Comparison of theory and experiment for excited singlet states of the H2 molecule

This paper presents a survey of published and unpublished ab initio calculations of the vibrational structures of the ten lowest electronic singlet states of the hydrogen molecule up to the H(n = 1) + H(n = 2) dissociation limit. The data are based on adiabatic potential functions (clamped-nuclei electronic energies and nuclear-mass-dependent diagonal corrections). Nonadiabatic coupling has been treated ab initio within the five states. of ¹Λ symmetry (X,EF, GK, HH?) and ¹Σ I.¹Π_g. The accuracies of the theoretical energies are determined by comparisons with experimental data for H₂, HD, and D₂. The level shifts and predissociation probabilities of the excited ¹Σ states, generated by nonadiabatic coupling with the discrete and continuous vibrational structure of the ground state, and radiative properties have also been calculated.