Ab initio ground and the first excited adiabatic and quasidiabatic potential energy surfaces of H + + CO system

Abstract

Ab initio global adiabatic as well as quasidiabatic potential energy surfaces for the ground and the first excited electronic states of the H + + CO system have been computed as a function of the Jacobi coordinates ( R, r, γ) using Dunning’s cc-pVTZ basis set at the internally contracted multi-reference (single and double) configuration interaction level of accuracy. In addition, nonadiabatic coupling matrix elements arising from radial motion, mixing angle and coupling potential have been computed using the ab initio procedure [Simah et al. (1999) [66]] for the purpose of dynamics study. The geometrical properties corresponding to the minimum energy of the bound HCO + and HOC + isomers have been obtained and compared with those predicted by previous theoretical and experimental results. The HCO + has been found to be more stable than the HOC +. The minimum energy pathway in the ground electronic state for the isomerization process, HCO + ⇌ HOC + has also been obtained as a function of γ.