Further contributions to the energy levels of a perturbed anharmonic oscillator: Application to adiabatic corrections

Abstract

The investigation of further contributions to the energy levels of a perturbed anharmonic oscillator is continued. It is shown that, by using a Taylor series for several variables, the contributions to the energy levels due to an additional perturbing interaction can be directly derived from the Yun Dunham-type coefficients by means of analytic relations involving products of differential operators. Consequently, the analytic expressions for the whole set of these contributions are generated from the Yu0 coefficients alone and are easily calculated by using a computer algebraic manipulation language. As an illustrative application, the case of the adiabatic corrections for nuclear motion to the potential energy curves of diatomic molecules in 1Σ+ states, such as lithium hydrides and hydrogen chlorides, is considered.