Cho Minhaeng, Vaswani Harsha M, Brixner Tobias, Stenger Jens, Fleming Graham R
Department of Chemistry and Center for Multidimensional Spectroscopy, Division of Chemistry and Molecular Engineering, Korea University, Seoul 136-701, Korea.
J Phys Chem B. 2005 Jun 2;109(21):10542-56. doi: 10.1021/jp050788d.
A theoretical description of femtosecond two-dimensional electronic spectroscopy of multichromophoric systems is presented. Applying the stationary phase approximation to the calculation of photon echo spectra and taking into account exciton relaxation processes, we obtain an analytic expression for numerical simulations of time- and frequency-resolved 2D photon echo signals. The delocalization of one-exciton states, spatial overlaps between the probability densities of different excitonic states, and their influences on both one- and two-dimensional electronic spectra are studied. The nature of the off-diagonal cross-peaks and the time evolution of both diagonal and off-diagonal peak amplitudes are discussed in detail by comparing experimentally measured and theoretically simulated 2D spectra of the natural Fenna-Matthews-Olson (FMO) photosynthetic light-harvesting complex. We find that there are two noncascading exciton energy relaxation pathways.
本文给出了多发色团体系飞秒二维电子光谱的理论描述。将稳态近似应用于光子回波光谱的计算，并考虑激子弛豫过程，我们得到了用于时间分辨和频率分辨二维光子回波信号数值模拟的解析表达式。研究了单激子态的离域、不同激子态概率密度之间的空间重叠及其对一维和二维电子光谱的影响。通过比较天然芬纳 - 马修斯 - 奥尔森（FMO）光合捕光复合物的实验测量二维光谱和理论模拟二维光谱，详细讨论了非对角交叉峰的性质以及对角峰和非对角峰振幅的时间演化。我们发现存在两条非级联激子能量弛豫途径。
