%0 Journal Article
%A Trinkunas, Gediminas
%A Zerlauskiene, Oksana
%A Urbonienė, Vidita
%A Chmeliov, Jevgenij
%A Gall, Andrew
%A Robert, Bruno
%A Valkunas, Leonas
%D 2016
%T Exciton Band Structure
in Bacterial Peripheral Light-Harvesting
Complexes
%U https://acs.figshare.com/articles/journal_contribution/Exciton_Band_Structure_in_Bacterial_Peripheral_Light_Harvesting_Complexes/2526250
%R 10.1021/jp302042w.s001
%2 https://ndownloader.figshare.com/files/4169245
%K temperature dependence
%K photosynthetic bacteria Rba
%K B 850 ring
%K photosynthetic bacteria Rhodobacter
%K exciton spectra formation
%K intradimer resonance interaction values
%K Exciton Band Structure
%K LH 2 complexes
%K absorption spectra
%K exciton bandwidth
%X The variability of the exciton spectra of bacteriochlorophyll
molecules
in light-harvesting (LH) complexes of photosynthetic bacteria ensures
the excitation energy funneling trend toward the reaction center.
The decisive shift of the energies is achieved due to exciton spectra
formation caused by the resonance interaction between the pigments.
The possibility to resolve the upper Davydov sub-band corresponding
to the B850 ring and, thus, to estimate the exciton bandwidth by analyzing
the temperature dependence of the steady-state absorption spectra
of the LH2 complexes is demonstrated. For this purpose a self-modeling
curve resolution approach was applied for analysis of the temperature
dependence of the absorption spectra of LH2 complexes from the photosynthetic
bacteria Rhodobacter (Rba.) sphaeroides and Rhodoblastus (Rbl.) acidophilus. Estimations of the intradimer
resonance interaction values as follows directly from obtained estimations
of the exciton bandwidths at room temperature give 385 and 397 cm–1 for the LH2 complexes from the photosynthetic bacteria Rba. sphaeroides and Rhl. acidophilus,
respectively. At 4 K the corresponding couplings are slightly higher
(391 and 435 cm–1, respectively). The retained exciton
bandwidth at physiological conditions supports the decisive role of
the exciton coherence determining light absorption in bacterial light-harvesting
antenna complexes.
%I ACS Publications