To calculate H₂O and CO₂ line broadening and shifting induced by nitrogen pressure the impact theory has been modified on the wider use of empiric data by introducing of the additional parameters taking into account the trajectory bending, effects of vibrational excitation, corrections to the scattering matrix obtained from the perturbation theory, etc. Model parameters were determined by fitting the broadening coefficients to experimental data. This allows sufficiently accurate prediction of the parameters of line profiles, which were not measured. Our calculated data are in satisfactory agreement with the measurements. The measured broadening coefficients also show the same trend as the calculated ones. According to developed approach the numerous calculations were performed, which allow one to make the conclusion that the calculations performed by our semiempiric method give reasonable description of water vapor and carbon dioxide line parameters induced by nitrogen pressure. As in our previous work on the water vapor line shifts in the R-branch of the v₂ band we have analysed the J-dependence of the halfwidths in a wide range of quantum numbers (up to J=15). The analysis shows that the halfwidths dependence as a function of the rotational quantum numbers have a more complicated character than it was assumed earlier. The halfwidths have an overall tendency to decrease with J for low K_a quantum numbers, but they are stable or even slightly increasing with J for large K_a.

Date Published: 12 January 2004
PDF: 11 pages
Proc. SPIE 5311, 14th Symposium on High-Resolution Molecular Spectroscopy, (12 January 2004); doi: 10.1117/12.545672

Published in SPIE Proceedings Vol. 5311:
14th Symposium on High-Resolution Molecular Spectroscopy
Leonid N. Sinitsa; Semen N. Mikhailenko, Editor(s)