HIGH-RESOLUTION FOURIER-TRANSFORM SPECTROSCOPY OF THE OVERTONE C-O STRETCH BAND OF METHANOL

In this work, assignments and analysis have been performed on the high resolution Fourier transform infra-red (IR) spectrum corresponding to the weak overtone C-O stretch band of methanol. The spectrum has the typical appearance of a Delta K = 0 spectrum of a near symmetric top m olecule and shows very complicated fine structure due the torsion-rota tion-vibration interaction in the molecule. It has been possible to id entify 15 different R- and P-sub-branch combinations spanning a K valu e of 6 in the torsional ground state. The assignments have been confir med from combination relations using R- and P- branch transitions havi ng the same upper level and accurately measured microwave and millimet rewave transitions in the ground vibrational state. Using the assigned transitions a set of molecular parameters has been obtained for the s econd excited C-O stretch state of methanol. (C) 1998 Elsevier Science B.V. All rights reserved.