Unusual reversibility of molecular break-up of PAHs

By combining the high-resolution x-ray photoelectron spectroscopy at the SuperESCA beamline of Elettra with density functional theory a group of scientists from Italy, UK, Denmark and Germany has shown that the process of hydrogen removal from pentacene molecules adsorbed on Ir(111) follows a reversible chemical route, which allows hydrogen re-attachment to the carbon nanoribbon formed after the thermally induced C–H bond break-up. The thermal dissociation taking place upon controlled annealing can be reversed by cooling the system at room temperature and in a hydrogen atmosphere.

Besides the novelty of the chemical process, this phenomenon could have interesting implications for molecular electronics and for the manipulation of graphene nanoribbons which are known to present higher electron/hole mobilities and better thermal transport when dehydrogenated. 

Read more on the Elettra website