On the Assignment of Optically Pumped Far-Infrared Laser Emission from CH(3)OH.

Progress in the analysis of the infrared spectrum of CH(3)OH in the 930-1450 cm(-1) region has led to assignments, confirmations, or new insights for a number of far-infrared laser (FIRL) transition systems optically pumped by CO(2) lasers. Many of the systems involve FIRL transitions among the CO-stretching, CH(3)-rocking, OH-bending, and CH(3)-deformation vibrational modes, giving useful information on the torsion-rotation structure of the methanol vibrational energy manifold. Some anomalies and mysteries concerning the identity of the lasing levels have been resolved, but several new ones have arisen. Altogether, 45 CH(3)OH IR-pump/FIR-laser systems are examined in light of the new spectroscopic information; about half of the system assignments are new and half have been previously reported in the literature and are here confirmed, extended, or revised. Copyright 1999 Academic Press.