title: Energy level promotion in the correlation from the tunnelling-doubled harmonic oscillator to the bi-rotor: application to internal rotation in molecules.
abstract: A surprisingly rich variety of phenomena are revealed in the energy level correlation between the limits of a tunnelling doubled harmonic oscillator and a bi-rotor. Some levels are found to have their vibrational quantum number "promoted" upon removal of the barrier to rotation, other levels, which we dub "invariant", are found to be completely independent of the barrier, while yet other levels exhibit a smooth transition between these limits. The general nature of these features can be understood in terms of the different degeneracies of the limiting cases. The elucidation of these effects aids the understanding of the rotational-vibrational energy levels of molecules having two internal rotor moieties.
authors.affiliation: Department of Physics and Centre for Laser, Atomic, and Molecular Sciences, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, Canada E3B 5A3.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Ross
authors.forename: Koichi M T
authors.initials: KM
authors.lastname: Yamada