Improved adiabatic corrections for the B 1Σ+u, C 1Πu, and D 1Πu states of the hydrogen molecule and vibrational structures for H2, HD, and D2

Publisher Website
Google Scholar
Abstract
The adiabatic energy corrections of the (2pσ) B 1Σ+u, (2pπ) C 1Πu, and (3pπ) D 1Πu states of H2 are calculated with higher accuracy than accomplished previously for a wide range of internuclear distances. The vibrational structures of these states are calculated for H2, HD, and D2 in the adiabatic approximation. Comparison with experimental term values of H2 and D2 permits one to separate the nonadiabatic energy shifts from the electronic contributions to the remaining energy discrepancies between ab initio theory and experiment. The electronic ab initio errors at and around the equilibrium internuclear distances of the respective states are thus found to be +0.8±0.2 cm−1 in the B state, +0.7±0.2 cm−1 in the C state, and +6.0±0.2 cm−1 in the D state. The adiabatic vibrational structures are also compared with the multichannel quantum defect treatment of nuclear motion in these states by Atabek and Jungen. The present calculation confirms the magnitudes of the so‐called specific mass or mass polarization corrections predicted by these authors.