Ab initio potential curves for the X2Σu+ and B2Σg+ states of Be2+: Existence of a double minimum

We report ab initio calculations of the X-2 Sigma(+)(u) and B-2 Sigma(+)(g) states of the Be-2(+) dimer. Full valence configuration interaction calculations were performed using the aug-cc-pVnZ basis sets and the results were extrapolated to the CBS limit. Core-core and core-valence effects are included at the CCSDT/MTsmall level of theory. Two local minima, separated by a large barrier, are found in the expected repulsive B-2 Sigma(+)(g) state. Spectroscopic constants have been calculated and good agreement is found with the recent measurements of Merritt et al. Bound vibrational levels, transition moments and lifetimes have also been calculated. (C) 2010 Elsevier B.V. All rights reserved.