scholarly journals Transition-density-fragment interaction combined with transfer integral approach for excitation-energy transfer via charge-transfer states

2012 ◽  
Vol 137 (3) ◽  
pp. 034101 ◽  
Author(s):  
Kazuhiro J. Fujimoto
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Excitation Energy Transfer ◽  
Transition Density ◽  
Integral Approach ◽  
Transfer Integral ◽  
Fragment Interaction

Charge transfer-induced assembly of a gold nanocomposite mediated by N-methylfulleropyrrolidine: excitation energy transfer from Rhodamine B

2017 ◽  
Vol 41 (6) ◽  
pp. 2401-2408 ◽  
Author(s):  
Sanjeeb Sutradhar ◽  
Archita Patnaik
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Rhodamine B ◽  
Excitation Energy Transfer ◽  
Aurophilic Interactions ◽  
Composite Self ◽  
Energy Acceptor ◽  
Ph Controlled

A pH controlled functionalized fullerene-C60-gold NP composite self-assembles via electrostatic as well as aurophilic interactions and acts as an excitation energy acceptor from fluorescent Rhodamine B (3.79 × 6.5 inch).

scholarly journals Chlorophyll–carotenoid excitation energy transfer and charge transfer in Nannochloropsis oceanica for the regulation of photosynthesis

2019 ◽  
Vol 116 (9) ◽  
pp. 3385-3390 ◽  
Author(s):  
Soomin Park ◽  
Collin J. Steen ◽  
Dagmar Lyska ◽  
Alexandra L. Fischer ◽  
Benjamin Endelman ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Transient Absorption ◽  
Excitation Energy Transfer ◽  
Excited State Absorption ◽  
Thermal Dissipation ◽  
Live Cells ◽  
Nannochloropsis Oceanica

Nonphotochemical quenching (NPQ) is a proxy for photoprotective thermal dissipation processes that regulate photosynthetic light harvesting. The identification of NPQ mechanisms and their molecular or physiological triggering factors under in vivo conditions is a matter of controversy. Here, to investigate chlorophyll (Chl)–zeaxanthin (Zea) excitation energy transfer (EET) and charge transfer (CT) as possible NPQ mechanisms, we performed transient absorption (TA) spectroscopy on live cells of the microalga Nannochloropsis oceanica. We obtained evidence for the operation of both EET and CT quenching by observing spectral features associated with the Zea S1 and Zea●+ excited-state absorption (ESA) signals, respectively, after Chl excitation. Knockout mutants for genes encoding either violaxanthin de-epoxidase or LHCX1 proteins exhibited strongly inhibited NPQ capabilities and lacked detectable Zea S1 and Zea●+ ESA signals in vivo, which strongly suggests that the accumulation of Zea and active LHCX1 is essential for both EET and CT quenching in N. oceanica.

scholarly journals Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids

2017 ◽  
Vol 198 ◽  
pp. 59-71 ◽  
Author(s):  
Nao Yukihira ◽  
Yuko Sugai ◽  
Masazumi Fujiwara ◽  
Daisuke Kosumi ◽  
Masahiko Iha ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Brown Algae ◽  
Light Harvesting ◽  
Excitation Energy Transfer ◽  
Light Harvesting Complexes ◽  
Light Harvesting Complex ◽  
Molecular Charge ◽  
Intra Molecular Charge Transfer

Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (∼95%) energy-transfer from fucoxanthin to chlorophyllain the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids. In this study we were successful, for the first time, in incorporating fucoxanthin into a light-harvesting complex 1 from the purple photosynthetic bacterium,Rhodospirillum rubrumG9+ (a carotenoidless strain). Femtosecond pump-probe spectroscopy was applied to this reconstituted light-harvesting complex in order to determine the efficiency of excitation energy-transfer from fucoxanthin to bacteriochlorophyllawhen they are bound to the light-harvesting 1 apo-proteins.

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