Determinable parameters of the effective rotational Hamiltonians for excited vibrational states of semirigid symmetric top molecules of C4v, D4, D2h, andD2d symmetry

Abstract

A general method is described for obtaining the S functions which in the contact transformation of the vibration-rotation Hamiltonian of semirigid molecules with the fourfold symmetry axis eliminate the rotational and vibrational l-type operators and the Δk = ±4 centrifugal distortion operators from the λH1 terms of the expanded Hamiltonian. Explicit expressions are given for the vibration-rotation energy levels with independent effective spectroscopic parameters. Expressions are also given for the splittings of energy levels with essential resonances.