Ab initio adiabatic and quasidiabatic potential energy surfaces of H+ + CO system: A study of the ground and the first three excited electronic states

Abstract

The global ground and first three excited electronic state adiabatic as well as the corresponding quasidiabatic potential energy surfaces is reported as a function of nuclear geometries in 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. Nonadiabatic couplings, arising out of relative motion of proton and the vibrational motion of CO, are also reported in terms of coupling potentials. The quasidiabatic potential energy surfaces and the coupling potentials have been obtained using the ab initio procedure [Simah et al., J. Chem. Phys. 111, 4523 (1999)] for the purpose of dynamics studies.

Rovibrational quenching of C2− anions in collisions with He, Ne, and Ar atoms

“…When vibrations are involved, the situation is more complicated as states can be coupled via the r vibrational coordinate. This is the case for the H + -CO and H + -CN systems which have been studied by Kumar et al [85][86][87]. For these systems the naked positive charge of the proton has a strong perturbing effect and can couple the molecule's electronic states.…”

“…are the electronic wave functions and the operator is the first (n = 1) or second (n = 2) derivative with respect to the nuclear coordinate Q (=r for diatomics) [85][86][87]. The coupling matrix was used to carry out H + -CO scattering calculations by constructing diabatic PESs for two electronic states allowing a computation of elastic, vibrationally inelastic, and charge transfer probabilities [88].…”

Rovibrational quenching of C$_2$-anions in collisions with He, Ne, and Ar atoms

“…For these systems the naked positive charge of the proton has a strong perturbing effect and can couple the molecule's electronic states. The strength of the coupling can be calculated as {ψ α i | ∂ n ∂Q n |ψ α j } where ψ α i/j are the electronic wavefunctions and the operator is the first (n = 1) or second (n = 2) derivative with respect to the nuclear coordinate Q (= r for diatomics) [85][86][87]. The coupling matrix was used to carry out H + -CO scattering calculations by constructing diabatic PESs for two electronic states allowing a computation of elastic, vibrationally inelastic and charge transfer probabilities [88].…”