Ab initio potential surface for H4+

A portion of the potential surface of H4+ was calculated with several wavefunctions based on valence bond configuration interaction. Polarization and ionized structures were considered. The calculated potential surface shows a long range attraction between H2 and H2+ which becomes strong at short distances. Calculations were made on a potential hypersurface containing a favorable reaction coordinate for the reaction H2+ H2+→ H3++H. Simple wavefunctions without polarization show no long range attraction between H3+ and H; when polarization is included a long range attraction is found. Calculations with ionized structures and polarization suggest that H4+ is stable with a binding energy Do=0.85 kcal/mole. Failure to detect H4+ is attributed to the absence of a mechanism to produce this ion under experimental conditions.