Abstract
To lowest order in the electron-phonon coupling causing electron transitions among electronic eigenstates, the extent (on the time axis) of the memory functions wrs(t) governing the state population via the generalized master equations for the diagonal elements of the electron density matrix ρ(t) is independent of the coupling, being given by the decay time of the bath correlation functions. However, a typical reciprocal decay time of some higher-order contributions to wrs(t) has been found to be given by the reciprocal decay time of the off-diagonal elements of ρ(t), i.e. to be proportional to the square of the electron-phonon coupling constant. This feature makes such weakly damped contributions non-negligible even in lowest-order dynamics, as is illustrated on a dimer.