  Electron transfer (ET) at molecule-metal or molecule-semiconductor interfaces
is a fundamental reaction that underlies all electro-chemical and molecular
electronic processes as well as substrate-mediated surface photochemistry. In
this study, we show that ET rates near a metal surface can be significantly
manipulated by periodic modulations of an impurity level of the molecule near a
metal surface. We employ the analytical Marcus theory and two numerical Floquet
surface hopping algorithms that are developed previously, to calculate the ET
rates near metal surface as a function of driving amplitudes and driving
frequencies. We find that ET rates become faster with increasing the driving
amplitude but no turnover effect, while have a turnover effect with increasing
driving frequencies.
