We present a modified through-bond coupling (MTBC) model for studying charge transfer processes in biological systems.The model connects structural details and electron transfer rate,and thus can reflect the effect of nuclear motions.The proposed model is tested by performing calculations on several hydrocarbon di-radicals,and is found to be in good agreement with experimental data.It is also applied to electron transfer in proteins,and the results shed light on laboratory measurements.The microstructural details of [BPy]+[BF4][?] ionic liquid (IL) were show,using results from quantum chemistry and molecular dynamics calculations.It features apparent short-range order,with cations and anions arranged alternately.