Nonadiabatic effects in the B, C and E, F states of HD
Abstract
This paper reports the results of a theoretical study of the nonadiabatic interactions among the B ^{1}Σ_{u}^{+}, C ^{1}Π _{u}, and E, F ^{1}Σ_{g}^{+} states of the HD molecule. The required electronic matrix elements were computed from configurationinteraction wavefunctions. The radial coupling between the B and E, F states, which involves the {∂}/{∂R} operator, was treated both by numerical differentiation procedures and also by transforming away the {∂}/{∂R} operator through use of the HellmannFeynman theorem. Good agreement between these two approaches was obtained. The nonadiabatic calculation yields C state Λdoubling values in good agreement with experiment. We also present relative and absolute rotational line strengths for transitions from the ground state ( V_{X} = 0) to this trio of interacting states. Nonadiabatic effects on these line strengths are large for all three band systems. Of particular interest are the E, F ← X bands, where the dipole transitions are allowed only because of these nonadiabatic couplings. These dipole transitions have been recently observed experimentally by Dabrowski and Herzberg [ Canad. J. Phys., 54, 525 (1976)].
 Publication:

Journal of Molecular Spectroscopy
 Pub Date:
 September 1977
 DOI:
 10.1016/00222852(77)900467
 Bibcode:
 1977JMoSp..67..336A