The effect of inhomogeneous broadening on the absorption spectra and excitation profiles of resonance Raman and coherent anti‐stokes Raman scattering of polyatomic molecules

A uniform treatment of the effect of inhomogeneous broadening on the absorption spectra and the excitation profiles of resonance Raman scattering and coherent anti‐Stokes Raman scattering is presented. For the case of Gaussian distribution of molecular energy values general expressions are obtained which are valid for arbitrary values of homogeneous and inhomogeneous broadening parameters. Just as for resonance Raman scattering excitation profiles, the coherent anti‐Stokes Raman scattering excitation profiles are quite sensitive to the mechanism of vibronic line broadening. The simple relation between resonance Raman scattering and coherent anti‐Stokes Raman scattering excitation profiles is shown to be valid only if the effect of inhomogeneous broadening is negligible. We suggest that this fact should be used for experimental estimation of the impact of inhomogeneous broadening. We discuss the possibility of using absorption data as well as resonance Raman scattering and coherent anti‐Stokes Raman scattering excitation profiles for testing the adequacy of the original model of vibronic theory.