Non-adiabatic calculations for H₂⁺, HD⁺ and D₂⁺

Abstract

Non-adiabatic calculations are reported for the two lowest non-rotational energy levels of H₂ ⁺, HD⁺ and D₂ ⁺. They are lower in energy than previously published non-adiabatic calculations and the dissociation energies are 21 379·28, 21 515·99 and 21 711·51 cm^-1 for H₂ ⁺, HD⁺ and D₂ ⁺, respectively. Certain approximate ratios for the non-adiabatic corrections are discussed and shown to be in reasonable agreement with the exact ratios. It is suggested that the Unsöld average-energy denominator for H₂ ⁺ should lie between 2·6 × 10⁵ and 3·6 × 10⁵ cm^-1.