Knowledge Bank

Absolute line intensities were measured at room temperature for 21 transitions in the $\nu 6$ (E) perpendicular band of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}CH3D$ in the $1090-1140cm-1$ region using a tunable diode laser spectrometer. Although the line intensities were determined with high precision (= 3%), the square of the vibrational transition dipole moment matrix element derived from each line intensity varied by several percent (= 20%) indicating intensity perturbations, possibly caused by Coriolis interactions with the nearby $\nu 3$ parallel-type fundamental. Room temperature air-and nitrogen-broadened halfwidths have also been determined for these lines. The average of the ratios of nitrogen- to air-broadened halfwidths was 1.01 with a standard deviation of 0.01, indicating almost equal broadening efficiencies for nitrogen and air. Room temperature self-broadened halfwidths were determined for two transitions with a mean value of $0.081\pm 0.010cm-1atm-1$.