Extended measurements of the ν2 band of CD3 and the determination of the vibrational potential function for methyl

Abstract

Measurements in the ν2 (umbrella) vibrational spectrum of CD3 are reported. The data include transitions up to and including the v2=4–3 bands and cover a wider range of rotational excitation than has been previously reported [Frye, Sears, and Leitner, J. Chem. Phys. 88, 5300 (1988)]. The spectroscopic data have been combined with all previously published data pertaining to the methyl radical and an estimate of the vibrational potential function for the species has been made. From this, we predict the positions of so far unobserved vibrational bands for all the various symmetric isotopic modifications and also extract an equilibrium structure. Preliminary results on the population distribution of v2 levels produced on the photofragmentation of acetone-d6 at 193 nm are reported and it is suggested that the methyl v3=1 and v3=0 levels may be produced in this reaction with a population inversion.