Effect of the Cl2p core orbital excitation on the nuclear dynamics of the three dichloroethylene isomers

Céolin, Denis; Travnikova, Oksana; Zhaorigetu, Bao; Kivimäki, A.; Carniato, S.; Piancastelli, M. N.

doi:10.1016/j.elspec.2010.11.002

Cited by 8 publications

(4 citation statements)

References 31 publications

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“…In Figure , the vertical blue lines mark the positions of the Cl and Br atomic fragment Auger lines, which lie at constant E k and show nondispersive behavior with the excitation energy. , The presence of sharp distinct features at these E k in Figure is a signature of the UFD process occurring in the corresponding core-excited states. Moreover, the overall shape of the RPE spectra, shown in Figure b for the region E k = 175 – 183 eV, resembles the RPE spectra of other chlorinated hydrocarbons (such as C 2 H 2 Cl 2 or CH 3 Cl), where UFD has been identified before. , …”

supporting

confidence: 58%

“…Following similar considerations, in the case of larger molecules, such as dichloroethenes (C 2 H 2 Cl 2 ) or 1-bromo-2-chloroethane, the dissociation is expected to be even slower than in Cl 2 if it proceeds strictly along C–Cl or C–Br bond coordinates . Despite this prediction, the signatures of UFD were recently observed for Cl2p core-excited dichloroethenes . The point-mass model also failed to explain the shorter time scales observed for the strong-field photodissociation of CH 2 Br 2 .…”

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confidence: 93%

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On Routes to Ultrafast Dissociation of Polyatomic Molecules

Travnikova

Kimberg

Flammini

et al. 2013

J. Phys. Chem. Lett.

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Dissociation pathways for complex polyatomic molecules can sometimes be obscure due to the multitude of degrees of freedom involved. Here, we suggest the description of a dissociation mechanism implying multimode dynamics on the barrierless potential energy surface. The mechanism is elaborated from the X-ray spectroscopic analysis of the ultrafast nuclear motion in core−shell excited molecules. We infer that in large molecules, dissociation pathways are observed to deviate from the two-body dissociation coordinate due to the internal motion of light linkages, which alters dissociation rates and may yield heavy products on very short time scales. The mechanism is exemplified with the case of 1-bromo-2-chloroethane, where the rotation of the C 2 H 4 -moiety leads to the dissociation of C−Cl or C−Br bonds in Cl2p or Br3d core-excited states, whose lifetimes last only ∼7 fs.

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supporting

confidence: 58%

mentioning

confidence: 93%

On Routes to Ultrafast Dissociation of Polyatomic Molecules

Travnikova

Kimberg

Flammini

et al. 2013

J. Phys. Chem. Lett.

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“…Direct valence ionization, core-level excitation, and ionization of molecules are attractive means for the study of the dissociation dynamics. In the case of core-level studies, the choice of the photon energy makes it possible to excite specific resonances neighboring a selected inner-shell edge, affording to a selective fragmentation. − More specifically, the study on the competition between Auger decay and the so-called ultrafast dissociation − in neutral highly excited molecular species is of particular interest, giving rise to a transfer of an electron from an inner shell to an unoccupied valence orbital or to the ejection of one or more electrons into the continuum. Core excitation and ionization of molecules using soft X-rays give rise to core–hole creation with lifetimes of the order of a few femtoseconds, about the time it takes for the nuclei to shift substantially their positions away from their equilibrium configuration.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of larger molecules, such as dichloroethenes (C 2 H 2 Cl 2 ), the dissociation is expected to be slower than in Cl 2 if it takes place strictly along C–Cl bond coordinates. Nevertheless, signatures of ultrafast fragmentation were detected for Cl 2p core-excited dichloroethenes …”

Section: Introductionmentioning

confidence: 99%

Fragmentation of Valence and Core–Shell (Cl 2p) Excited C₂Cl₄ Molecule

et al. 2017

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The dynamics of the photofragmentation pathways of tetrachloroethylene with photon energies from 15 up to 250 eV encompassing the Cl 2p edge is presented. In order to distinguish the fragmentation channels, the ionic fragments were separated according to their mass-to-charge ratio, measured in coincidence with the photoelectrons, and collected as a function of the incident photon energy. Distinct minima or maxima are found in the partial ion yield in the region between 40 and 50 eV. These features are believed to be associated with the Cooper minimum which results from a molecular orbital with a strong atomic 3p subshell character. In the shallow core region, some fragmentation patterns are considered in terms of fast fragmentation of the CCl molecule, despite the heavy mass of its fragments. In the present case, the fast fragmentation is favored by the very strong antibonding character of the LUMO, understandable in the frame of the core equivalent model for halogen-containing molecules. In addition, ab initio calculations were performed to obtain states at the Cl 2p edge. Singlet and triplet states at the Cl 2p edge of the CCl molecule, corresponding to the Cl(2p → 9b*) and Cl(2p → 8b*) transitions, were calculated in order to form a basis set of molecular states from which the spin-orbit splitting can be inferred. Multiconfigurational self-consistent field (MCSCF) calculation followed by multireference configuration interaction (MRCI) was the method chosen to establish a set of singlet and triplet states at the 2p excitation edge in addition to the ground state.

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