Frankfurt 2006 – scientific programme

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MO: Molekülphysik

MO 26: Poster: Photochemistry

MO 26.2: Poster

Tuesday, March 14, 2006, 16:30–18:30, Labsaal

Trapping and cooling of molecular ions:
Towards ultrafast imaging of single molecule structural changes — •Steffen Kahra and Tobias Schätz — Max-Planck-Institut für Quantenoptik, Garching

Knowledge about the spacial structure of bio-molecules is a vital prerequisite for a detailed understanding of their functional behaviour in natural environment. In some cases photoexcitation followed by rapid internal structural reorganization of the molecule establishes the basis for ultrafast processes in biology. So far – besides indirect spectroscopic methods dependent on models based on certain theoretic assumptions – there is no technique available to follow these structural changes on the required femtosecond timescale. We propose an experimental scheme using molecular ions in a Paul-trap. Having them sympathetically cooled by ancilla Mg⁺-ions and aligned by short fs-laser pulses we could benefit from very recent progress in development of short and intense laser sources. They allow the generation of single electron pulses with few fs time resolution. These electrons will be diffracted by the charge density of the isolated molecular ion and thereby leave a measurable signature of its instantaneous structure. For the first time it would be possible to directly observe molecular restructuring by time resolved single electron diffraction on aligned single molecular ions.