  Electron transfer (ET) processes are of broad interest in modern chemistry.
With the advancements of experimental techniques, one may modulate the ET via
such as the light-matter interactions. In this work, we study the ET under a
Floquet modulation occurring in the donor-bridge-acceptor systems, with the
rate kernels projected out from the exact disspaton equation of motion
formalism. This together with the Floquet theorem enables us to investigate the
interplay between the intrinsic non-Markovianity and the driving periodicity.
The observed rate kernel exhibits a Herzberg-Teller-like mechanism induced by
the bridge fluctuation subject to effective modulation.
