Strong Electronic Selectivity in the Shallow Core Excitation of the CH2Cl2 Molecule

The photoexcitation and multiphotoionization of the dichloromethane molecule have been studied for photons with energies from 100 eV to the Cl 2p edge, using the time-of-flight multicoincidence technique and synchrotron radiation. The electronic de-excitation gives rise to one to three electrons and an ionic molecule that decays onto smaller moieties through several fragmentation channels. To discern the channels, sets of fragments have been dispersed in time, measured in coincidence, and recorded as a function of incident photon energy. The chlorine ion, Cl(+), has the highest intensity around and above the Cl 2p edge, while the CHnCl(+) ion, corresponding to the loss of one neutral chlorine atom, dominates the mass spectra in the valence region. In addition, strong electronic selectivity has been observed for the core-excited molecule.