Paper detail

Is There Elliptic Distortion in the Light Harvesting Complex 2 of Purple Bacteria?

Single molecule spectroscopy (SMS) revealed 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 lineshape, 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 lineshape. 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 lineshape is an intensity weighted average of k=1- and k=0 states.