Vol. 15, issue 09, article # 7

Abstract:

Nitrogen pressure induced shift coefficients for water vapor absorption lines in the spectral region from 5000 to 5600 cm^-1 have been measured and calculated. Experimental data on line shift coefficients were obtained from the H₂O-N₂ absorption spectra at room temperature. The spectra were recorded throughout a wide range of buffer gas pressure with a Fourier transform spectrometer having the spectral resolution of 0.007 cm^-1 and an optical path length of 84.05 m. The line shift coefficients were calculated using semiclassical impact theory by Anderson and only one parameter fitted, i.e., the mean dipole polarizability of the upper vibrational state. The shifts of the same lines induced by pressure of different buffer gases were compared, and the roles of different terms of the intermolecular potential in the formation of line shifts were studied.