Line mixing in the ν₃ and forbidden ν₂ bands of CH₄ in gaseous helium

Abstract

The paper reports on studies of the possibility of the transfer of the adjustable parameters of the line mixing model describing the ν₃ absorption band shape of CH₄ in helium to the case of the forbidden ν₂ band shape. This transfer provides a reasonable overall agreement with the measured spectra, with deviations greater than the experimental uncertainties remaining in some J-manifolds. The model has been improved by taking into account the mixing of spectral lines with the same initial level. It was found that the description of the shapes of certain manifolds can be improved by fitting corresponding matrix elements of the optical rotational relaxation matrix, providing, in some particular cases, more detailed information on the matrix structure.

Acknowledgement

This work was supported in part by the Russian Foundation for Basic Research (Grant No. 05-03-32227).