Site-specific ion desorption from condensed F3SiCD2CH2Si(CH3)3 induced by Si-2p core-level ionizations studied with photoelectron photoion coincidence (PEPICO) spectroscopy, Auger photoelectron coincidence spectroscopy (APECS) and Auger electron photoion coincidence (AEPICO) spectroscopy

Abstract Ion desorption from condensed F 3 SiCD 2 CH 2 Si(CH 3 ) 3 induced by Si-2p core-level ionizations of the F 3 Si and the Si(CH 3 ) 3 sites (Si[F] and Si[Me]) was investigated using photoelectron photoion coincidence (PEPICO) spectroscopy, Auger photoelectron coincidence spectroscopy (APECS) and Auger electron photoion coincidence (AEPICO) spectroscopy. A Si-2p-F + PEPICO peak appeared selectively in the Si[F]-2p region. Si-2p-H + PEPICO peaks were, on the other hand, observed in both the Si[Me]- and Si[F]-2p regions. The structure of the Si-L 23 VV-Si[F]-2p Auger photoelectron coincidence spectrum (APECS) was quite different from that of the Si-L 23 VV-Si[Me]-2p APECS. Ab initio molecular orbital calculations qualitatively reproduced the measured APECSs. The peak positions in the Si-L 23 VV-F + AEPICO spectrum were in good agreement with those in the Si-L 23 VV-Si[F]-2p APECS. The Si-L 23 VV-H + AEPICO spectrum, on the other hand, showed no characteristic peaks. Based on these results we have concluded that the site-specific F + desorption is stimulated by Si[F]-L 23 VV Auger processes, and that both the Si[Me]- and Si[F]-L 23 VV Auger decays are responsible for the non-site-specific H + desorption.