Zirak, P. and Penzkofer, Alfons and Mathes, T. and Hegemann, P. (2009) Photo-dynamics of roseoflavin and riboflavin in aqueous and organic solvents. CHEMICAL PHYSICS, 358 (1-2). pp. 111-122. ISSN 0301-0104, 1873-4421
Full text not available from this repository. (Request a copy)Abstract
Roseoflavin (8-dimethylamino-8-demethyl-D-riboflavin) and riboflavin in aqueous and organic solvents are studied by optical absorption spectroscopy, fluorescence spectroscopy, and fluorescence decay kinetics. Solvent polarity dependent absorption shifts are observed. The fluorescence quantum yields are solvent dependent. For roseoflavin the fluorescence decay shows a bi-exponential dependence (ps to sub-ps time constant, and 100 ps to a few ns time constant). The roseoflavin photo-dynamics is explained in terms of fast intra-molecular charge transfer (diabatic electron transfer) from the dimethylamino electron donor group to the pteridin carbonyl electron acceptor followed by intra-molecular charge recombination. The fast fluorescence component is due to direct locally-excited-state emission, and the slow fluorescence component is due to delayed locally-excited-state emission and charge transfer state emission. The fluorescence decay of riboflavin is mono-exponential. The S-1-state potential energy surface is determined by vibronic relaxation and solvation dynamics due to excited-state dipole moment changes (adiabatic optical electron transfer). (c) 2009 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | INTRAMOLECULAR CHARGE-TRANSFER; SPECTRAL PROPERTIES; LACTOCOCCUS-LACTIS; SOLVATION DYNAMICS; EMISSION BEHAVIOR; BACILLUS-SUBTILIS; ELECTRON-TRANSFER; COENZYME MODELS; DYE VAPORS; ABSORPTION; Roseoflavin; Riboflavin; Absorption spectroscopy; Fluorescence spectroscopy; Fluorescence kinetics; Dual fluorescence; Intra-molecular charge transfer; Locally-excited-state emission; Charge transfer state emission; Charge recombination |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 21 Sep 2020 06:25 |
| Last Modified: | 21 Sep 2020 06:25 |
| URI: | https://pred.uni-regensburg.de/id/eprint/29252 |
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