Horenko, I. and Schmidt, B. and Schütte, Ch. (2001) A Theoretical Model for Molecules Interacting with Intense Laser Pulses: The Floquetbased QuantumClassical Liouville Equation. J. Chem. Phys., 115 (13). pp. 57335743.

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Official URL: http://dx.doi.org/10.1063/1.1398577
Abstract
The Floquetbased quantumclassical Liouville equation (FQCLE) is presented as a novel theoretical model for the interaction of molecules with intense laser pulses. This equation efficiently combines the following two approaches: A small but spectroscopically relevant part of the molecule is treated quantummechanically while the remaining degrees of freedom are modelled by means of classical molecular dynamics. The corresponding nonadiabatic dynamics is given by the quantumclassical Liouville equation which is a firstorder approximation to the partial Wigner transform of full quantum dynamics. The dynamics of the quantum subsystem is described in terms of instantaneous Floquet states thus eliminating highly oscillatory terms from the equations of motion. The resulting FQCLE is shown to have a well defined adiabatic limit: For infinitely heavy classical particles and for infinitely slow modulation the dynamics adiabatically follows the Floquet quasienergy surfaces for a strictly timeperiodic field. Otherwise, nonadiabatic effects arise both from the motion of the classical particles and from the modulation of the field which is assumed to be much slower than the carrier frequency. A numerical scheme to solve the FQCLE is based on a Trotter splitting of the time evolution. The simplest implementation can be realized by an ensemble of trajectories stochastically hopping between different Floquet surfaces. As a first application we demonstrate the excellent agreement of quantumclassical and fully quantummechanical dynamics for a twostate model of photodissociation of molecular fluorine. In summary, due to the favorable scaling of the numerical effort the FQCLE provides an efficient tool for the simulation of medium to large molecules interacting with intense fields beyond the perturbative regime.
Item Type:  Article 

Subjects:  Mathematical and Computer Sciences > Mathematics 
Divisions:  Department of Mathematics and Computer Science > Institute of Mathematics Department of Mathematics and Computer Science > Institute of Mathematics > BioComputing Group 
ID Code:  79 
Deposited By:  Admin Administrator 
Deposited On:  03 Jan 2009 20:20 
Last Modified:  03 Mar 2017 14:39 
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