<i>Ab Initio</i> Potentials for Low-Energy Positronium Scattering

This poster presents ab initio potentials for positronium-atom and positronium-molecule interactions. Two methods are used to calculate the potential energy: self-consistent solution of the Hartree-Fock equations and solution of the Kohn-Sham equations at the level of the local density approximation. The total energy is computed for a wide range of positronium-molecule separations, molecular orientations, and basis sets. Comparing the two methods illustrates the importance of both electron-electron and electron-positron correlations in obtaining realistic potentials.

Low-energy positronium scattering may soon become experimentally feasible in facilities such as the positronium beam line at the University College in London. This goal of this study is to provide a starting point for the theoretical analysis of positronium scattering at low energies from first principles, to complement existing studies based on semi-empirical potentials.