QUANTUM CANONICAL TRANSFORMATION OF THE ROTATIONAL VIBRATIONAL HAMILTONIAN TO REMOVE A CORIOLIS TERM

A quantum mechanical rotational-vibrational Hamiltonian with one Coriolis term which couples vibration and rotation is transformed to eliminate the Coriolis term. This is achieved by employing a Bogoliubov-Tyablikov transformation. A closed-form energy level expression is obtained for the vibrational-rotational energy levels of a rigid symmetric top coupled to harmonic oscillators. For an asymmetric rotor the transformation introduces small off-diagonal matrix elements which couple vibrational states. Nearly degenerate vibrational states would be strongly coupled by the original Coriolis term, but the small off-diagonal matrix elements of the transformed Hamiltonian may be treated perturbatively to obtain an effective rotational Hamiltonian for each vibrational state. The new theoretical method is compared with variational calculations.