TY  - JOUR
A1  - Goetze, Jan P.
A1  - Kröner, Dominik
A1  - Banerjee, Shiladitya
A1  - Karasulu, Bora
A1  - Thiel, Walter
T1  - Carotenoids as a shortcut for chlorophyll Soret-to-Q band energy flow
JF  - ChemPhysChem : a European journal of chemical physics and physical chemistry
N2  - 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 1Bu 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.
KW  - carotenoids
KW  - chlorophyll
KW  - density functional calculations
KW  - energy transfer
KW  - xanthophylls
Y1  - 2014
U6  - https://doi.org/10.1002/cphc.201402233
SN  - 1439-4235
SN  - 1439-7641
VL  - 15
IS  - 15
SP  - 3391
EP  - 3400
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Banerjee, Shiladitya
A1  - Kröner, Dominik
A1  - Saalfrank, Peter
T1  - Resonance Raman and vibronic absorption spectra with Duschinsky rotation from a time-dependent perspective application to beta-carotene
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - The time-dependent approach to electronic spectroscopy, as popularized by Heller and co-workers in the 1980s, is applied here in conjunction with linear-response, time-dependent density functional theory to study vibronic absorption and resonance Raman spectra of beta-carotene, with and without a solvent. Two-state models, the harmonic and the Condon approximations are used in order to do so. A new code has been developed which includes excited state displacements, vibrational frequency shifts, and Duschinsky rotation, i.e., mode mixing, for both non-adiabatic spectroscopies. It is shown that Duschinsky rotation has a pronounced effect on the resonance Raman spectra of beta-carotene. In particular, it can explain a recently found anomalous behaviour of the so-called nu(1) peak in resonance Raman spectra [N. Tschirner, M. Schenderlein, K. Brose, E. Schlodder, M. A. Mroginski, C. Thomsen, and P. Hildebrandt, Phys. Chem. Chem. Phys. 11, 11471 (2009)], which shifts with the change in excitation wavelength.
Y1  - 2012
U6  - https://doi.org/10.1063/1.4748147
SN  - 0021-9606
VL  - 137
IS  - 22
PB  - American Institute of Physics
CY  - Melville
ER  -