We present numerical studies of femtosecond time-resolved probes of coupled wave packet dynamics in model polyatomic systems. Of specific interest is the possibility of using the structure and symmetry of the final states accessed by the probe field to discern vibrational energy flow. Simple wave packets can often exhibit classical localization, thus facilitating a mechanistic, trajectory-like picture of the quantum dynamics. This feature, however, does not necessarily survive in complex multidimensional problems due to differing quantum mechanical dephasing rates in different degrees of freedom. To recover a classical-like picture of energy flow between coupled vibrational modes, we introduce a final-state-resolved measure of wave packet dynamics, a low-frequency band-pass filter of the signal, which is specifically sensitive to intermode energy flow.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry