Modified Dunham potential for rovibrational diatomic systems

Abstract

A modified Dunham potential with parameters depending on the rotational quantum number is employed to describe the rovibrational states of diatomic molecules. This approach, applied to H81Br, 115InD, 7LiH, and 40Ar2, gives satisfactory reproduction of the observed transitions using fewer Dunham parameters than in the standard method. The results obtained indicate the possibility of introducing the local internal potentials, which, in contradiction to the global ones usually used, depend on the rotational states of a rotating–vibrating molecule. Such a J dependence may be a result of rovibronic interactions, in particular, Coriolis-type nonadiabatic interactions coupling other electronic states through the rotational angular momentum.