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Nonadiabatic solvation dynamics and decoherence: a molecular hydrodynamic approach

Presenter
March 5, 2009
Abstract
We present a recently developed mixed quantum-classical method which accounts for the evolution of a quantum subsystem coupled to a non-equilibrium environment (solvent) described in an extended hydrodynamic setting [1]. Starting from a hybrid quantum-classical phase-space distribution, coupled equations for the quantum-classical local density and momentum density are derived which feature the characteristic population-coherence coupling of the nonadiabatic quantum evolution. A generalized free energy functional is introduced, which is similar to the functionals used in dynamical density functional theory (DDFT) methods [2] but is adapted to the quantum-classical setting. The relevant functionals involve two-particle (or, more generally, n-particle) correlation functions that are constructed from state-specific microscopic solute-solvent interactions. A microscopic Marcus-type functional for polar solvation is considered as a special case. The present formulation is particularly appropriate to describe ultrafast solvation dynamics coupled with charge transfer, for example in photochemical charge transfer processes. By the explicit consideration of quantum coherence, the details of population transfer and its susceptibility to decoherence effects, become amenable to direct investigation. First numerical examples are presented [3] and the extension of the formalism beyond the free energy functional formulation are addressed, in particular in view of including non-equilibrium solvent correlations. [1] I. Burghardt and B. Bagchi, Chem. Phys. 329, 343 (2006). [2] B. Bagchi and A. Chandra, Adv. Chem. Phys. LXXX, 1 (1991); U. Marini Bettolo Marconi and P. Tarazona, J. Chem. Phys. 110, 8032 (1999); A. J. Archer and R. Evans, J. Chem. Phys. 121, 4246 (2004). [3] P. Ramanathan, S. Parry, S.-L. Zhao, K. H. Hughes, and I. Burghardt, to be submitted.