Embedding at electrode surfaces

Electronic structure calculations are performed on metal surfaces using an embedding method. Firstly, Cu and Ni surfaces with adsorbates are studied. The O/Cu(00T) reconstruction is investigated, and it is found that atomic displacements increase bonding symmetry and is most likely the cause of reconstruction. The interaction between a single graphitic layer and the Ni(III) substrate is also studied, and it is found that interacting states are formed at Ni band gaps. The remainder of the thesis deals with stepson metal surfaces. First, the jelliummodel is used to calculate the work functiondependence on stepdensity. In the low stepdensity limit, the work functionvaries linearly with stepdensity. Further calculations are performed on realistic Pd and Pt surfaces. When electric fields are applied, the screening charge of steppedsurfaces is mostly located at the stepedge. This is explained by the increased fields associated with the edge. Field emission from Pd and Pt surfaces is also studied. It is found that Pd is a better emitter than Pt, owing to work functioneffects. Transmission is dependent on the surface parallel wavevector and decreases with increasing wavevector. The reduced work functionalso plays a role at steppedsurfaces, although the major influence stems from the reduced local work functionat the stepsite. The low effective potential at the stepprovides a locally reduced barrier to electron removal. In addition, an increase in transmission is seen from non-zero wavevectors for steppedsurfaces. The result is that steppedPd and Pt surfaces, with a stepdensity of one stepin every three (001) unit cells, show field emission increased by a factor of four compared with the flat (001) surfaces.