Simulation of the Two-Dimensional Electronic Spectroscopy and Energy Transfer Dynamics of Light-Harvesting Complex II at Ambient Temperature

We simulate the two-dimensional electronic spectra (2DES) of the light-harvesting complex II (LHCII) at room temperature by combining the hierarchical equations of motion method and the equation-of-motion phase-matching approach. The laser-excited population dynamics of LHCII is also calculated to help understanding the 2DES. Three different excitation schemes are studied, including (1) only the chlorophyll (Chl) b Q(y), states of LHCII are excited, (2) only the Chl a Q(y )states are excited, and (3) both the Chl b and Chl a states are excited. The energy transfer pathways and time scales revealed from the 2DES in schemes (1) and (2) agree with the recent experimental studies for the Chl b to Chl a energy transfer and the excitation energy relaxation process within the CM a manifold. We also propose a different way to better present the signals of bottleneck states by investigating the diagonal peaks of the 2DES in scheme (3).