Electronic relaxation and ion desorption processes of solid Si(CH3)2Cl2 following Si 2p core-level excitation

Abstract

High-resolution Si L23-edge x-ray absorption near-edge structure (XANES) total electron yield (TEY) spectrum and photon stimulated ion desorption (PSID) spectra of condensed Si(CH3)2Cl2 have been measured in the energy range of 102–115 eV using synchrotron radiation. Excitation from Si 2p to a Si–C antibonding orbital enhances the CH3+ formation, while excitation to the Si–Cl antibonding orbital gives rise to a pronounced Cl+ production. This indicates that the character of the bound terminating orbital has a significant influence on the fragmentation processes. The selective enhancement of H+ yield at a peak of ∼106.0 eV is interpreted in terms of the excited electron in the bound orbital with strong C–H antibonding character. Applying resonant photoemission spectroscopy, the spectator Auger process was found to be the dominant decay channel for the resonantly excited Si(2p) core hole of condensed Si(CH3)2Cl2. The close resemblance of the TEY and PSID spectra of solid Si(CH3)2Cl2 was attributable to spectator Auger decay of core excited states and subsequent Coulomb repulsion of multivalence hole final states as proposed by the Knotek and Fiebelman mechanism.