Acoustic excitation was used to determine the adiabatic pressure derivative of the spectral absorptance of the 2.7 and 1.9 µm water vapor bands and its dependence upon the thermodynamic parameters concentration, pressure, and temperature. The spectral absorptance was measured accurately using a cross-flow water vapor system. Our low-resolution results agree well with spectra calculated from the parameters characterizing the individual rotational lines. The “F factor” corrections found for the 2.7 µm band agree with F values quoted for individual lines. We estimated the 1.9 µm band F factor. Absorptance and thermodynamic derivative spectra were also calculated for the 3.5 µm HCl band. In the wings of each band a wavelength can be found where the concentration dependence is predominant. Somewhat farther out in the wings, a local maximum occurs for the temperature derivative. In the core of the band the pressure derivative is significant.
© 1977 Optical Society of America
C. V. Mathai, W. L. Walls, and S. Broersma , "Adiabatic pressure dependence of the 2.7 and 1.9 µm water vapor bands," J. Opt. Soc. Am. 67, 1532-1537 (1977)