期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1972
卷号：69
期号：10
页码：2788-2792
DOI：10.1073/pnas.69.10.2788
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Previous perturbation treatments of the Amide I vibrations of {beta} polypeptides are inconsistent with a detailed normal coordinate analysis of crystalline polyglycine I. This analysis indicates that the D10 interaction constant is essentially zero, rather than the large value (about 20 cm-1) required by the earlier application of the perturbation theory. It is suggested that the previously neglected D11 term should be included in the perturbation expression, and it is shown that the physical origin of such a term can be accounted for by transition dipole coupling. This mechanism is shown to give a reasonable explanation of splittings of the C=O stretching vibrations in hydrogenbonded carboxylic acid dimers. Its application to {beta} polypeptides provides a satisfactory interpretation of splittings in the Amide I modes.
