The vibrational frequencies of the N-methylacetamide chain complexes w
ere computed using the perturbation theory. The amide modes of the hyd
rogen-bonded n-mers were studied. The correlations among the resonance
coupling interactions and the dispersion curves of the amide modes we
re discussed. Comparison with experimental IR and Raman spectra on ami
des aggregation in solution and in hydrocarbon matrix indicate that in
formation about chain length and structure may be obtained. (C) 1997 E
lsevier Science B.V.