F. Thibault et al., Line mixing effects in the nu(3) band of CH3F in helium: Experimental bandshapes and ECS analysis, EUR PHY J D, 6(3), 1999, pp. 343-353
Line mixing effects have been studied in the v(3) band of CH3F perturbed by
helium. Theoretical absorption coefficients are compared to FTIR measureme
nts, which were made at room temperature for helium pressure from 1 atm up
to 90 atm. The observed strong modifications with respect to additive Loren
tzian contributions are explained by line coupling effects. The Infinite Or
der Sudden Approximation and the Energy Corrected Sudden Approximation are
used in order to account for these effects. The latter gives better agreeme
nt: it rather successfully predicts the band shape and the linewidths.