| Autor: |
Lampoura, Stefania. S., Krueger, B.P., Van Stokkum, I.H.M., Salverda, J.M., Gradinaru, C.C., Rutkauskas, D., Hiller, R.G., Van Grondelle, R. |
| Předmět: |
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| Zdroj: |
International Journal of Modern Physics B: Condensed Matter Physics; Statistical Physics; Applied Physics; 12/10/2001, Vol. 15 Issue 28-30, p3849, 4p |
| Abstrakt: |
In this work we report the results of ultrafast transient absorption studies which examined energy transfer between carotenoids and chlorophylls in Peridinin-Chlorophyll-α-Protein (PCP) light harvesting complex from the dinofiagellate Amphidinium carterae. Global analysis of the isotropic decay reveals that the peridinin lifetime in PCP is 2.3±0.2 ps. This time constant is the peridinin-Chla energy transfer, which is essentially entirely mediated by coupling of the peridinin S[sub 1] and Chla Q[sub y] transitions. Based on this lifetime we estimated an energy transfer timescale of ∼2.4 ps and a peridinin-Chla coupling of 46 cm[sup -1]. The magnitude of this coupling suggests a peridinin S[sub 1] transition dipole moment of ∼3 D. Global analysis of the depolarization measurements, shows, a small decrease in the depolarization from the initial 0.4 value to 0.36±0.03. This decrease occurs on the same timescale as the S2→S1 internal conversion, suggesting that either the S1 transition dipole is oriented ∼15° away from the S2 transition dipole, or, that a small amount of peridinin S[sub 2]-peridinin S[sub 2] energy transfer occurs in competition with internal conversion, or some combination of the two. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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