Theoretical study of the electronic structure of LiX and NaX (X = Rb, Cs) molecules

Adiabatic potential energy, spectroscopic constants, dipole moments, and vibrational levels have been computed for the lowest electronic states of alkali dimers LiX and NaX (X = Rb, Cs). Calculations have been carried with the use of an ab initio approach with core-potential potentials and full-valence configuration. Thus, these systems are treated as two-electron systems. A good agreement is obtained for some lowest states of the molecules studied with available theoretical works. The existence of numerous avoided crossings between electronic states for 1S symmetries is related to the charge-transfer process in each molecule between its two ionic systems (Li+X-, Li-X+) and (Na+X-, Na-X+). (c) 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011