Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 11: Theory: Structure and Dynamics

MO 11.5: Vortrag

Donnerstag, 5. April 2001, 16:45–17:00, H107

Ultrafast quantum dynamics: Passive control via conical intersections — •Angelika Hofmann and Regina de Vivie-Riedle — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching

Many ultrafast reactions proceed via conical intersections of different electronic potential energy surfaces (PES). As a prototype system we investigate the photoinduced ringopening of cyclohexadiene. We have introduced reactive coordinates to reduce this high-dimensional problem and computed the corresponding interpolated ab initio PES.
The dynamics is monitored by means of wavepacket propagation revealing that the wavefunction branches already in the excited state. Hence the return to the groundstate surface proceeds via two different conical intersections [1]. The branching ratio can be influenced by the initial wavepacket preparation thereby allowing the passive control of the outcome.
Recently we have calculated the non-adiabatic coupling elements in the vicinity of both conical intersections. Incorporating them into the wavepacket dynamics allows us to study the whole relaxation process and to investigate the effect of the branching in the excited state on the product yield.
[1] A. Hofmann and R. de Vivie-Riedle, J. Chem. Phys. 112, 5054 (2000)