Raman Spectra of Carbon Dioxide and Its Isotopic Variants in the Fermi Resonance Region: Part III. Analysis of Rovibrational Intensities for 12C16O2, 13C16O2, 12C18O2 and 12C16O18O

The present work deals with the intensity analysis of rovibrationally resolved Raman spectra of natural and 13C as well as 18O isotopically enriched samples of CO2 photoelectrically recorded in the Fermi resonance region (1100–1460 cm−1). Based upon Chedin's set of rovibrational data [1] and upon the polarizability theory of Raman scattering, we have successfully fitted our calculated intensities to the measured spectra of each isotopic species. — The procedure yields values for three parameters, namely (δ2ƒ-I0/δq2,+ ;δq2,-) (δƒ-I0/δq1) = - 0.200 and - 0.100 (± 3%) for t = 0 and t = 2, respectively, and |(δƒ-00/& dgr;q1/δ ƒ-20/δq1)| ≈ 1.47 ± 2%, that are derived from the spherical polarizability tensor ƒ-Iq. A spectroscopic temperature can be evaluated within error limits of less than ± 1%.