title: Exploring 1,2-hydrogen shift in silicon nanoparticles: reaction kinetics from quantum chemical calculations and derivation of transition state group additivity database.
abstract: Accurate rate coefficients for 35 1,2-hydrogen shift reactions for hydrides containing up to 10 silicon atoms have been calculated using G3//B3LYP. The overall reactions exhibit two distinct barriers. Overcoming the first barrier results in the formation of a hydrogen-bridged intermediate species from a substituted silylene and is characterized by a low activation energy. Passing over the second barrier converts this stable intermediate into the double-bonded silene. Values for the single event Arrhenius pre-exponential factor, A, and the activation energy, E(a), were calculated from the G3//B3LYP rate coefficients, and a group additivity scheme was developed to predict A and E(a). The values predicted by group additivity are more accurate than structure/reactivity relationships currently used in the literature, which rely on a representative A value and the Evans-Polanyi correlation to predict E(a). The structural factors that have the most pronounced effect on A and E(a) were considered, and the presence of rings was shown to influence these values strongly.
authors.affiliation: Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Adamczyk
authors.forename: Marie-Francoise
authors.initials: MF
authors.lastname: Reyniers
authors.forename: Guy B
authors.initials: GB
authors.lastname: Marin
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Broadbelt