- Author
- Year
- 2009
- Title
- Vibrational self-trapping in beta-sheet structures observed with femtosecond nonlinear infrared spectroscopy
- Journal
- Journal of Chemical Physics
- Volume | Issue number
- 131 | 12
- Pages (from-to)
- 6
- Number of pages
- 124503
- Document type
- Article
- Faculty
- Faculty of Science (FNWI)
- Institute
- Van 't Hoff Institute for Molecular Sciences (HIMS)
- Abstract
-
Self-trapping of NH-stretch vibrational excitations in synthetic beta-sheet helices is observed using femtosecond infrared pump-probe spectroscopy. In a dialanine-based beta-sheet helix, the transient-absorption change upon exciting the NH-stretch mode exhibits a negative absorption change at the fundamental frequency and two positive peaks at lower frequencies. These two induced-absorption peaks are characteristic for a state in which the vibrational excitation is self-trapped on essentially a single NH-group in the hydrogen-bonded NH center dot center dot center dot OC chain, forming a small (Holstein) vibrational polaron. By engineering the structure of the polymer we can disrupt the hydrogen-bonded NH center dot center dot center dot OC chain, allowing us to eliminate the self-trapping, as is confirmed from the NH-stretch pump-probe response. We also investigate a trialanine-based beta-sheet helix, where each side chain participates in two NH center dot center dot center dot OC chains with different hydrogen-bond lengths. The chain with short hydrogen bonds shows the same self-trapping behavior as the dialanine-based beta-sheet helix, whereas in the chain with long hydrogen bonds the self-trapping is too weak to be observable.
- URL
- go to publisher's site
- Language
- Undefined/Unknown
- Persistent Identifier
- https://hdl.handle.net/11245/1.312498
- Downloads
-
312498.pdf(Final published version)
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