Si:2p site-specific excitation and fragmentation of bridged trihalosilyl–trimethylsilyl molecules: role of the bridge and final-state effect

Abstract

To elucidate site-specific phenomena, we experimentally and computationally studied the spectroscopy and dynamics caused by Si:2p core-level photoexcitation of bridged trihalosilyl–trimethylsilyl molecules. We used the photoionization efficiency curve and the photoelectron photoion coincidence method to study the site-specific phenomena in the Si:2p photoexcitation of F 3SiCH 2CH 2CH 2Si(CH 3) 3, F 3SiCHCHSi(CH 3) 3 and Cl 3SiCCSi(CH 3) 3 in the vapor phase. The site-specific excitation was revealed in the photoionization efficiency curves of all the molecules. The site-specific fragmentation is likely to be more evident when the distance between the two Si sites is large. For the site-specific fragmentation to be caused by the Si:2p photoexcitation, there should not be a CC bond between the atomic site of interest and any other near atomic site around which bond dissociation is undesirable. Not only initial-state effect but also final-state effect is likely to contribute to the occurrence of the different chemical shifts between the two Si sites of the bridged trihalosilyl–trimethylsilyl molecules.