Allan D. Stauffer Ph.D. (London) Professor Emeritus of Physics This e-mail address is being protected from spambots. You need JavaScript enabled to view it Research Field: Atomic, Molecular and Optical Physics Research specialization: Atomic and molecular physics. Publications

I am primarily interested in the scattering of electrons and positrons from atoms. Collaborating with graduate students and international co-workers, we perform large scale numerical computations of these processes and develop theoretical and numerical methods to carry them out.

For electron scattering problems, we have been concentrating on atomic targets with large nuclear charge. In order to take into account the fine structure of the atom and the spin polarization of the scattered electrons, our calculations are based on the Dirac equations and a fully relativistic treatment of the system. We have developed the very successful Relativistic Distorted-Wave Method for evaluating the various collision parameters. We calculate the usual scattering cross sections as well as the spin polarization parameters for the scattered electrons and the Stokes parameters for the light emitted from atoms excited during the scattering interaction. We have close connections with various experimental groups and our choice of research problems is guided by the present state of experimental investigation.

In the case of positron scattering from atoms, the experimental side is much less well developed than for electrons. Thus we concentrate on amassing sufficient data to be able to compare with the less detailed measurements that are available. These consist of total cross sections, excitaion and ionization cross sections and parameters that are peculiar to positron scattering such as annihilation cross sections.

I am also involved in projects which make use of the atomic data we generate. A large scale Monte Carlo simulation of gas-filled x-ray detectors is one example where large amounts of data of varying degrees of accuracy are required. This data must be acquired by a variety of means since no one method will be applicable over the large range of energies required.