Infrared Laser Excitation Controlled Reaction Acceleration in the Electronic Ground State.

Abstract

Propelling a ground state reaction by mode-specific vibrational excitation via infrared (IR) light offers a novel route to carry out ground state chemistry. Here, we describe the acceleration of a bimolecular alcoholysis reaction as a paradigm for IR light-driven ground state reactions. Instead of resorting to coherent control, IR light is used for direct or indirect vibrational excitation of the reaction coordinate (RC) overcoming the activation energy and promoting the ground state reaction with negligible heating of the sample. Thus, knowledge of the RC is crucial to pick the reaction accelerating vibrations. Alternatively, upon mapping the reaction accelerating vibrations an image of the RC can be reconstructed. We discuss the concept of RCs and examine strategies to use vibrational energy relaxation pathways to single out vibrations belonging to the RC. The influence of the solvent interaction and limitations due to conformational heterogeneity are considered. We provide an application example generating microstructures of polymers and address the use for chemical synthesis in general.