Resonance Raman studies of the peptide bond: implications for the geometry of the electronic excited state and the nature of the vibronic linewidth

Bruce S Hudson

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Recent resonance Raman studies of the peptide bond, especially the simple compound N-methylacetamide (NMA), have shown that only a few of the vibrational modes of motion are resonantly enhanced with excitation in the region of the ππ* electronic excitation. The resonance Raman spectra observed for the vapor, acetonitrile solution and aqueous solution are quite distinct. These changes in the Raman spectra with changes in solvent and similar changes seen with N-deuteration are consistent with a variation of the form of the normal modes in the ground electronic state. In the case of solutions of NMA in D2O the resonance Raman spectrum contains only a single strong vibration, the amide II′ mode. The spectra obtained with 200 nm excitation show overtones up to the 0 → 4 transition. This amide II′ vibration shows a 37 cm-1 shift upon 13C-15N isotopic substitution. This indicates that this mode has an important contribution from C-N stretching but normal mode calculations indicate significant components of other degrees of freedom. The available resonance Raman and absorption spectra provide sufficient data to permit a minimal model of the displacement along the active normal mode with electronic excitation.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsSergei A. Akhmanov, Marina Yu. Poroshina
PublisherPubl by Int Soc for Optical Engineering
Pages27-36
Number of pages10
Volume1403
Editionpt 1
StatePublished - 1991
Externally publishedYes
EventInternational Conference on Laser Applications in Life Sciences - Moscow, USSR
Duration: Aug 27 1990Aug 31 1990

Other

OtherInternational Conference on Laser Applications in Life Sciences
CityMoscow, USSR
Period8/27/908/31/90

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ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Hudson, B. S. (1991). Resonance Raman studies of the peptide bond: implications for the geometry of the electronic excited state and the nature of the vibronic linewidth. In S. A. Akhmanov, & M. Y. Poroshina (Eds.), Proceedings of SPIE - The International Society for Optical Engineering (pt 1 ed., Vol. 1403, pp. 27-36). Publ by Int Soc for Optical Engineering.