0000000000924402
AUTHOR
J.p. Berger
H2-He vibrational line-shape parameters: Measurement and semiclassical calculation
High-resolution inverse Raman spectroscopy has been used to obtain the line shifting and line broadening coefficients of H{sub 2} perturbed by He. Measurements have been made for the {ital Q}-branch transitions ({ital J}=0{r_arrow}5) in a density range of 10 to 20 amagat and from 296 to 995 K. Up to 795 K we have directly deduced from the experimental broadening coefficients the inelastic rotational state-to-state and vibrational dephasing rates. At higher temperatures, owing to the larger number of channels of relaxation which occur, the results have been analyzed using a scaling law. The line shift and broadening coefficients exhibit a square root and a linear dependence on temperature, r…
Collisional broadening and shifting parameters of the RamanQbranch ofH2perturbed byN2determined from speed-dependent line profiles at high temperatures
The broadening and shifting of the {ital Q} branch of H{sub 2} diluted in N{sub 2} are studied at temperatures between 300 and 1200 K. (i) In order to account for the observed anomalies (asymmetric profiles and nonlinearity of the linewidth versus perturber concentration), the results are interpreted using a speed-dependent model in its general form. This model introduces the speed dependence of the shift and the broadening. In contrast with the previous H{sub 2}{endash}rare-gas studies, the high-temperature measurements prove the necessity to include speed-dependent broadening that was ignored in the previous studies. (ii) Concomitantly, we report as well pure H{sub 2} results including Ra…