Ab initio potentials for states of XeI, XeI− and XeI+

Results from high-level quantum chemical computations (coupled clusters [CCSD(T)] and multireference average coupled-pair functional [MR-ACPF], using relativistic effective core potential [ECP] basis sets) are presented for XeI, XeI− and XeI+. Comparison is made with published determinations of bond length, dissociation energy and vibrational parameters from atomic scattering, fluorescence, zero electron kinetic energy photoelectron spectroscopy experiments, and previous calculation. For the neutral molecule, MR-ACPF, including spin-orbit coupling, provides results for all six valence states. Overall, good agreement between calculated and experimental results is observed. Further, predictions for the harmonic vibrational frequency and anharmonicity of XeI+, a species which has not yet been observed in experiment, are given for the first time.