Nucleation, formation, and stability of benzene islands on Cu{111}

We have imaged stable islands of benzene molecules on the surface of Cu{111} at 77 K using a low temperature ultrahigh vacuum scanning tunneling microscope. The islands consist of a small number of benzene molecules and nucleate in straight lines on the Cu{111} surface. The ordering and stability of these clusters are discussed in terms of the molecular interactions with the substrate surface state electrons and intermolecular interactions.