Measurements of Lorentz-broadening coefficients and pressure-induced line shift coefficients in the ν2 band of D 216O

Abstract

Room temperature Lorentz-broadening coefficients and pressure-induced line shift coefficients in air, nitrogen, and oxygen have been determined for 126 transitions in the ν 2 band of D 2 16O from laboratory spectra recorded at 0.0053-cm −1 resolution with a Fourier transform spectrometer. Samples of D 2O + HDO + H 2O at low pressure (≤1 Torr) and lean mixtures of D 2O + HDO + H 2O broadened by nitrogen, oxygen, and air were used in the experiments. Transitions up to J″ = 12 were measured using a nonlinear least-squares fitting procedure assuming a Voigt line profile. The broadening coefficients obtained for the three buffer gases generally decrease with increasing J″. The ratio of the nitrogen-broadening coefficient to the corresponding oxygen-broadening coefficient is correlated with the magnitude of the oxygen-broadening coefficient (the narrower lines have the larger N 2-to-O 2 broadening ratios). The pressure-shift coefficients are both positive and negative with values in the range −0.008 to +0.008 cm −1 atm −1; no significant correlation with the widths was found. The results are compared with previously reported measurements.