Frankfurt 2006 – scientific programme

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MO: Molekülphysik

MO 23: Photochemistry

MO 23.8: Talk

Tuesday, March 14, 2006, 15:45–16:00, H12

System and environment influences on controlled ultrafast dynamics — •Judith Voll, Dorothee Geppert, and Regina de Vivie-Riedle — LMU Department Chemie, Butenandtstr.11, 81377

In our group a model system for molecular switches was developed. The degrees of freedom of the active center were reduced to relevant reactive coordinates on the essential timescale. Highly accurate quantum chemical calculations lead to two dimensional electronic potential energy surfaces with conical intersections enabling a coupling between them. On these potential surfaces exact ultrafast quantum dynamics on the femtosecond timescale is performed following laser excitation. Optimal Control Theory made it possible to control the reaction by applying optimized differently shaped laser pulses [1]. Diverse modifications of the reduced model lead to a more realistic behaviour of the system. We augmented the single conical intersections to a seam of conical intersections and examined different barriers on the excited state. These could be induced by mixing with higher electronic states, additional steric groups or solvent effects. In first attempts to understand the influence of the solvents motion on our systems dynamics we use potential surfaces oscillating in time. ∖Zitat{1}{D. Geppert, L. Seyfarth and R. de Vivie-Riedle, App. Phys. B, 79 (2004) 987-992}