The low-lying electronic states of ArXe+ and their potential energy functions

Photoionization and pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectra of ArXe have been recorded between 96 400 and 108 200 cm(-1) following resonance-enhanced two-photon excitation via selected vibrational levels of the C 1 and D 0+ Rydberg states. The PFI-ZEKE photoelectron spectra consist of three vibrational progressions corresponding to the X 1/2<--X 0+, A1 3/2<--X 0+, and A2 1/2<--X 0+ transitions. From these progressions, adiabatic ionization energies, equilibrium internuclear distances, and vibrational constants have been derived for the lowest three electronic states of ArXe+. The photoionization spectra reveal long progressions of autoionizing Rydberg states converging to the lowest vibrational levels of the A1 3/2 state. A potential model has been developed that enables a global description of the low-lying electronic states of the heteronuclear rare gas dimer ions. The model explicitly treats the effects of the spin-orbit, charge-exchange, and long-range interactions. This model was used to obtain potential energy functions for all six low-lying electronic states of ArXe+ from the experimental positions of the vibrational levels of the X 1/2, A1 3/2, and A2 1/2 states relative to the ground neutral state and existing spectroscopic data on the B 1/2, C1 3/2, and C2 1/2 states.