Raman intensities of overtones. Analysis of 2ν4 band of cyanogen

Formulas for the absolute differential Raman scattering cross section of overtones of doubly and triply degenerate fundamentals as a function of molecular invariants are reported. The absolute cross section and the depolarization ratio of 2ν4(Σ+g+Δg) of cyanogen are interpreted in terms of the bond polarizability theory and of the ℒ-tensor formulation of Hoy, Mills and Strey. It is shown also, how the analysis of Raman intensities of overtones and/or combination bands supplies valuable information to solve for most ambiguities on signs and multiplicity of solutions of bond polarizability parameters arising from the analysis of the Raman intensities of vibrational fundamentals.