Low-lying electronic states of the rare gas oxides

Abstract

Ab initio configuration interaction calculations have been carried out on the electronic states of RgO (Rg=Ne, Ar, Kr, and Xe) arising from the Rg(¹S)+O(³P, ¹D, and ¹S) separated atom limits. All potential curves, with the exception of the 1 ¹Σ⁺ curve in KrO and XeO, are found to be repulsive (with at most van der Waals minima). The binding in the 1 ¹Σ⁺ state is due in part to the incorporation of Rg⁺+O⁻ character and increase in the series: NeO (unbound) to ArO (essentially flat) to KrO (D_e=0.25 eV) to XeO (D_e=0.70 eV). The admixture of ionic character into the 1 ¹Σ⁺ state also strongly enhances the 2 ¹Σ⁺–1 ¹Σ⁺ transition, increasing the collision induced emission rate from O(¹S) and decreasing the lifetime of the 2 ¹Σ⁺ state. The calculations also provide information on the quenching of O(¹D) by the rare gases.