Non-radiative relaxation of photoexcited chlorophylls [electronic resource] : Theoretical and experimental study

Published:: Washington, D.C. : United States. Dept. of Energy. Office of Basic Energy Sciences, 2015.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description:: Article numbers 13,625 : digital, PDF file
Additional Creators:: Sandia National Laboratories, United States. Department of Energy. Office of Basic Energy Sciences, and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

Nonradiative relaxation of high-energy excited states to the lowest excited state in chlorophylls marks the first step in the process of photosynthesis. We perform ultrafast transient absorption spectroscopy measurements, that reveal this internal conversion dynamics to be slightly slower in chlorophyll B than in chlorophyll A. With modeling this process, non-adiabatic excited state molecular dynamics simulations uncovers a critical role played by the different side groups in the two molecules in governing the intramolecular redistribution of excited state wavefunction, leading, in turn, to different time-scales. Even given smaller electron-vibrational couplings compared to common organic conjugated chromophores, these molecules are able to efficiently dissipate about 1 eV of electronic energy into heat on the timescale of around 200 fs. This is achieved via selective participation of specific atomic groups and complex global migration of the wavefunction from the outer to inner ring, which may have important implications for biological light-harvesting function.

Report Numbers:

E 1.99:1222484

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Note:

Published through SciTech Connect.
09/08/2015.
"srep13625"
Scientific Reports 5 ISSN 2045-2322 AM
Bricker, William; Shenai, Prathamesh; Ghosh, Avishek; Liu, Zhengtang; Enriquez, Miriam; Lambrev, Petar; Tan, Howe; Lo, Cynthia; Tretiak, Sergei; Fernandez-Alberti, Sebastian; Zhao, Yang.

Funding Information:

AC52-06NA25396

View MARC record | catkey: 23499431