Diode-laser measurements of intensities and halfwidths in the ν6 band of 12CH 3D

Abstract

Absolute line intensities have been determined at room temperature for a total of 22 transitions belonging to r P and p P subbands in the ν 6( E) perpendicular band of 12CH 3D between 1062 and 1114 cm −1 under Doppler-limited resolution using a tunable diode-laser spectrometer system. Although the line intensities were determined with good precision (≈3%), the squared vibrational transition dipole matrix element derived from each line intensity showed large variations (≈500%) indicating intensity perturbations, possibly caused by Coriolis interactions between the ν 3, ν 5, and ν 6 fundamentals. The “Herman-Wallis” F-factor coefficients derived from the r P and p P subband transitions were significantly different from each other, but compared well with those reported in a recent study by M. Delaveau (Ph.D. thesis, Université de Paris-Sud, Orsay, 1985) using a Fourier transform spectrometer. Room temperature air- and nitrogen-broadened halfwidths have also been determined for 24 lines. The average of the ratios of nitrogen- to air-broadened halfwidths was 1.01 with a standard deviation of 0.01, giving almost equal broadening efficiencies for nitrogen and air. Room temperature self-broadened halfwidths were derived for two transitions with a mean value of 0.081 ± 0.001 cm −1 atm −1 at 296 K.