Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 57: Poster: Quantum Control

MO 57.1: Poster

Thursday, March 22, 2007, 16:30–18:30, Poster A

Quantum dynamical simulations and control of light-induced molecular torsion — •Steffen Belz¹, Omar Deeb², Shireen Alfalah², and Monika Leibscher¹ — ¹Institut für Chemie und Biochemie, Freie Universität Berlin, Germany — ²Department of Chemistry and Chemical Technology, Al-Quds University, Jerusalem, Palestinian Authority

Photochemical isomerization reactions or molecular torsion as occurring e.g. in the process of vision are currently attaining increasing interest. These light induced isomerizations which usually proceed within very short time-scales of several hundred femtoseconds [1] are governed by conical intersections between different electronic states.

In this study, we investigate molecular torsion for model systems like fulvene by means of quantum dynamical simulations. Moreover, we present the transformation of the adiabatic potential energy surfaces obtained by quantum chemical ab initio calculations into a so called diabatic representation [2,3] and point out how the pathway of the photochemical reaction depends on the structure of the conical intersection. Another aim of our study is the control of the outcome of isomerization reactions by specially designed femtosecond laser pulses. Here we show how series of two UV-laser pulses can be applied in order to increase the efficiency of the cis-trans isomerization.

[1] J.E. Kim, D. W. McCamant, L. Zhu, R.A. Mathies, J. Phys. Chem. B 105, 1240 [2001].

[2] A. Thiel, H. Köppel, J. of Chem. Phys. 110, 9371 [1999].

[3] M. Baer, R. Englmann, Mol. Phys. 75, 293 [1992].