Torsional energies, matrix elements and relative intensities of far-infrared absorption transitions in CH 2DOH

Abstract

In this paper, the relative intensities of far infrared transitions in the torsional ground state of asymmetrically deuterated methanol CH 2DOH are reported, using an internal axis method (IAM) theory. Relative intensities are presented for all possible strong b- and c-type Far Infrared (FIR) transitions upto K = 15 in the torsional vibrational ground state. Matrix elements for Δ K = ± 1 transitions have been calculated upto the fourth excited torsional state. The calculations will be valuable in the assignments of far-infrared spectra and optically pumped far-infrared laser lines. The energy levels calculated will provide excellent data base for astrophysical detection of asymmetrically substituted methanol, which is of significant importance for the determination of parameters like the D H ratio in the universe.