Metastable homonuclear diatomic trications [formula omitted] for elements X from the first three rows of the periodic table

Abstract

Motivated by a systematic stability scan of the homonuclear diatomic systems with elements from hydrogen to argon, we investigated in detail the ensuing five candidates for metastable trications, viz., O23+, P23+, S23+, Cl23+, and Ar23+ by multireference configuration interaction computations. Each of these tricationic systems exhibits a barrier in its ground state potential energy curve leading to quasi-bound nuclear motion. The resulting lifetimes vary drastically; while S23+ and Cl23+ in their lowest vibrational states can be regarded as practically stable, the predicted lifetimes of O23+ and Ar23+ are too short to allow a mass spectroscopic detection of these systems by current experimental capabilities. In the case of Ar23+, the theoretically predicted existence of quasibound vibrational levels also depends on whether or not relativistic corrections are taken into account.