Highly homogeneous, ultrathin films of copper nitride $\left({\mathrm{Cu}}_3\mathrm{N}\right)$ have been grown on Fe(001) at room temperature using a Cu evaporator and a radio-frequency plasma source to obtain atomic nitrogen in a UHV environment. ${\mathrm{Cu}}_3\mathrm{N}$ is a semiconductor with the valence band edge at $-0.65\pm 0.05\mathrm{eV}$ below the Fermi Level. The formation of copper nitride can be detected spectroscopically by the shape of the Cu LVV-Auger electron transition, which changes sensibly in shape and position compared to metallic Cu. ${\mathrm{Cu}}_3\mathrm{N}$ grows epitaxially with the substrate forming flat disklike mosaic blocks, (001) oriented. Both x-ray core level photoelectron spectroscopy and ultraviolet photoelectron spectroscopy photoemission experiments have been used to study the electronic structure. A first-principles calculation has been performed and compared with the measured spectra.

Molecular-dynamics simulations using a Pauling type pairwise potential have been carried out in order to study the structure of the surface of $\gamma -{\mathrm{Al}}_2{\mathrm{O}}_3$. Starting from an ideal (100) face, a reconstruction process occurs in which the unbalanced coordination of surface ions tends to fulfill their coordination capabilities. Oxygen ions come to the surface and pore formation with a concomitant increase of apparent volume takes place. The structure of the surface of the resulting material corresponds to a porous amorphouslike phase in which only short-range order is present. Analysis of the radial distribution function agrees with experimental x-ray-diffraction data.