The dynamics of molecular vibrational dephasing (IVR) are governed by the coupling structure of the vibrational Hamiltonian. We use a recently developed factorization model for normal coordinate potentials to compare the importance of direct high order couplings to both direct low order couplings and low-order coupling chains. The importance of high order couplings is characterized as a function of the vibrational energy and of molecular size. Particular attention is paid to phase cancellation effects in coupling chains, and to correlations between vibrational modes depending on their localization length. To account properly for IVR at high densities of states and long times, high order couplings must be taken into account.

Articles you may be interested inCorrelated ab initio investigations on the intermolecular and intramolecular potential energy surfaces in the ground electronic state of the O 2 − ( X Π g 2 ) − HF ( X Σ + 1 ) complex

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Scaling models for the polyatomic potential energy surface occupy a ground intermediate between ab initio surfaces and random matrix models. They are useful for the study of vibrational energy redistribution (IVR) in large molecules, and have been shown to reproduce many features of more accurate spectroscopically fitted or