Adsorption of L-lysine (or, in absolute nomenclature, S-lysine) on Cu(001) has been studied with a UHV-STM. The binding energy is estimated to be not lower than 1.6 eV, and thus lysine is expected to be in its anionic form on the surface. The adsorbates have two phases, that is, the two-dimensional (2D) gas and solid phases. We speculate that in the 2D gas phase the molecules stand upright on the surface with their two oxygen atoms at the atop sites and can diffuse frequently, and that in the 2D solid phase the molecules lie down on the surface and connect to their neighboring molecules by hydrogen bonds so to form two slightly different superstructures, Cu(001)( -2 4 41 )-and Cu(001)( -3 4 41 )-L-lysine, for which models have been proposed for further investigation. Surprisingly, adsorption of L-lysine can make all steps restructuring into {3 1 17} facets with the same chirality. This phenomenon shows that chiral metal surfaces have potential in discrimination of molecular chirality.

Adsorption and self-assembly of glycine on the Cu(111) surface are studied by means of scanning tunneling microscopy in an ultrahigh vacuum environment. The results show that the adsorbates are chemisorbed on the surface, may take three different conformations, and can form the 2-D gas phase, the chain phase, and two superstructures (2-D solid phases). Although the chain phase was reported as seen from several other amino acid/Cu(001) systems, a concrete model of it is proposed here for the first time. Besides, detailed models have also been proposed for the two superstructures, for further investigation. Combining the results of the present glycine/Cu(111) system with those obtained previously for the glycine/Cu(110) and -(001) systems, a coherent picture of the behavior of glycine molecules adsorbed on Cu surfaces emerges and is discussed.