Interpretation of the vibrational modes of uracil and its ¹⁸O‐substituted and thio derivatives studied by resonance Raman spectroscopy

Abstract

Abstract On the basis of a valence force field, the frequencies of the vibrational modes of uracil and its 18 O derivatives substituted in the 2‐, the 4‐ and the 2, 4‐positions, have been calculated. The frequencies are compared with those available from the ultraviolet resonance Raman spectra. The resonance Raman bands observed experimentally in the spectra of the uracil 2‐, 4‐ and 2, 4‐dithio derivatives have been calculated with an equivalent extended force field, and a tentative assignment of these lines is proposed.