Measurements and analysis (using empirical functions for widths) of air- and self-broadening parameters of H2O

High-resolution spectra of H2O were recorded with the McMath Fourier-transform spectrometer at the National Solar Observatory located at Kitt Peak, AZ. Seventeen laboratory spectra of water plus air mixtures were recorded at a spectral resolution of 0.01 cm-1 covering the region between 2800 and 8000 cm-1. Over 4000 linewidth and pressure-induced frequency shift coefficients were derived from the spectral data with sample temperatures near or at room temperature (296 K). The measurements include transitions of H2 16O, H2 17O, and H2 18O with the rare oxygen species observed in normal H2O gas samples. The measurements were analyzed with consideration of collision-narrowing effects. The analysis required a knowledge of the self-broadened linewidth coefficients, and the data measured and reported in the previous study were used along with earlier results for this purpose. The self-broadened and air-broadened measured linewidth coefficients obtained here as well as those reported in earlier studies covering the 600-2400 cm-1, were fitted to an empirical expression which contains up to 28 terms. Two fitting procedures were used: one considered the fit of families of transitions and the other was more global in scope. The computed linewidth coefficients derived from the fitted parameters are compared statistically to measurements in this work as well as other studies.