The geometry and spectral properties of Ne+3, Ar+3, Kr+3, and Xe+3

Abstract

Ab initio polarization configuration interaction (POL‐CI) calculations show that Ne⁺₃ and Ar⁺₃ are both linear, in agreement with indirect experimental evidence on Ar⁺₃ and in contradiction to earlier approximate theoretical calculations on Ar⁺₃, which predicted an equilateral triangular geometry. The experimentally unknown Ne⁺₃ dissociation energy is predicted to be 0.15±0.01 eV. Simple diatomics‐in‐molecules (DIM) calculations were shown to be in very good agreement with the ab initio results. DIM calculations predict that Kr⁺₃ and Xe⁺₃ are also linear. All the rare‐gas–trimer ions possess at least one very strong absorption band in the visible, even stronger than the near ultraviolet absorption band of the rare‐gas–dimer ions.