title: Double imaging photoelectron photoion coincidence sheds new light on the dissociation of energy-selected CH3Cl(+) ions.
abstract: The vacuum ultraviolet (VUV) photoionization and dissociative photoionization of CH3Cl in the energy range of 11-17 eV have been investigated in detail by combining synchrotron radiation and double imaging photoelectron photoion coincidences (i(2)PEPICO). Three low-lying electronic states of the CH3Cl(+) molecular ion, X(2)E, A(2)A1 and B(2)E, were prepared and analyzed. The appearance energies of the energetically accessible fragment ions, CH2Cl(+), CHCl(+), CH3(+) and CH2(+), have been obtained from their respective mass-selected threshold photoelectron spectra (TPES) or photoionization efficiency (PIE) curves. The dissociation mechanisms of energy-selected CH3Cl(+) ions, prepared in the A(2)A1 and the B(2)E electronic states, as well as outside the Franck-Condon region, have been revealed to be state-specific via ion/electron kinetic energy correlation diagrams. In particular, the umbrella mode vibrational progression of the CH3(+) fragment ion in the direct dissociation of the A(2)A1 electronic state was identified and assigned indicating that this state correlates to the CH3(+)(1(1)A1') + Cl((2)P1/2) dissociation limit, in agreement with the theoretical calculations performed in this work.
authors.affiliation: Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, 230031 Anhui, China. tangxf@aiofm.ac.in.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Tang
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Lin
authors.forename: Weijun
authors.initials: W
authors.lastname: Zhang
authors.forename: Gustavo A
authors.initials: GA
authors.lastname: Garcia
authors.forename: Laurent
authors.initials: L
authors.lastname: Nahon