We are using the quantum mechanical theories of positron and electron scattering to investigate the geometrical arrangement of atoms at clean surfaces of solids and at surfaces with layers of foreign atoms. Structural information is the first piece of data needed to understand surface phenomena.

Another major area of study is to determine the form of the electron and positron surface barrier potentials experienced by an electron or positron entering or leaving a metal using low energy scattering techniques. Details of this potential including the position of the image-potential tail and its saturation near the surface atoms is needed by other workers to verify many-body theories of surface interactions and to predict positronium formation rates and positron annihilation characteristics at surfaces and voids.

The complete understanding of surface phenomena at the atomic level requires a detailed knowledge of the energy states of the electrons in the potential at the surface. We have developed a technique to calculate the band structure of surface electron states and resonances which are localised beyond the first atomic layer of metal surfaces. These results can be compared with experimental photoemission and inverse photoemission data and this provides another method for determining surface properties.

• Realistic calculation of image surface states and resonances for comparison with experiment. M.N. Read and A.S. Christopoulos, Phys. Rev., B45, 13729 (1992).
• Surface barrier states and resonances of metals. M.N. Read and A.S. Christopoulos, Springer Proceedings in Physics, 73, 116 (1993).

School of Physics
The University of New South Wales
SYDNEY 2052
Australia

M.Read@unsw.edu.au

61 2 9385 5241

61 2 9385 6060