Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria
Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria
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DOI：
10.1007/s11120-014-9978-7
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发表时间：
2014-06-01
影响因子：
3.7
通讯作者：
Aspuru-Guzik, Alan
中科院分区：
文献类型：
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作者：
Fujita, Takatoshi;Huh, Joonsuk;Aspuru-Guzik, Alan
基于最近提出的分子组装模型，我们对绿色光合细菌的绿体天线复合体中的激发动力学进行了理论研究。我们的整个天线的激发能量转移(EET)模型结合了激子波函数的随机时间传播、超分子结构的分子动力学模拟和激发态的电子结构计算。我们用吸收光谱、圆二色谱和荧光偏振各向异性衰变光谱表征了绿小体的光学性质。对激发动力学的模拟结果揭示了绿小体中EET的详细图像。相干能量传递仅在初始激发后的前50fs内显著，而激子的波状运动在100fs时完全被抑制。随后，非相干能量转移的特征时间常数从1ps到几十ps变化。我们通过将我们的结果与时间分辨光谱实验获得的数据进行比较，将EET的时间尺度指定为特定的物理过程。
We present a theoretical study of excitation dynamics in the chlorosome antenna complex of green photosynthetic bacteria based on a recently proposed model for the molecular assembly. Our model for the excitation energy transfer (EET) throughout the antenna combines a stochastic time propagation of the excitonic wave function with molecular dynamics simulations of the supramolecular structure and electronic structure calculations of the excited states. We characterized the optical properties of the chlorosome with absorption, circular dichroism and fluorescence polarization anisotropy decay spectra. The simulation results for the excitation dynamics reveal a detailed picture of the EET in the chlorosome. Coherent energy transfer is significant only for the first 50 fs after the initial excitation, and the wavelike motion of the exciton is completely damped at 100 fs. Characteristic time constants of incoherent energy transfer, subsequently, vary from 1 ps to several tens of ps. We assign the time scales of the EET to specific physical processes by comparing our results with the data obtained from time-resolved spectroscopy experiments.