STUDY OF COLLISIONAL EFFECTS ON BAND SHAPES OF THE NU(1) 2-NU(2) FERMI DYAD IN CO2 GAS WITH STIMULATED RAMAN-SPECTROSCOPY .3. MODELING OF COLLISIONAL NARROWING AND STUDY OF VIBRATIONAL SHIFTING AND BROADENING AT HIGH-TEMPERATURE/

High resolution stimulated Raman spectra (SRS) of the upsilon(1)/2 ups ilon(2) Fermi dyad of CO2 have been recorded in the 0.4-22. amagat den sity range at 700 K and in the 0.6-16 amagat density range at 900 K. T he data have been successfully analyzed with a theoretical model takin g into account both rotational line mixing through the energy correcte d sudden-polynomial (ECS-P) law for the relaxation matrix and vibratio nal line broadening gamma(upsilon) and line shifting delta(upsilon). T he 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. C hem. 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 upsilon(1) and 2 upsilon(2) 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 dat a.