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MO: Molekülphysik

MO 12: Poster I

MO 12.10: Poster

Dienstag, 23. März 2004, 14:00–16:00, Schellingstr. 3

Molecular orientation via a dynamically induced pulse–train: wave–packet dynamics of NaI in a static electric field — •Philipp Marquetand¹, Arnulf Materny², Niels E. Henriksen³ und Volker Engel¹ — ¹Institut für Physikalische Chemie, Am Hubland, 97074 Würzburg, Germany — ²School of Engineering and Science, International University Bremen, Campus Ring 8, D-28759 Bremen, Germany — ³Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Lyngby, Denmark

We regard the ro–vibrational wave–packet dynamics of NaI molecules in a static electric field after femtosecond excitation to its first electronically excited state. The following quasi–bound nuclear wave–packet motion is accompanied by a bonding situation changing from covalent to ionic. At times when the charge separation is present. i.e. when the bond-length is large, a strong dipole moment exists and rotational excitation takes place. Upon bond contraction, the then covalently bound molecule does not experience the external field. This scenario repeats itself periodically. Thus, the vibrational dynamics causes a situation which is comparable to the interaction of the molecule with a train of pulses where the pulse separation is determined by the vibrational period.