Convergence properties of a pertubative treatment for Coriolis coupling in symmetric top molecules

Abstract

The applicability of perturbation theory to a vibration-rotation Hamiltonian for two Coriolis interacting (A-E) vibrational states of a symmetric top molecule is studied. The energy levels of the A state are expressed as power series on the Coriolis parameter, and the properties of convergence of the expansion are analyzed. The radii of convergence of these series are calculated both by locating the singularities of the energy as a function of the Coriolis constant, and also by using an expression based on the spectral properties of the perturbation operator. An application of this study to the ν2 band of SO3, which is weakly coupled with the ν4 band, is shown, and a critical discussion of the results is presented. © Published by Elsevier Inc.1991.