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Updated: Nov 5, 2025

Novel Techniques for Observing Structural Dynamics of Photoresponsive Liquid Crystals
Published on: May 29, 2018
Electronic and Geometric Characterization of TICT Formation in Hemithioindigo Photoswitches by Picosecond Infrared
Klara Stallhofer1, Matthias Nuber1, Franziska Schüppel2
1Physik-Department, Lehrstuhl für Laser- und Röntgenphysik, Technische Universität München, James-Franck-Str. 1, 85748 Garching, Germany.
Abstract:
Deciphering the exact electronic and geometric changes of photoexcited molecules is an important task not only to understand the fundamental atomistic mechanisms but also to rationally design molecular properties and functions. Here, we present a combined experimental and theoretical study of the twisted intramolecular charge transfer (TICT) process in hemithioindigo photoswitches. Using ultrafast transient IR spectroscopy as the main analytical method, a detailed understanding of the extent and direction of charge transfer within the excited molecule is obtained. At the same time, the geometrical distortion is monitored directly via changes of indicative vibrational modes over the time course of the photoreaction. These high-resolution data deliver a detailed molecular movie of the TICT process in this important class of chromophores with picosecond time resolution.
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