bromine 3d orbitals. The experiment was performed at the SACLA facility in Japan and the products of molecular dissociation were analyzed by means of multicoincidence momentum-resolved ion time-of-flight spectroscopy. Total charge states up to +13 atomic units were produced, creating a particular dissociation pattern for the carbon ions, a Coulomb implosion, due to the concerted forces by the surrounding heavy bromine ions. This behavior was explored both experimentally and by numerical molecular-dynamics simulations and the fingerprints of the Coulomb implosion were identified in both. In simulations, Coulomb implosion was predicted to be highly sensitive to the initial (thermal) motion of the atoms and, after including vibrational motion for several temperatures, good general agreement between the experiment and simulations was found. The agreement with the experiment was further improved by adding charge dynamics to the simulation, according to our point-charge dynamics model with empirical rate constants.
BibTeX:
@article{PhysRevA.99.023411,
  author = {Kukk, E. and Myllynen, H. and Nagaya, K. and Wada, S. and Bozek, J. D. and Takanashi, T. and You, D. and Niozu, A. and Kooser, K. and Gaumnitz, T. and Pelimanni, E. and Berholts, M. and Granroth, S. and Yokono, N. and Fukuzawa, H. and Miron, C. and Ueda, K.},
  title = {Coulomb implosion of tetrabromothiophene observed under multiphoton ionization by free-electron-laser soft-x-ray pulses},
  journal = {Phys. Rev. A},
  publisher = {American Physical Society},
  year = {2019},
  volume = {99},
  pages = {023411},
  url = {https://link.aps.org/doi/10.1103/PhysRevA.99.023411},
  doi = {10.1103/PhysRevA.99.023411}
}
2018
"Photoionization dynamics of cis-dichloroethene from investigation of vibrationally resolved photoelectron spectra and angular distributions"
Powis I, Menzies RC, Holland DMP, Trofimov AB, Skitnevskaya AD, Gromov EV, Antonsson E, Patanen M, Nicolas C and Miron C, The Journal of Chemical Physics. Vol. 149(7), pp. 074305, (2018).
Abstract: The influence of vibronic coupling on the outer valence ionic states of cis-dichloroethene has been investigated by recording photoelectron spectra over the excitation range 19–90 eV using plane polarized synchrotron radiation, for two polarization orientations. The photoelectron anisotropy parameters and electronic state branching ratios derived from these spectra have been compared to theoretical predictions obtained with the continuum multiple scattering approach. This comparison shows that the photoionization dynamics of the à p2B2sub>, B 2A1, C̃ 2A2, and D̃ 2B1 states, all of which are formed through the ejection of an electron from a nominally chlorine lone-pair orbital, exhibit distinct evidence of the Cooper minimum associated with the halogen atom. While retaining a high degree of atomic character, these orbital ionizations nevertheless display clear distinctions. Simulations, assuming the validity of the Born-Oppenheimer and the Franck-Condon approximations, of the X̃ 2B1, à 2B2, and D̃2B1 state photoelectron bands have allowed some of the vibrational structure observed in the experimental spectra to be assigned. The simulations provide a very satisfactory interpretation for the X̃ 2B1 state band but appear less successful for the Ã2B2 and D̃ 2B1 states, with irregularities appearing in both. The B̃ 2A1 and C̃ 2A2 state photoelectron bands exhibit very diffuse and erratic profiles that cannot be reproduced at this level. Photoelectron anisotropy parameters, β, have been evaluated as a function of binding energy across the studied photon energy range. There is a clear step change in the β values of the à 2B2 band at the onset of the perturbed peak intensities, with β evidently adopting the value of the B̃2A1 band β. The D̃ 2B1 band β values also display an unexpected vibrational level dependence, contradicting Franck-Condon expectations. These various behaviors are inferred to be a consequence of vibronic coupling in this system.
BibTeX:
@article{Powis2018,
  author = {Powis, I. and Menzies, R. C. and Holland, D. M. P. and Trofimov, A. B. and Skitnevskaya, A. D. and Gromov, E. V. and Antonsson, E. and Patanen, M. and Nicolas, C. and Miron, C.},
  title = {Photoionization dynamics of cis-dichloroethene from investigation of vibrationally resolved photoelectron spectra and angular distributions},
  journal = {The Journal of Chemical Physics},
  year = {2018},
  volume = {149},
  number = {7},
  pages = {074305},
  url = {https://aip.scitation.org/doi/abs/10.1063/1.5042216},
  doi = {10.1063/1.5042216}
}
"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 and 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 and 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 and 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 and 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 and 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}
}
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