Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 13: Poster 1: Cold Molecules, Femtosecond Spectroscopy, Molecular Dynamics
MO 13.12: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.IV
Ultrafast Circular Dichroism Investigation of the Ring Opening in 7-Dehydrocholesterol — •Julia Meyer-Ilse1,2, Denis Akimov2, and Benjamin Dietzek1,2 — 1Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Jena, Germany — 2Institute of Photonic Technologies (IPHT) Jena e.V., Jena, Germany
UV-femtosecond time-resolved circular dichroism (TRCD) spectroscopy has been used to study the ultrafast changes of chirality in a small molecular biological paradigm sample, 7-dehydrocholeserol (7-DHC). Upon UV-photoexcitation, 7-DHC undergoes a ring opening to produce previtamin D3 and two of the chiral centers of 7-DHC are removed, which impacts the overall chirality of the molecule. Here, measurements of this chirality change connected to the ring opening of 7-DHC with a time-resolution of 280 fs are reported. With this method a previously described discrepancy concerning the photophysics of 7-DHC was clarified. With our set-up the relaxation time of the chirality change was measured to be 1-2 ps, which corresponds to the shortest time-constant in the transient absorption (TA) measurements, allowing us to assign that time-constant to the ring opening.