NH 3 self-broadening coefficients in the ν2 and ν4 bands and line intensities in the ν2 band

Abstract

Self-broadening coefficients of NH 3 in the ν 2 and ν 4 bands and absolute line intensities in the ν 2 band have been measured at room temperature for some selected lines in the P- and R-branches. Using a Fourier transform spectrometer, line intensities and collisional widths were obtained by fitting Voigt profiles to the measured shapes of the lines. The results of self-broadening coefficients are in reasonable agreement with calculated linewidths using a semiclassical model which reproduce rather well the systematic experimental J and K quantum numbers dependencies. Satisfactory agreement was also obtained for line intensities with previous measurements in the ν 2 band. From the intensity measurements, we have determined effective transition dipole moments as well as Herman–Wallis parameters for the ν 2 band.