ULTRAFAST DYNAMICS OF LIGHT HARVESTING COMPLEXES

超快各向异性变化的测定可能具有重要意义 在确定能量如何在不同的辅因子之间流动时的价值 一次集会 各向异性测量技术已被 进行了重大改进， 可以高精度地确定能量转移的量。 飞秒 细菌二聚体亚单位内的瞬时动力学 已经使用魔角研究了捕光复合物， 偏振泵浦探测光谱学 170 cm-1和~ 20 cm-1的振荡 在各向同性信号中观察到50 cm-1和115 cm-1， 500 cm-1的各向异性。 的斯托克斯位移和退相 二聚体激子能级出现在低于50 fs的时间尺度上。 的 重新组装的聚集体表现出超快的光谱演化， 双相各向异性衰减 总的来说，这些结果支持了一种观点， LH-1复合物内的能量迁移， 二聚体亚基的状态之间的散射激发转移。

The determination of ultrafast anisotropy changes can be of great value in determining how energy flows between different cofactors in an assembly. The techniques of anisotropy measurement have been significantly refined in order that coherent and orientational aspects of energy transfer can be determined with high accuracy. Femtosecond transient dynamics within the dimeric subunit of a bacterial light-harvesting complex have been investigated using magic angle and polarized pump-probe spectroscopy. Oscillations of 170 cm-1 and ~ 20 cm-1, 50 cm-1 and 115 cm-1 are observed in the isotropic signal and ~ 500 cm-1 in the anisotropy. The Stokes shift and dephasing of the dimer exciton levels occurs on a sub-50 fs timescale. The re-assembled aggregate exhibits ultrafast spectral evolution and biphasic anisotropy decay. Collectively, the results support a view of energy migration within LH-1 complexes as proceeding by strongly scattered excitation transfer between states of the dimeric subunits.