Spectroscopic constants for GaAs2-, GaAs2, Ga2As-, and Ga2As

Low-lying electronic states of Ga2As-, Ga2As, GaAs2-, and GaAs2 are investigated using complete active space multiconfiguration self-consistent field technique followed by multireference singles + doubles configuration interaction calculations that included 5.5 million configurations. Our computations reveal the existence of two excited states of the Ga2As- anion close to the neutral ground state of Ga2As, which also exhibits two nearly degenerate states of C-s and C-2 upsilon geometries. Assignments to the recently observed anion photodetachment and far-IR spectra are suggested.