Geometrical configurations of H4+ and the Jahn–Teller effect

The present calculations have given 10 stable geometrical configurations with their electronic states for the H4+ ion using HF and QCISD with the 6-311G** basis set. We examined the Jahn–Teller distortions from the configurations H4+(D4h) and H4+(Td). The analysis of the relationships among these various geometrical configurations, based on the Jahn–Teller effect, vibronic interaction and the resolution of group representations, is in fair agreement with the calculated results. The orbitally degenerate electronic states Eg and Eu of the configuration H4+(D4h) are distorted into 2B1u (rectangle and rhomboid) of H4+(D2h), and the orbitally degenerate electronic states T2 and E of H4+(Td) are distorted into 2A1 of H4+(C3v), 2B1 and 2A1 of H4+ (planar and nonplanar C2v), and 2A′ of H4+ (planar or nonplanar Cs). The most stable electronic state of H4+ is 2A1 of the planar C2v configuration.