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Updated: Jul 17, 2026

Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch
Published on: February 7, 2022
Mechanisms of molecular response in the optimal control of photoisomerization
Benjamin Dietzek1, Ben Brüggemann, Torbjörn Pascher
1Department of Chemical Physics, Lund University, PO Box 124, 22100 Lund, Sweden. benjamin.dietzek@chemphys.lu.se
Abstract:
We report on adaptive feedback control of photoinduced barrierless isomerization of 1,1'-diethyl-2,2'-cyanine in solution. We compare the effect of different fitness parameters and show that optimal control of the absolute yield of isomerization (photoisomer concentration versus excitation photons) can be achieved, while the relative isomerization yield (photoisomer concentration versus number of relaxed excited-state molecules) is unaffected by adaptive feedback control. The temporal structure of the optimized excitation pulses allows one to draw clear mechanistic conclusions showing the critical importance of coherent nuclear motion for the control of isomerization.
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