Preresonance Raman spectra of simple amides using ultraviolet lasers

The Raman spectra of N ‐methylacetamide, N ‐ethylacetamide, and N ‐methylpropionamide have been recoraed using the laser lines at 6471 Å, 4765 Å, 4762 Å, 3507 Å. and 2573 Å for excitation. Appreciable intensity enhancement has been observed for the amide I and III lines in the UV excited spectra; the amide II lines show up clearly in the spectra using 2573 Å excitation, and the G ‐methyl and N ‐methyl symmetric deformation lines are also enhanced. The possible usefulness of the Raman spectra of peptide molecules obtained using ultraviolet excitation is discussed.