Energy migration in the light-harvesting antenna of the photosynthetic bacterium Rhodospirillum rubrum studied by time-resolved excitation annihilation at 77 K.
Energy migration in the light-harvesting antenna of the photosynthetic bacterium Rhodospirillum rubrum studied by time-resolved excitation annihilation at 77 K.
复制标题
通过 77 K 下时间分辨激发湮灭研究光合细菌红色红螺菌的光捕获天线中的能量迁移。
DOI：
10.1016/s0006-3495(96)79804-1
复制
发表时间：
1996
影响因子：
3.4
通讯作者：
V. Sundström
中科院分区：
文献类型：
--
作者：
L. Valkunas;E. Åkesson;T. Pullerits;V. Sundström
在77K下，研究了光合细菌Rhodspirillum rubrum捕光天线中皮秒动力学的强度依赖性。通过改变平均激发强度或脉冲强度，我们能够区分单态-单态和单态-三态湮灭。结果表明，这两种湮没类型的动力学均由导致随时间变化的湮没速率的渗流激发动力学概念很好地描述。这两种湮没速率的时间依赖关系本质上是不同的，而依赖关系可以通过相同的可调参数--类分形结构的谱维来关联。当光谱维度等于1.5时，理论依赖关系与实验动力学很好地吻合，并且总的单线态-单线态湮没速率接近于室温下的数值。渗流转移是光谱不均匀展宽的结果。这种影响在较低的温度下更为明显，因为均匀光谱变窄。
The intensity dependence of picosecond kinetics in the light-harvesting antenna of the photosynthetic bacterium Rhodospirillum rubrum is studied at 77 K. By changing either the average excitation intensity or the pulse intensity we have been able to discriminate singlet-singlet and singlet-triplet annihilation. It is shown that the kinetics of both annihilation types are well characterized by the concept of percolative excitation dynamics leading to the time-dependent annihilation rates. The time dependence of these two types of annihilation rates is qualitatively different, whereas the dependencies can be related through the same adjustable parameter-a spectral dimension of fractal-like structures. The theoretical dependencies give a good fit to the experimental kinetics if the spectral dimension is equal to 1.5 and the overall singlet-singlet annihilation rate is close to the value obtained at room temperature. The percolative transfer is a consequence of spectral inhomogeneous broadening. The effect is more pronounced at lower temperatures because of the narrowing of homogeneous spectra.