Pressure broadening and shift of some H2O lines in the nu(2) band: Revisited

Pressure-induced line broadening and line shift of three rovibrational transitions in the v(2) band and three in the 2v(2) - v(2) hot band of H2O at 7 mu m were remeasured, using the wavelength-stabilized Cologne diode laser spectrometer with an upgraded recording system: the determination of the absolute line positions was better than 1 MHz, whereas the sensitivity and the long-term stability were improved by at least a factor of 10. The shift coefficient was found to be linearly dependent on the mixing ratio of the foreign gases oxygen and nitrogen for all transitions investigated, including the 13(2,12) <-- 14(1,13) transition for which we previously reported a nonlinear behavior. This greatly improved consistency of the experimental data sets allows a check on the applicability of various profile functions: a comparison between the Galatry and a Voigt profile function with floating Doppler width indicates that both reproduce the experimental values very well. Purely the ease of use gives the edge to the Voigt profile with floating Doppler width. (C) 1997 Academic Press.