Ab initio study of the alkali-dimer cation Li2+

The potential energy curves and the spectroscopic constants of the electronic states of (2)Sigma(+)(g,u), (2)Pi(g,u) symmetries of Li-2(+) ionic system dissociating into Li (2s, 2p, 3s, 3p, 3d, 4s and 4p) + Li+, have been calculated using an ab initio approach. A non-empirical pseudo potential for the Li (1s(2)) core has been involved and a core-core and core-valence correlation have been added. A good agreement has been obtained for the ground and the first excited states with the available theoretical and experimental works. However, a clear disagreement between this study and the model potential work of [S. Magnier, S. Rousseau, A.R. Allouche, G. Hadinger, M. Aubert-Frecon, Chem. Phys. 246 (1999) 57] has been observed for several excited states. They found that the 6-7 (2)Sigma(+)(g), 3-4, 6 (2)Sigma(+)(u), 2 (2)Pi(u) and 1 (2)Delta(u) states are repulsive, although they are attractive with potential well depths of 10, 100 and 1000 cm(-1) in our study. (c) 2006 Elsevier B.V. All rights reserved.