捕光复合物中起源于电子-振动耦合的长时间相干

Long-Lived Coherence Originating from Electronic-Vibrational Couplings in Light-Harvesting Complexes

用精确的数值路径积分技术理论研究了二维、三阶、非线性、光子回波重相位谱随布局时间的演化．研究结果显示，对于同一系统，激子态的相干与弛豫时间很短．若考虑电子与色素振动模式的耦合，则电子一振动态的相干与弛豫的时间大大地延长．这意味着，电子与振动模式的耦合对于捕光复合物保持长时间的相干起了重要作用．利用该方法能够找到生物分子系统能量转移的路径．

We theoretically investigate the evolutions of two-dimensional, third-order, nonlinear photon echo rephasing spectra with population time by using an exact numerical path integral method. It is shown that for the same system, the coherence time and relaxation time of excitonic states are short, however, if the couplings of electronic and intra-pigment vibrational modes are considered, the coherence time and relaxation time of this vibronic states are greatly extended. It means that the couplings between electronic and vibrational modes play important roles in keeping long-lived coherence in light-harvesting complexes. Particularly, by using the method we can fix the transition path of the energy transfer in bio-molecular systems.