Selective bond breaking in a molecule with the use of photons opens the way to control chemical reactions. We demonstrate here that dissociation of a molecule can be efficiently achieved by first photoexciting a neighboring atom or molecule. On the example of the giant He-H2 dimer, we show that simultaneous ionization and excitation of the helium atom induces H2 dissociation with a high probability. The excited He+ ion transfers its excess energy via interatomic Coulombic decay (ICD) or electron transfer mediated decay (ETMD) to H2 which is then singly or doubly ionized, respectively. In both cases, the molecular ion dissociates effectively within a few tens of femtoseconds. Molecular-bond breaking induced by ICD and ETMD are expected to be general phenomena, which provide alternatives to standard photochemistry.
Bibliographical noteFunding Information:
This project has received funding from Agence Nationale de la Recherche through Program No. ANR-16-CE29-0016-01. Y.-C.C. thanks the Royal Society for financial support (Grant No. NF171278). N.S. thanks Y. Gu and G. Quinchard for fruitful discussion. J.G. acknowledges financial support from the National Science Foundation of China (Grant No. 21533003). P.K. and P.V. acknowledge financial support from the Czech Science Foundation (Project GAĞR No. 17-10866S).