Cluster‐Controlled Photofragmentation: The Case of the Xe–Pyrrole Cluster

Abstract

In this report we describe a process where chemical control can be used to create a molecular switch. Specifically we demonstrate that the fission of the N-H bond in pyrrole can be “controlled”, i.e., turned ON or OFF, by clustering the system to a single noble gas atom such as Xe. Using slice imaging experiments on the H-atom photofragments in combination with high level quantum mechanical electronic structure calculations, the mechanism underlying the process is unravelled. The effect is general and manifests itself in situations were conical intersections, such as the one present in the pyrrole molecule, a prototype of small DNA bases, are involved in the photochemistry of the system. Hence our observation appears to be a first step towards “biological” control at the molecular level. Part of this work was supported by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, US Department of Energy. Battelle operates the Pacific Northwest National Laboratory for the US Department of Energy.