Regresar

MO ab initio MCSCF calculation of the charge topology in the H abstraction from CH<inf>4</inf> by MgO and LiO molecules

Abstract:

MCSCF-CAS and SCF ab initio calculations were carried out for the abstraction of H from CH4 by MgO and LiO molecules. Effects of the electron correlation on internuclear distances, reaction energies, and Laplacian of the charge density ∇2ρ(r) of the O valence shell were studied. An excellent correlation between the values of-∇2ρ(r) at an external saddle point of this shell and the activation barrier for the H abstraction from CH4 already reported was obtained. In this way, the use of -∇2ρ(r) has been extended to include the pbkp_rediction of the chemical reactivity of a reaction involving a homolytic break of a pair of bonding electrons. The changes in the charge bkp_redistribution in going from the reactants to the transition state and to the products was also determined in terms of variations of -∇2ρ(r) at the critical points of the valence shells. © 1993 American Chemical Society.