High-resolution scanning tunneling microscopy data on the reconstructed Au(111) surface are presented that give a comprehensive picture of the atomic structure, the long-range ordering, and the interaction between reconstruction and surface defects in the reconstructed surface. On the basis of the atomically resolved structure, the stacking-fault-domain model involving periodic transitions from fcc to hcp stacking of top-layer atoms is confirmed. The practically uniform contraction in the surface layer along [11¯0] indicates that the previously proposed soliton functionalisms are not correct descriptions for the fcc→hcp stacking transition. The lateral displacement of ∼0.9 Å in the ${(}_{\mathrm{-}1}^{22}$ ${}_2{}^0{}_{}{}^{}$) unit cell along [112¯] is in good agreement with the transition between fcc and hcp stacking. The vertical displacement in the transition regions (0.20±0.05 Å) is largely independent of the tunneling parameters, while the atomic corrugation (0.2 Å typically, up to 1 Å) depends strongly on tunneling parameters and tip conditions.

The engineering of highly organized systems from instructed molecular building blocks opens up new vistas for the control of matter and the exploration of nanodevice concepts. Recent investigations demonstrate that well-defined surfaces provide versatile platforms for steering and monitoring the assembly of molecular nanoarchitectures in exquisite detail. This review delineates the principles of noncovalent synthesis on metal substrates under ultrahigh vacuum conditions and briefly assesses the pertaining terminology—self-assembly, self-organization, and self-organized growth. It presents exemplary scanning-tunneling-microscopy observations, providing atomistic insight into the self-assembly of organic clusters, chains, and superlattices, and the metal-directed assembly of low-dimensional coordination architectures. This review also describes hierarchic-assembly protocols leading to intricate multilevel order. Molecular architectonic on metal surfaces represents a versatile rationale to realize structurally complex nanosystems with specific shape, composition, and functional properties, which bear promise for technological applications.