Ab initio potential curves for the X ${}^2{\Sigma }_u^{+}$, A ${}^2{\Pi }_u$ and B ${}^2{\Sigma }_g^{+}$ states of Ca${}_2^{+}$

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.

6 pages, 5 figures