Darmstadt 2008 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 8: Interaction with intense laser pulses II: Molecules and beyond

A 8.1: Hauptvortrag

Dienstag, 11. März 2008, 14:00–14:30, 3C

Applications of laser aligned molecules — •Henrik Stapelfeldt — Department of Chemistry, University of Aarhus, Denmark

Moderately intense, non-ionizing laser pulses can align molecules along axes fixed in the laboratory [1]. This talk will initially discuss recent results aimed at controlling the 3-dimensional alignment of asymmetric top molecules. In particular, we show how a long laser pulse can strongly confine one axis of a molecule while a second, much shorter pulse, sets the molecule into controlled rotation about the axis arrested. As a result strong 3D alignment occurs immediately after the short pulse and is repeated periodically reflecting the revolution about the axis aligned. Our method opens new directions for field-free 3D alignment and for controlling internal rotations of molecules [2].

Second, we report the first experimental observations of orientationally resolved photoelectron angular distributions using laser aligned molecules [3]. The effect is illustrated by field-free aligned carbon disulfide molecules singly ionized by multiphoton absorption from an intense 800 nm pulse. The experimental results are compared to calculations with the strong field approximation.

[1] H. Stapelfeldt and T. Seideman, Rev. Mod. Phys., 75, 543 (2003). [2] S. S. Viftrup, V. Kumarappan, S. Trippel, H. Stapelfeldt E. Hamilton and T. Seideman, Phys. Rev. Lett., 99, 143602 (2007). [3] V. Kumarappan, et al., to be submitted (2007).