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Carotenoids as a Shortcut for Chlorophyll Soret‐to‐Q Band Energy Flow
Author(s) -
Götze Jan P.,
Kröner Dominik,
Banerjee Shiladitya,
Karasulu Bora,
Thiel Walter
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402233
Subject(s) - chemistry , xanthophyll , density functional theory , excited state , violaxanthin , ground state , photochemistry , computational chemistry , zeaxanthin , chemical physics , atomic physics , carotenoid , physics , food science , lutein
It is proposed that xanthophylls, and carotenoids in general, may assist in energy transfer from the chlorophyll Soret band to the Q band. Ground‐state (1A g ) and excited‐state (1B u ) optimizations of violaxanthin (Vx) and zeaxanthin (Zx) are performed in an environment mimicking the light‐harvesting complex II (LHCII), including the closest chlorophyll b molecule (Chl). Time‐dependent density functional theory (TD‐DFT, CAM‐B3LYP functional) is used in combination with a semi‐empirical description to obtain the excited‐state geometries, supported by additional DFT/multireference configuration interaction calculations, with and without point charges representing LHCII. In the ground state, Vx and Zx show similar properties. At the 1B u minimum, the energy of the Zx 1B u state is below the Chl Q band, in contrast to Vx. Both Vx and Zx may act as acceptors of Soret‐state energy; transfer to the Q band seems to be favored for Vx. These findings suggest that carotenoids may generally mediate Soret‐to‐Q energy flow in LHCII.