Energy Transfer in the Light-Harvesting Complexes of Purple Bacteria**Supported by the Research Start-up Foundation for Talents of Northwest A&F University of China under Grant Nos. Z111021106 and Z111021307

Abstract

In this paper, we use a nonlinear decohering quantum model to study the initial step of photosynthesis which is an ultrafast transfer process of absorption the sunlight by light-harvesting complexes and electronic excitation transfer to the reaction center (RC). In this decohering model, the Hamiltonian of the system commutes with the system-environment interaction. We take B850 ring of light-harvesting complex II (LH-II) in purple bacteria as an example to calculate the efficiency of the energy transfer as a function of time. We find that the environmental noise can make the LH-II have stable energy transfer efficiency over a long time. This is to say that the environmental noise which is the decohering source has advantage of the energy transfer in the process of photosynthesis.