Solution-Phase Raman Studies of Alanyl Dipeptides and Various Isotopomers: A Reevaluation of the Amide III Vibrational Assignment

Article abstract of DOI:10.1021/j150647a036

Solution-phase Raman spectra of L-alanyl-L-alanine and five nitrogen and/or α-deuterated isotopomers are reported.Detailed vibrational assignments on this set of spectra have led to a somewhat different interpretation of the amide III vibrational region, as compared to literature assignments.The differences result from the fact that, in these deuterated samples, the nature of certain vibrations, and their interactions with other vibrations of similar energies, may be investigated with very high sensitivity.A discussion of the observed interaction of the amide III vibration and the methine deformation is presented, leading to an explanation for the geometric sensitivity of the band commonly referred to as the "amide III" mode.