Heidelberg 2015 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 9: Femtosecond Spectroscopy 2

MO 9.1: Hauptvortrag

Dienstag, 24. März 2015, 14:30–15:00, PH/HS1

Control and Spectroscopy of Chiral Systems in the Condensed Phase — •Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

Chirality is a fundamental structural property arising from symmetry considerations: A chiral object cannot be superimposed with its mirror image. In this presentation, progress will be shown toward chirally selective control and time-resolved chiral spectroscopy of molecules in the condensed phase. For this purpose, a variety of fundamental and practical issues have to be addressed. Solutions to some of the problems will be discussed. As a means to introduce chirality via light in the most flexible fashion, we have developed vector-field shaping with independent ultrafast control over amplitude, phase, and polarization of an ultrashort pulse as a function of time. Another necessary ingredient is a detection method that provides chiral sensitivity. We have constructed a highly sensitive polarimeter and used it together with accumulative spectroscopy to measure the optical rotation change upon a chirality-modifying photochemical reaction. Thus we achieved all-optical discrimination between racemic and achiral molecular solutions. A second option for chiral detection is to measure photoinduced changes in circular dichroism (CD). Using a new setup for creating “light-pulse enantiomers”, we have developed broadband time-resolved CD spectroscopy with shot-to-shot white-light detection. As an example, we investigated oxygen release in hemoglobin.