Reversible switching of tetra-tert-butyl-azobenzene on a Au(1Â 1Â 1) surface induced by light and thermal activation

Two-photon photoemission spectroscopy is employed to analyze reversible changes in the electronic structure of the molecular switch tetra-tert-butyl-azobenzene adsorbed on Au(1 1 1) induced by UV-light and thermal activation. The reversible changes are assigned to a trans/cis-isomerization of the molecules in direct contact with the Au(1 1 1) surface.