Non-Uniform Excited State Electronic-Vibrational Coupling of Pigment-Protein Complexes.
Non-Uniform Excited State Electronic-Vibrational Coupling of Pigment-Protein Complexes.
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色素-蛋白质复合物的非均匀激发态电子振动耦合。
DOI：
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发表时间：
2020
影响因子：
5.7
通讯作者：
E. Harel
中科院分区：
文献类型：
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作者：
Shawn Irgen;K. Gururangan;A. Spencer;E. Harel
光合生物利用相互作用的量子自由度，即色素内电子振动（振动）和色素间偶极耦合（J耦合），快速有效地将光转化为化学能。这些相互作用导致波函数配置，使颜料和颜料振动之间的激发离域。我们的研究使用多维光谱比较两种模型光合蛋白，Fenna-Matthews Olson（FMO）复合物和光捕获2（LH 2），并确认长寿命的激发态相干性起源于色素的振动模式。在这个框架内，振动颜料的J-耦合应该具有级联效应，以修改激子态的结构化光谱密度。我们表明，FMO有效地耦合到一个统一的振动集，而在LH 2，它的两个发色团环每个耦合到一个独特的振动环境的所有激发。我们模拟了一个简单的模型系统中的能量转移与非均匀振动耦合，以展示如何修改的振动耦合强度可以调制能量转移。因为增加电子振动耦合增加内部弛豫，所以强耦合电子振动态可以充当能量漏斗，这可以潜在地有益于能量传输。
Photosynthetic organisms exploit interacting quantum degrees of freedom, namely intrapigment electron-vibrational (vibronic) and interpigment dipolar couplings (J-coupling), to rapidly and efficiently convert light into chemical energy. These interactions result in wave function configurations that delocalize excitation between pigments and pigment vibrations. Our study uses multidimensional spectroscopy to compare two model photosynthetic proteins, the Fenna-Matthews Olson (FMO) complex and light harvesting 2 (LH2), and confirm that long-lived excited state coherences originate from the vibrational modes of the pigment. Within this framework, the J-coupling of vibronic pigments should have a cascading effect in modifying the structured spectral density of excitonic states. We show that FMO effectively couples all of its excitations to a uniform set of vibrations while in LH2, its two chromophore rings each couple to a unique vibrational environment. We simulate energy transfer in a simple model system with non-uniform vibrational coupling to demonstrate how modification of the vibronic coupling strength can modulate energy transfer. Because increasing vibronic coupling increases internal relaxation, strongly coupled vibronic states can act as an energy funnel, which can potentially benefit energy transport.
影响因子：
2.9
作者：
Huang, Richard Y-C.;Wen, Jianzhong;Blankenship, Robert E.;Gross, Michael L.
通讯作者：
Gross, Michael L.