N. P. Blanchard

Contributions from surface-modified bulk electronic bands to the reflection anisotropy of Au(110)-(1 × 2)

We investigate the temperature dependence of the optical reflectance anisotropy (RA) of the Au(110)-(1 × 2) surface and find that transitions involving surface-modified bulk bands contribute to the RA spectrum. The RA peaks observed at room temperature at photon energies of 3.52 and 4.50 eV are assigned to the transitions and , respectively. The assignments are based upon a comparison between temperature-induced shifts in the energy of these RAS peaks and thermovariation optical spectroscopy results of the temperature dependence of transition energies between bands at the L symmetry point. The application of RAS to Au(110) can be seen as a model system for exploring surfaces in a range of environments including ultra-high vacuum, high pressures and at the solid/liquid interface. The results reported here further the understanding of the RA spectrum of the clean Au(110) surface.

Pd Deposition onto the Thermally Roughened Cu(110) Surface

We study the deposition of Pd onto two morphologically distinct Cu(110) surfaces: the first being the surface prepared by conventional ion bombardment and anneal cycles and the second being the thermally roughened surface consisting of a well-defined surface morphology of large terraces terminated by exclusively monoatomic height steps. We use the optical technique of reflection anisotropy spectroscopy in combination with scanning tunnelling microscopy to characterise the deposition. We find that the morphological nature of the Cu(110) surface results in a different surface reconstruction for the same conditions of Pd deposition.

SURFACE PREPARATION OF CU(110) FOR AMBIENT ENVIRONMENTS

The preparation of metal surfaces that are smooth and flat over micron lengthscales is desirable for high resolution scanning probe microscopy (SPM) studies ofadsorbed molecules. Standard polishing finishes are often found to exhibit consid-erable roughness and damage including scratches when investigated by SPM. Wehave prepared by means of UHV technology a Cu surface that when in ambient airis considerably smoother than conventional polished surfaces. The RA response inthe region 3.0 – 5.0 eV of this Cu surface can be interpreted in terms of surface–modified bulk bands. Future experiments in our research group will utilise suchsurfaces for studies of biomolecular adsorption.