Eur. Phys. J. D 60, 263-267 (2010)
https://doi.org/10.1140/epjd/e2010-00203-8

Spin-orbit coupling in the ground and low-lying excited states of HF⁺ and HF^-

Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, 610065, P.R. China

Corresponding author: ^a gaotao@scu.edu.cn

Received: 12 January 2010
Revised: 11 April 2010
Published online: 27 July 2010

Abstract

Electronic structure and spectroscopic properties B_e, ω_e, ω_ex_e, α_e, T_e of ground state and the low-lying excited states of HF⁺ and HF^- molecular ions were investigated within scalar relativistic multireference configuration interaction with single and double excitations framework using the GAMESS-US program package. All potential energy curves (PECs) were calculated using the relativistic complete active space self-consistent field/spin-orbit multi-configuration quasi-degenerate perturbation theory (CASSCF/SO-MCQDPT). The curves are all fitted to the analytical potential energy function (APEF), from which accurate spectroscopic constants are derived. The spin-orbit splitting was also been studied, the split value of X state of HF⁺ is determined to be 288.38 cm^-1. The calculated properties are in good agreement with the available experimental value. Spectroscopic constants of the ground states of HF^- that have never been observed in experiment are obtained. These curves provide an interpretation of the known experimental observations on this system and suggest a number of further experiments which possible provide a critical test of this data.