Ab initio Potential Energy Surface for Ne–Li2 in Its Ground Electronic State

Abstract

We present the results of a detailed study of the first accurate 3D ground state interaction potential energy surface (PES) of the Ne–Li2 system by quantum calculations using the coupled-cluster singles and doubles excitation approach with perturbative treatment of triple excitations [CCSD(T)]. The calculations were carried out for the frozen molecular equilibrium geometries and for an extensive range of the remaining two Jacobi coordinates, R and θ, for which a total of about 1976 points is generated for the surface. Mixed basis sets, aug-cc-pVTZ for the Ne atom and cc-pCVTZ for the Li atom, with an additional (3s3p2d2f1g) set of midbond functions are used. The ab initio points on the PES are fitted to a 96-parameter algebraic form with an average absolute error of 0.00000255% and a maximum error less than 0.00888%. The experimental results are compared with our ab initio potential surface calculations. Our PES gives more accurate results along with the experimental data.