A selection rule in SiHn(n=1–4)+F reactions: An ab initio molecular orbital study

Abstract

Reactions of SiHn(n=1–4) with a fluorine atom were studied by using an ab initio molecular orbital method [fourth-order Mo/ller–Plesset (MP4/6-21G**//second-order Mo/ller–Plesset MP2/6-21G**)]. Structures of the transition states were determined. In the cases of SiH3+F and SiH+F, fluorine atom addition to a silicon atom was a favorable reaction at the singlet state and abstraction of a hydrogen by a fluorine atom was a favorable route at the triplet state. Abstraction of a hydrogen was also favorable at the doublet state in the case of SiH2+F. A selection rule of these reactions on the basis of the atomic spin density on each atom was proposed. The selection rule proposed was proved to also be applicable to the reaction CH3+F.