Mainz 2017 – wissenschaftliches Programm

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SYAD: Symposium SAMOP Dissertation-Prize 2017

SYAD 1: SAMOP Dissertation-Prize

SYAD 1.4: Hauptvortrag

Mittwoch, 8. März 2017, 12:30–13:00, RW 1

Circular dichroism and accumulative polarimetry of chiral femtochemistry — •Andreas Steinbacher — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg — Massachusetts Institute of Technology, Department of Chemistry, 77 Mass Ave, Cambridge, MA 02139

Steady-state circular dichroism (CD) or optical activity (OA) are common techniques to analyze chiral samples in the liquid phase. However, the utilized long optical path lengths, high concentrations, and long integration times are not suitable for ultrafast spectroscopy. Hence, only few such approaches are known in literature. In this presentation recently developed ultrafast spectrometers for CD and OA detection are introduced.

For OA probing, a sensitive polarimeter based on heterodyne interferometry and accumulative spectroscopy was developed. With this setup it is possible to detect the OA change accompanying a chirality-modifying photochemical reaction with femtosecond time resolution. Furthermore, one can achieve all-optical discrimination between racemic and achiral molecular solutions.

Furthermore, broadband time-resolved CD spectroscopy based on a setup capable of mirroring an arbitrary polarization state of an ultrashort laser pulse is presented. By passing a broadband probe through this setup it is possible to switch between opposite handedness of the probe on a shot-to-shot basis to detect pump-induced CD changes. To demonstrate the capabilities of this approach the early photochemistry of hemoglobin was investigated.