The stereodynamics of the O(1D)+HD reaction on the ground 1 1A′ and excited 1 1A″ potential energy surfaces

Abstract

The stereodynamics of the O(1D)+HD(v=0,j=0) reaction has been studied theoretically on the Dobbyn–Knowles (DK) ab initio potential energy surfaces (PES). Quasiclassical trajectory (QCT) calculations have been carried out on the 1 1A′ ground state PES and both QCT and quantum mechanical (QM) calculations have been performed on the 1 1A″ excited state PES. The product rotational angular momentum (j′) polarization in the (k,k′) scattering frame (i.e., the k–k′–j′ vector correlation) has been determined for selected rovibrational states of the OH(v′,j′)+D and OD(v′,j′)+H product channels at the collision energy of 0.196 eV. The agreement between the QM and QCT results is very good and indicates that the “abstraction” reaction occurring on the excited 1 1A″ PES yields OH and OD products strongly polarized, in strong contract with the “insertion” reaction occurring on the ground 1 1A′ PES, which leads to an essentially isotropic distribution of the product rotational angular momentum. The differentiated stereodynamics on the 1 1A′ and 1 1A″ surfaces constitutes a reference for experimental research with the aim of assessing the contribution of the excited 1 1A″ surface to the overall reactivity of this system.