Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 18: Molecular Dynamics
MO 18.6: Vortrag
Donnerstag, 15. März 2012, 15:30–15:45, V38.02
Surface hopping from accurate quantum-classical correspondence — •Sebastian Möbius1, Sebastian Wüster1, Milan Sindelka1, Alexander Eisfeld1,2, and Jan Micheal Rost1 — 1Max Planck Intitute for physics of complex systems, Dresden, Germany — 2Department for Chemistry and Chemical Biology, Harvard University, Boston, USA
Mixed quantum-classical treatments of molecular dynamics are well established to study chemical reaction pathways or collision dynamics. The main idea is to evolve nuclear coordinates on classical trajectories, governed by Newton's equation of motion, and the electronic degrees of freedom fully quantum mechanical by Schroedinger's equation. In contrast to Ehrenfest methods, Tully presented a multi-trajectory surface hopping algorithm, which allows for non-adiabatic transitions between adiabatic eigenstates. This algorithm has been proven successful in various cases, studying collision dynamics. While the traditional derivation of the method arguably gives rise to only part of the non-adiabatic coupling terms in the Born-Oppenheimer separated Schroedinger equation, we present a more sophisticated approach which can reproduce all couplings. Our crucial argument is that only hermitian operators ought to be replaced with a classical variable. We discuss model systems where the newly introduced terms are required in order to match the full quantum calculations. Our extensions of Tully's algorithm opens up new possibilities of application, like spin-orbit coupled systems, atomic Rydberg systems and multidimensional surface intersections (e.g conical intersections).