DIODE-LASER MEASUREMENTS OF TEMPERATURE-DEPENDENT LINE PARAMETERS FOR WATER-VAPOR NEAR 820-NM

Air- and self-broadening coefficients and relative fine strengths for 8-10 low-J lines in the (21 1) vibrational band of water vapor have been accurately measured over the T = 330-540 K range using an 817-824 nm GaAlAs diode laser. The technique of wavelength modulation with third-harmonic line locking and second-harmonic detection was used to derive the fine parameters with accuracies of several percent from measurements with absorptivities as low as 2 x 10(-3). The linewidths and temperature coefficients are in good agreement with theoretical calculations and with recent measurements in the (2 2 1) and (3 0 1) bands. Absolute line strengths have been derived from measurements on two of the lines and are found to be 21 +/- 4% higher than the values listed in the 1991 HITRAN compilation.