Influence of Vibration-Rotation Interaction on Line Intensities in Vibration-Rotation Bands of a Rotating Morse Oscillator.

Abstract

The effect of vibration-rotation interaction on line intensities in vibration-rotation bands of diatomic molecules is investigated for a diatomic molecule treated as a rotating Morse oscillator with fixed electronic angnlar momentum. The matriz element of the electric dipole moment is calculated for the transitionv,J, ', J', X, using Morse-Pekeris wave functions, where the electric dipole moment is written as a Taylor series expansion about the equilibrium internuclear separation. The matrix element of the nth-order term in the dipole-moment expansion can be simply derived from the matrix element of the zeroth-order term. The rnatdx elements of the first four terms are given explicitly. These results greatly extend those of the perturbed harmonic oscillator treatment of Herman and Wall is, since they apply to all V, V' to within the accuracy of the expansion of the rotational energy. The matrix elements obtained when J 0 and X H 0 generalize the results obtained by Heaps and Herzberg, since they include all the terms in the electric dipole-moment expansion.