Theoretical Study of The Low-Lying [sup 1]Σ[sup +] Electronic States Of The Alkaline Earth BeLi[sup +] Ion

Abstract

The adiabatic potential energy curves and the spectroscopic constants of the ground state and many excited states of 1Σ+ symmetry for the alkaline earth ion BeLi+ have been investigated. We have used an ab initio approach based on non‐empirical pseudopotentials for the Be2+ and Li+ cores, parametrized l‐dependent polarization potentials and full configuration interaction calculations. The ground state spectroscopic constants are in good agreement with the available theoretical results; whereas these spectroscopic properties for the excited states are presented for the first time. Moreover, numerous avoided crossings between electronic states of 1Σ+ symmety have been localised and analysed. They are related to the interaction between the electronic states and to the charge transfer process between the two ionic systems Be+Li and BeLi+. Furthermore, the permanent and transition dipole moments are determined for a wide interval of internuclear distances. The permanent dipole moments for the X(1)1Σ+ and 31Σ+ electronic states have shown a linear behavior, especially, at intermediate and large distances, while the transition dipole function between neighbor states have revealed many peaks located around the avoided crossing positions. This work extends our recent study on the alkaline earth BeLi2+ ion and represents the necessary initial step towards the charge transfer processes in collisions of ions with atoms.