Department of Chemistry and Biochemistry, Queens College of the City University of New York, Flushing, New York 11367-1597, United States.
J Phys Chem B. 2011 Nov 10;115(44):12947-53. doi: 10.1021/jp202344s. Epub 2011 Oct 17.
Single molecule spectroscopy (SMS) revealed an unusually large Gap between two major exciton peaks of the B850 unit of light harvesting complex 2 (LH2), which could be explained assuming elliptic distortion or k = 2 symmetry modulation in the site excitation energy. On the basis of extensive simulation of the SMS data and ensemble line shape, we found that uniform modulation of k = 2 symmetry cannot explain the dependence of intensity ratios on the Gap of the two major peaks, which are available from SMS, nor the ensemble line shape. Alternative models of disorder with k = 1 and k = 2 symmetry correlation are shown to reproduce these data reasonably well and can even explain the Gap distribution when it is assumed that the lower major peak in the SMS line shape is an intensity weighted average of k = 1- and k = 0 states.
单分子光谱（SMS）揭示了光捕获复合物 2（LH2）的 B850 单元中两个主要激子峰之间异常大的间隙，可以通过假设在激发能中的椭圆变形或 k=2 对称调制来解释。基于对 SMS 数据和整体线形状的广泛模拟，我们发现，k=2 对称的均匀调制不能解释SMS 可获得的两个主要峰强度比与间隙之间的依赖关系，也不能解释整体线形状。具有 k=1 和 k=2 对称相关的无序替代模型被证明可以很好地再现这些数据，甚至可以解释当假设 SMS 线形状中的较低主要峰是 k=1 和 k=0 态的强度加权平均值时的间隙分布。
