FTIR SPECTROSCOPY AND FIR LASER ASSIGNMENTS FOR O-18 METHANOL

Author Institution: CEMAID and Department of Physics, University of New Brunswick; Dept. of Physics, Memorial University of Newfoundland; CEMAID and Dept. of Chemistry, University of B.C.; Department of Chemistry and Biochemistry, Southern Illinois University; Herzberg Institute of Astrophysics, National Research Council of CanadaHigh-resolution FTIR spectra of O-18 methanol have been obtained in the region $900-1620 cm^{-1}$. This covers the $C-O$ stretching, $CH_{3}$-rocking, $CH_{3}$-deformation and OH-bending bands. Analysis of these bands is underway, with particular interest in the values of $V_{3}$, the barrier height to internal rotation, in the excited vibrational states. The weak in-plane $CH_{3}$-rocking band lying just above the strong $C-O$ stretch has been analyzed extensively, and is found to have a barrier of $477.8(2.1) cm^{-1}$, representing a 27\% increase over the ground state value. Several far-infrared laser lines have been assigned from our spectroscopic results, with parent IR pump transitions originating not only from the usual $C-O$ stretch band but also the $CH_{3}$-rocking band. With our complementary study of the ground-state FIR torsion-rotation spectrum, most of the FIR laser assignments have been confirmed with closed combination loops. The general features of interest in the various vibrational bands will be discussed, along with our current information on the B-values and barrier heights for the excited states."