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SYFM: Symposium Quantenkontrolle funktionaler Moleküle

SYFM 2: Quantum control of functional molecules II

SYFM 2.4: Hauptvortrag

Mittwoch, 21. März 2007, 18:00–18:30, 6C

Quantum control of electric ring currents by circularly polarized laser pulses — •Jörn Manz and Ingo Barth — Freie Universität Berlin, Institut für Chemie und Biochemie, Takustr. 3, 14195 Berlin

Few cycle laser pulses with durations from several hundred as to few fs may induce electronic excitations of valence electrons in oriented molecules, atoms, or ions. In particular, circularly polarized laser pulses may induce electron circulation or electric ring currents and induced magnetic fields in ring-shaped molecules such as Mg-porhpyrin, around linear molecules such as AlCl, or atoms. These ring currents are more than hundred times stronger than traditional ones induced by permanent magnetic fields. Moreover, the laser pulses allow active control, i.e. they may serve as "traffic light" for electronic pathways along alternative molecular bonds in ring-shaped molecules. Furthermore, analytic expressions derived for the non-relativistic H-atom and for one-electron ions show that electrons in 2p₊ or 2p₋ atomic orbitals have the strongest electric ring currents and the strongest magnetic fields. The LCAO-MO method can be applied in order to estimate approximate values of the ring currents and induced magnetic fields in molecules, based on the analytical formulas for atomic orbitals.

Financial support by Deutsche Forschungsgemeinschaft (project Ma 515/23-1), Fonds der chemischen Industrie and Bundesagentur für Arbeit is gratefully acknowledged.