Ab initio potential curves for the X $^2\Sigma_u^+$, A $^2\Pi_u$ and B $^2\Sigma_g^+$ states of Ca$_{2}^+$

TL;DR

This paper presents detailed ab initio calculations of potential energy curves, spectroscopic constants, and polarizabilities for the calcium dimer cation's low-lying electronic states, providing valuable data for understanding its properties.

Contribution

It introduces comprehensive ab initio potential curves and spectroscopic data for Ca₂⁺ states, including a double well in the B state, using advanced computational methods.

Findings

Double well found in the B ²Σg⁺ state.

Spectroscopic constants and vibrational levels calculated.

Polarizabilities and van der Waals coefficients determined.

Abstract

We report \textit{ab initio} calculations of the X $^2 \Sigma_{u}^+$, A $^2\Pi_u$ and B $^2 \Sigma_{g}^+$ states of the Ca$_{2}^+$ dimer. All electron CAS+MRCI calculations are performed for the X $^2 \Sigma_{u}^+$ and B $^2 \Sigma_{g}^+$ states, while valence CAS+MRCI calculations using an effective core potential are used to describe the A $^2\Pi_u$ state. A double well is found in the B $^2 \Sigma_{g}^+$ state. Spectroscopic constants, vibrational levels, transition moments and radiative lifetimes are calculated for the most abundant isotope of calcium ($^{40}$Ca). The static dipole and quadrupole polarizabilities, and the leading order van der Waals coefficients are also calculated for all three states.