Probing and locally modifying the intrinsic electronic structure and the conformation of supported nonplanar molecules

The supramolecular self-assembly of rubrene (C₄₂H₂₈) on Au(111) results in different adsorption conformations of the physisorbed molecules. Owing to the three-dimensional geometry of the molecule providing an inherent decoupling of the molecular π states from the substrate, the conformers are distinguished by their submolecular appearance in the scanning tunneling microscopy images and by the corresponding position of the highest occupied molecular orbital in the differential conductance $(dI∕dV)$ spectra. The application of an electric field induces a switching of the electronic and geometric conformation of the self-assembled molecules.