THEORETICAL-STUDY OF THE RYDBERG EXCITED ELECTRONIC STATES OF AR2(+)

The first Rydberg states of the Ar2+ molecular ion dissociating into Ar+ (3p5,2P) + Ar*(3p(5)4s,3,1P) are calculated using multireference configuration interaction and effective core pseudopotentials. At long internuclear distance, their electronic structure is shown to be determined by resonance interaction and the magnitude of the Rydberg electron-transfer integral, inducing long-distance wells with D(e) in the range 0.6-0.8 eV around R(e) congruent-to 9.0a0. In the short distance range, the electronic structure can be understood as resulting from an ionic Ar++ core with an outer Rydberg electron, and bound or quasibound Rydberg states are obtained around R(e) approximately 4a0. The fluorescence spectra of those states are simulated and the possible intervention of the Ar2+ system in the third continuum spectrum is considered.