Transition dipole interaction in polypeptides: Ab initio calculation of transition dipole parameters

Abstract

Ab initio calculations of dipole moment derivatives of a model system of N-methylacetamide hydrogen-bonded to two formamide molecules give values for amide I and amide II transition dipole moments consistent with those derived from observed band splittings in the spectra of polypeptides. Transition dipole coupling thus provides a reasonable mechanism for explaining these splittings.