کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5404191 1505932 2006 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Spectral hole burning at the low-energy absorption edge of photosystem II core complexes
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Spectral hole burning at the low-energy absorption edge of photosystem II core complexes
چکیده انگلیسی

Photosystem II (PSII) core complexes capable of efficient oxygen evolution at physiological temperatures remain strongly photo-active at low temperatures, where illumination converts the sample to very long-lived (102-5 s) charge-separated configurations via reduction of the plastoquinone, QA. Persistent spectral hole burning (PSHB) seen in the 690-704 nm range exhibits efficiencies comparable to that of QA− formation. The rate of spontaneous spectral hole filling for a hole burnt near 690 nm matches the rate for spontaneous recombination of the charge-separated configuration. This result supports the proposed hole-burning mechanism due to the charge separation that occurs following relatively slow transfer of excitation from selectively excited antenna pigments. Clipping and attenuation of the pseudo-phonon sideband hole establishes that absorption of CP47 antenna chlorophyll a (chl a) in PSII becomes negligible beyond 704 nm. Excitation in the 704-730 nm region lead to no measurable PSHB, despite this illumination inducing photo-conversion in up to 80% of all PSII centers in the sample. We also present illumination-induced changes of the absorption in the 700-730 nm region, and show that they are not associated with PSBH.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Luminescence - Volumes 119–120, July–October 2006, Pages 298-303
نویسندگان
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