We calculate pump-probe signals obtained from femtosecond excitation of I-2 molecules. It is shown that, depending on the parameters of the pump laser-pulse, the signals can exhibit a regular oscillatory behavior although the vibrational wave packet which is produced in the pump process, is delocalized over the entire classically allowed region. The respective structures can be related to temporal variations of an enhanced probability density which, in turn, are related to the underlying classical motion. We further demonstrate that the use of time-resolved photoelectron spectroscopy allows for a characterization of the structures which appear in the time-dependent wave function.