The proposed project is an application of the hyperspherical hidden crossing method (HHCM) to positron-atom scattering. Positron-alkali collisions will be investigated in the energy range where there are two open channels, elastic scattering and positronium formation. For positron-hydrogen collisions, the plan is to extend previous two-channel calculations to include excitation to the n=2 states of hydrogen. The objective of this investigation is to provide insight into the dynamics of three charged particles which is basic to the understanding of the dynamics of atomic collisions. The HHCM is well suited for the study of collisions involving three charged particles of arbitrary mass. An important feature that the HHCM method shares with the hyperspherical method is that it treats excitation and the rearrangement process on equal footing. This is important for positronium formation in positron-atom collisions.
