Core-level anionic photofragmentation of gaseous CCl4 and solid-state analogs

Abstract

The dissociation dynamics of anionic and excited neutral fragments of gaseous CCl4 and CCl4 adsorbed on Si(100) similar to 90 K following Cl 2p core-level excitations were investigated on combining measurements of photon-induced anionic dissociation, x-ray absorption, and uv-visible dispersed fluorescence. The transitions of core electrons to high Rydberg states or doubly excited states near Cl 2p ionization thresholds of gaseous CCl4 remarkably enhance the production of excited neutral fragments (C* and CCl*); this enhancement is attributed to the contribution from the shake-modified resonant Auger decay and/or postcollision interaction (PCI). The Cl-anion is significantly reinforced in the vicinity of the Cl 2p(1/2,3/2) ionization threshold of gaseous CCl4, originating from PCI-mediated photoelectron recapture. The Cl 2p -> 7a(1)* excitation for CCl4/Si(100) at similar to 90 K enhances the Cl- desorption yield at a submonolayer level. This resonant enhancement of Cl-yield at the 7a(1)* resonance in the Cl 2p edge at a submonolayer level occurs through the formation of high-lying molecular-ion states of CCl4 adsorbed on a Si surface.