Infrared Laser control of molecular reaction dynamics in the electronic ground state. Theory and experiment

• Applicants: Professor Dr. Karsten Heyne; Professor Dr. Oliver Kühn
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Analytical Chemistry ; Experimental Condensed Matter Physics
• Term: from 2010 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 169703910

• Final Report Year: 2024

Final Report Abstract

The aim of the project was to accelerate the synthesis reaction between two molecules in the ground state using IR excitation and to investigate this new process in detail for the first time. As we were the first to successfully carry out this experiment, a number of fundamental questions arose that needed to be addressed in close cooperation between experiment and theory. A key question was the possible identification of the reaction coordinate and the interplay of inter- and intramolecular vibrational redistribution with the molecular reaction mechanism. As part of the project, we were able to demonstrate that it is possible to accelerate the ground state reaction using fs mid-IR excitation. We were able to demonstrate reaction acceleration after excitation of the OH and OD stretching vibrations in cyclohexanol (CH-ol) and were also able to show that excitation of the NCO stretching vibration of phenyl isocyanate (PHI) does not lead to reaction acceleration. This was also the case for altered mixing ratios of CH-ol to PHI (4:1 instead of 1:1). Furthermore, we were able to track vibrational relaxation in PHI from 10 to 20 ps after excitation of the NCO stretching vibration. By using improved detection, we were able to observe instantaneous signals in the product region after excitation of the OD stretching vibration. This could be interpreted as the OD stretching vibration of CH-ol being part of the reaction coordinate. The delayed increase of the reaction product in the 10-20 ps range could be due to a distribution of different starting configurations. A more detailed theoretical analysis of possible reaction configurations led to the conclusion that those configurations leading to a reaction are only relatively rarely adopted, which explains the low experimental yield. The theoretical part of the project also investigated the potential of the Direct Optical Control method for laser control of vibrational dynamics, which has so far only been used in engineering. It was shown that the method has a number of advantages over the conventional indirect approach due to its flexibility.

Publications

• Acceleration of a ground-state reaction by selective femtosecond-infrared-laser-pulse excitation. Nature Chemistry, 10(2), 126-131.
  Stensitzki, Till; Yang, Yang; Kozich, Valeri; Ahmed, Ashour A.; Kössl, Florian; Kühn, Oliver & Heyne, Karsten
  
• Infrared Laser Excitation Controlled Reaction Acceleration in the Electronic Ground State. Journal of the American Chemical Society, 141(30), 11730-11738.
  Heyne, Karsten & Kühn, Oliver
  
• Three-dimensional view of ultrafast dynamics in photoexcited bacteriorhodopsin. Nature Communications, 10(1).
  Nass Kovacs, Gabriela; Colletier, Jacques-Philippe; Grünbein, Marie Luise; Yang, Yang; Stensitzki, Till; Batyuk, Alexander; Carbajo, Sergio; Doak, R. Bruce; Ehrenberg, David; Foucar, Lutz; Gasper, Raphael; Gorel, Alexander; Hilpert, Mario; Kloos, Marco; Koglin, Jason E.; Reinstein, Jochen; Roome, Christopher M.; Schlesinger, Ramona; Seaberg, Matthew; ... & Schlichting, Ilme
  
• Ultrafast Backbone Protonation in Channelrhodopsin-1 Captured by Polarization Resolved Fs Vis-pump—IR-Probe Spectroscopy and Computational Methods. Molecules, 25(4), 848.
  Stensitzki, Till; Adam, Suliman; Schlesinger, Ramona; Schapiro, Igor & Heyne, Karsten
  
• Direct Optimal Control Approach to Laser-Driven Quantum Particle Dynamics. Frontiers in Physics, 9(2021, 4, 23).
  Ramos Ramos, A. R. & Kühn, O.
  
• Ultrafast Electron Transfer in a Self-Assembling Sulfonated Aluminum Corrole–Methylviologen Complex. The Journal of Physical Chemistry B, 125(37), 10571-10577.
  Zahn, Clark; Stensitzki, Till; Berg, Alexander; Mahammed, Atif; Zacarias, Angelica; Gross, Zeev & Heyne, Karsten
  
• Manipulating the dynamics of a Fermi resonance with light. A direct optimal control theory approach. Chemical Physics, 555(2022, 3), 111431.
  Ramos Ramos, Alejandro R. & Kühn, Oliver
  
• Ultrafast proton-coupled isomerization in the phototransformation of phytochrome. Nature Chemistry, 14(7), 823-830.
  Yang, Yang; Stensitzki, Till; Sauthof, Luisa; Schmidt, Andrea; Piwowarski, Patrick; Velazquez Escobar, Francisco; Michael, Norbert; Nguyen, Anh Duc; Szczepek, Michal; Brünig, Florian Nikolas; Netz, Roland Rüdiger; Mroginski, Maria Andrea; Adam, Suliman; Bartl, Franz; Schapiro, Igor; Hildebrandt, Peter; Scheerer, Patrick & Heyne, Karsten
  
• Ultrafast protein response in the Pfr state of Cph1 phytochrome. Photochemical & Photobiological Sciences, 22(4), 919–930.
  Yang, Yang; Stensitzki, Till; Lang, Christina; Hughes, Jon; Mroginski, Maria Andrea & Heyne, Karsten
  
• Shaping the Laser Control Land scape of a Hydrogen Transfer Reaction by Vibrational Strong Coupling. A Direct Optimal Control Approach, J. Chem. Phys. 160, xxx (2024)
  Ramos, A.R.R.; Fischer, E.; Saalfrank, P. & Kühn, O.