Pisliakov Andrei V, Mancal Tomás, Fleming Graham R
Department of Chemistry, University of California-Berkeley, Berkeley, CA 94720, USA.
J Chem Phys. 2006 Jun 21;124(23):234505. doi: 10.1063/1.2200705.
Using the nonperturbative approach to the calculation of nonlinear optical spectra developed in a foregoing paper [Mancal et al., J. Chem. Phys. 124, 234504 (2006), preceding paper], calculations of two-dimensional electronic spectra of an excitonically coupled dimer model system are presented. The dissipative exciton transfer dynamics is treated within the Redfield theory and energetic disorder within the molecular ensemble is taken into account. The manner in which the two-dimensional spectra reveal electronic couplings in the aggregate system and the evolution of the spectra in time is studied in detail. Changes in the intensity and shape of the peaks in the two-dimensional relaxation spectra are related to the coherent and dissipative dynamics of the system. It is shown that coherent electronic motion, an electronic analog of a vibrational wave packet, can manifest itself in two-dimensional optical spectra of molecular aggregate systems as a periodic modulation of both the diagonal and off-diagonal peaks.
利用前文[Mancal等人，《化学物理杂志》124, 234504 (2006)，前文]中开发的用于计算非线性光学光谱的非微扰方法，给出了激子耦合二聚体模型系统的二维电子光谱计算结果。在雷德菲尔德理论框架内处理耗散激子转移动力学，并考虑分子系综中的能量无序。详细研究了二维光谱揭示聚集系统中电子耦合的方式以及光谱随时间的演化。二维弛豫光谱中峰强度和形状的变化与系统的相干和耗散动力学相关。结果表明，相干电子运动（振动波包的电子类似物）在分子聚集系统的二维光谱中可表现为对角峰和非对角峰的周期性调制。
