Measurements of (12)CH4 nu4 band halfwidths using a tunable diode laser system and a Fourier transform spectrometer.

Air-broadened and N2-broadened halfwidths at room temperature for twenty-five transitions in the 4 fundamental band of '2CH4 have been determined from IR absorption spectra recorded with a tunable diode laser spectrometer. Two tunable diode lasers operating in the 1250-1380-cm(-1) region were used to obtain these data. Air-broadened halfwidths for twenty of these lines were also determined from additional spectra recorded at 0.01-cm(-1) resolution with the Fourier transform spectrometer in the McMath solar telescope complex on Kitt Peak. The air-broadened halfwidths obtained from these two techniques are very consistent with agreement better than 3% in most cases.