Study of Collisional Effects on Band Shapes of the ν1/2ν2 Fermi Dyad in CO2 Gas with Stimulated Raman-Spectroscopy .3. Modeling of Collisional Narrowing and Study of Vibrational Shifting and Broadening at High-Temperature

0021-9606High resolution stimulated Raman spectra (SRS) of the ν1/2ν2 Fermi dyad of CO2 have been recorded in the 0.4-22. amagat density range at 700 K and in the 0.6-16 amagat density range at 900 K. The data have been successfully analyzed with a theoretical model taking into account both rotational line mixing through the energy corrected sudden-polynomial (ECS-P) law for the relaxation matrix and vibrational line broadening gamma(v) and line shifting delta(v). The two vibrational parameters have been accurately determined from fit to the experimental spectra. These new high temperature data together with previous data obtained at 295 and 500 K [B. Lavorel et al., J. Chem. Phys. 93, 2176 (1990); B. Lavorel et al., J. Chem. Phys. 93, 2185 (1990)] entirely determine the temperature dependence in the 295-900 K range of Raman band shapes of ν1 and 2ν2 in a large pressure range. These results will be very useful in CARS thermometry. A few coherent anti-Stokes Raman spectra (CARS) recorded in the 1100-1300 K domain are consistent with extrapolations of the 295-900 K data