Localization and coherent dynamics of excitons in the two-dimensional optical spectrum of molecular J-aggregates
Localization and coherent dynamics of excitons in the two-dimensional optical spectrum of molecular J-aggregates
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DOI：
10.1063/1.2897753
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发表时间：
2008-04-28
影响因子：
4.4
通讯作者：
Knoester, Jasper
中科院分区：
文献类型：
--
作者：
Dijkstra, Arend G.;Jansen, Thomas La Cour;Knoester, Jasper
低温下 J 聚集体的二维光谱提供了隐藏在传统宽带泵浦探针光谱中的有关激子态性质和动力学的大量信息。通过数值模拟，我们研究了二维吸收光谱，发现它以V形负峰和蓝移椭圆形正峰为主。我们演示了一种简单的方法，可以根据零等待时间实验中这两个特征之间的距离得出激子局域化尺寸的能量依赖性。当等待时间打开时，V 峰充满了由于群体松弛而产生的额外正峰。从该峰的时间演变，可以获得能量相关的弛豫率。对二维光谱的相干贡献的振荡不会被非均匀机制减弱，并且可以清晰地看到。 (C) 2008 年美国物理研究所。
Two-dimensional optical spectra of J-aggregates at low temperature provide a large amount of information about the nature and dynamics of exciton states that is hidden in conventional broad band pump-probe spectra. By using numerical simulations, we study the two-dimensional absorption spectrum and find that it is dominated by a V-shaped negative peak and a blueshifted elliptic positive peak. We demonstrate a simple method to derive the energy dependence of the exciton localization size from the distance between these two features in the zero waiting time experiment. When the waiting time is turned on, the V peak is filled with an extra positive peak resulting from population relaxation. From the time evolution of this peak, energy dependent relaxation rates can be obtained. The oscillations of coherent contributions to the two-dimensional spectrum are not damped by inhomogeneous mechanisms and can be seen clearly. (C) 2008 American Institute of Physics.