We trace vibrational wavepacket motion in two-dimensional electronic spectra of a two-level electronic system. The vibronic evolution induces a periodic beating pattern of the diagonal-to-antidiagonal peak width ratio in the absorptive signal part and a periodic tilt of the nodal line in the dispersive signal part.
These modulations can assigned to periodic modulations of the relative amplitudes of rephasing and non-rephasing contributions to the signal.