Charge separation dynamics in nanostructured matter. Contactless measurements of atomic-scale conductance

To avoid 'electrode problems' in conductance measurements of nanostructured matter, a novel contactless method, in which deep inner shell excitation and the following decay processes are utilized, has been devised. The method is applied to Ar clusters, in each of which a Kr atom that absorbs X-ray photons is embedded, and to aromatic molecules, in each of which a Br atom acts as an X-ray absorbing atom. The decay processes are investigated by photoelectron-photoion-coincidence spectroscopy and multi-ion coincidence momentum imaging. The insulating nature of rare-gas clusters and the conductive nature of aromatic molecules are experimentally confirmed. (author)