Quantum-mechanical calculation of the intensity distribution in resonance Raman spectra of thiosubstituted derivatives of uracil

A quantum-mechanical calculation of the intensity distribution in the resonance Raman (RR) spectra of 2-thiouracil and 4-thiouracil is carried out for exciting laser radiation at 300, 257, and 248 nm. It is shown that, for satisfactory agreement between the calculated results and the experimental data, it is necessary to take into account in the calculations of the relative intensities of lines the Herzberg-Teller effect and the contribution from excited electronic states adjacent to the resonance state. The general and specific features of the intensity distribution in the RR spectra of uracil and its thiosubstituted derivatives are compared and discussed.