Reaction of Mg(3s3p1P1) with a variety of alkyl C–H bonds: Identical initial MgH(X 2Σ+, v=0) rotational quantum state distributions

Abstract

The initial distributions of rotational quantum states of MgH(X 2Σ+, v=0) produced in the reaction of electronically excited Mg(3s3p1P1) with a variety of hydrocarbons containing alkyl C–H bonds have been found to be identical within experimental error. The distribution is peaked at fairly low values of rotational angular momentum (N≂10). This is in stark contrast to the reaction of Mg(1P1) with H2, where very high rotational excitation is observed and has been ascribed to side-on attack of the H–H bond. It is proposed that Mg(1P1) attacks alkyl C–H bonds directly in a relatively narrow cone of angles around the C–H bond axis and that the strength or location of a particular C–H bond has little effect on the dynamical process. Possible reasons for the differences in H2 and hydrocarbon as reactants are discussed, and the hydrocarbon results are compared to those reported by Luntz and co-workers on the reactions of O(3P) and O(1D2) with alkyl C–H bonds.