Site-specific electron-relaxation caused by Si:2p core-level photoionization: Comparison between F₃SiCH₂CH₂Si(CH₃)₃ and Cl₃SiCH₂CH₂Si(CH₃)₃ vapors by means of photoelectron auger electron coincidence spectroscopy

Site-specific electron relaxations caused by Si:2p core-level photoionizations in F₃SiCH₂CH₂Si(CH₃)₃ and Cl₃SiCH₂CH₂Si(CH₃)₃ vapors have been studied by means of the photoelectron Auger electron coincidence spectroscopy. F₃SiCH₂CH₂Si(CH₃)₃ shows almost 100% site-specificity in fragmentation caused by the Si:2p ionization. However, substitution of Cl for F of F₃SiCH₂CH₂Si(CH₃)₃ considerably reduces the site-specificity at the Si atom bonded to three halogen atoms, with the site-specificity at the Si site bonded to three methyl groups remaining largely unchanged. The site-specificity reduction in Cl₃SiCH₂CH₂Si(CH₃)₃ is considered to take place during the transient period between Si: L₂₃VV Auger electron emission and the subsequent fragmentation. The reason for the reduction can be explained in terms of some differences between these two molecules in the L₂₃VV Auger decay at the Si site bonded to the three halogen atoms.