GIANT K-DOUBLING IN THE INFRARED-SPECTRUM OF CH3OH - A SENSITIVE PROBE FOR CH3-ROCK CO-STRETCH/OH-BEND VIBRATIONAL COUPLING/

The asymmetry splittings of K-doublet levels in excited vibrational st ate of methyl alcohol are found to be sensitive indicators of intermod e interactions. Fourier transform spectra reveal giant K doubling of t he (n tau K)(V) = (122)(r) CH3-rocking levels due to a near resonance with the CO stretch. Several spectral anomalies are thereby explained, and a significant far-infrared laser transition system is reassigned. The K-doublet splittings will provide a useful tool for the study of torsion-mediated mode coupling and intramolecular energy transfer chan nels in methanol.