title: Dissociation of chloromethanes upon resonant σ* excitation studied by x-ray scattering.
abstract: The dissociation process following the Cl K-shell excitation to σ* resonances is studied by high resolution spectroscopy of resonant elastic and inelastic x-ray scattering on CH3Cl, CH2Cl2, CHCl3, and CCl4 molecules. Calculations employing the transition potential and Delta-Kohn-Sham DFT approach are in good agreement with the measured total fluorescence yield and show the presence of a second quasidegenerate group of states with σ* character above the lowest σ* unoccupied molecular orbital for molecules with more than one Cl atom. A bandwidth narrowing and a nonlinear dispersion behavior is extracted from the Kα spectral maps for both σ* resonances. The fitted data indicate that the widths of the Franck-Condon distributions for the first and second σ* resonances are comparable for all the molecules under study. In addition, an asymmetric broadening of the emission peaks is observed for resonant elastic x-ray scattering with zero detuning on both σ* resonances. This is attributed to the fast dissociation, transferring about 0.15 of the scattering probability into higher vibrational modes.
authors.affiliation: Jožef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia.
authors.forename: R
authors.initials: R
authors.lastname: Bohinc
authors.forename: M
authors.initials: M
authors.lastname: Žitnik
authors.forename: K
authors.initials: K
authors.lastname: Bučar
authors.forename: M
authors.initials: M
authors.lastname: Kavčič
authors.forename: L
authors.initials: L
authors.lastname: Journel
authors.forename: R
authors.initials: R
authors.lastname: Guillemin
authors.forename: T
authors.initials: T
authors.lastname: Marchenko
authors.forename: M
authors.initials: M
authors.lastname: Simon
authors.forename: W
authors.initials: W
authors.lastname: Cao