Regensburg 2000 – scientific programme

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DY: Dynamik und Statistische Physik

DY 25: Symposium Niveaustatistik und Quantenchaos

DY 25.8: Invited Talk

Tuesday, March 28, 2000, 17:30–18:00, H3

Nonadiabatic Processes in Quantum-Classical Molecular Dynamics — •Christof Schuette, Peter Nettesheim, and Burkhard Schmidt — Konrad-Zuse-Zentrum, Takustr.7, 14195 Berlin

In molecular dynamics applications there is a growing interest in mixed quantum-classical models. The quantum-classical Liouville equation (QCL) describes most atoms of the molecular system under consideration by means of a classical phase space density but an important, small portion of the system by means of quantum mechanics. In the first part of the talk, the QCL will be derived from the full quantum dynamical (QD) description by applying the Wigner transform to the “classical part” of the system only. We will discuss the conditions under which the QCL model approximates the full QD evolution of the system. The second part will show that this approach allows a rigorous derivation of so-called surface-hopping techniques as stochastic discretizations of the QCL. This will permit us to discuss the approximation error of surface hopping algorithms theoretically and to illustrate our insights via numerical experiments for certain nonadiabatic quantum systems.