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

摘要

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 ~1σ 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 ~+).