Ultrafast multidimensional dynamics of strong hydrogen bonds - A Cartesianreaction surface approach

The laser driven dynamics of the OH(D) stretching vibration in phthalic aci d monomethylester is investigated. The combination of a 55-dimensional all- Cartesian reaction surface Hamiltonian and the time-dependent self-consiste nt field approach is shown to provide a microscopic picture of intramolecul ar vibrational energy redistribution taking place upon interaction with an external laser field. Choosing suitable zeroth-order vibrational states and combinations thereof a quasi-periodic ia-phase and out-of-phase oscillator y behavior is observed manifesting energy flow on different time scales. Th e fingerprints of this behavior in transient absorption spectroscopy are al so discussed.