CORIOLIS RESONANCE AND LOCALIZED PERTURBATION'S IN $\nu_{3}+\nu_{4}$ OF $CH_{3}F^{*}$

Abstract

“A perpendicular baud of $CH_{3}F$ at $4058\;cm^{-1}$ obtained under high resolution ($\approx .04 cm^{-1}$) displays numerous resolved P, Q and R branch lines. Over 500 transitions, have been identified in a $200\;cm^{-1}$ region. A Coriolis resonance which lifts, the degeneracy of the $K’ =l= \pm 1$ levels has been observed and the Coriolis constant q has been obtained from an analysis of the individual $^{R} Q_{o}(J), ^{R} R_{o}(J)$ and $^{R} P_{0}(J)$ transitions. In addition there is a general perturbation of levels with high J and low K us well as several relatively strong localized perturbations, the strongest of which occurs for the $K’ = 2, l = \pm 1$ levels. The positions of the individual transitions in the $^{R} Q_{1} (J)$ and $^{P}Q_{\delta} (j)$ series clearly display the form and effect of this perturbation which is ascribed to an accidental resonance with a nearby vibration-rotation band.”