CO2 Pressure Shift and Broadening of Water Lines Near 790 nm

Carbon dioxide pressure-broadened ro-vibrational transitions belonging to the v(2)+3v(3) band of (H2O)-O-16 have been measured with a sensitive cavity ring-down spectrometer. Water vapor of relatively low pressures (<0.5 Torr) wag used to limit the self-collisions among water molecules. After the calibration using the precise atomic transitions of Rb and a thermostabilized Fabry-Perot interferometer, 10(-5) cm(-1) frequency accuracy has been achieved. Line parameters are derived from least-squares fitting of the spectra using the "soft" collision model. The retrieved line parameters can be applied in the study of water absorption in the CO2-rich atmospheres of planets like Venus and Mars.