Oscillatory dephasing is a characteristic of nonMarkovian relaxation when the coherence losses are due to pure dephasing processes. Oscillations in electronic dynamics have also been observed in electron transfer systems. We model a molecular system by a three-level system coupled to a bath of harmonic oscillators. The two excited electronic configurations of the system are coupled by a nonadiabatic interaction V which is treated exactly. An adiabatic picture is given to analyze the influence of V on the relaxation processes in the excited levels at short times. We show that a strong electronic coupling can minimize oscillatory dephasing. (C) 2002 Elsevier Science B.V. All rights reserved.