Seminar
Time:
Collisions of Positronium with Atoms and Molecules
Date:
3:00 pm
Jorgensen Hall Room: 145
Speaker: Robyn S. Wilde, Oregon Institute of Technology
Experimental measurements of the total scattering cross section of Positronium (Ps) from various atomic and molecular targets are very similar to electron scattering cross sections above the Ps ionization threshold. This phenomenon has been explained theoretically using the impulse approximation. Below the ionization threshold the impulse approximation breaks down, and pseudopotential calculations have given good results for rare gas atoms. We apply the impulse approximation and the pseudopotential method to elastic scattering of Ps by H2 by assuming that H2 is spherically symmetric. We have supplemented the elastic cross sections by calculation of the Ps ionization cross section using a binary encounter approach. The ionization cross sections are in good agreement with other calculations and the total cross section is in good agreement with experimental measurements for rare gas atoms and H2. We also discuss the extension of our methods to include the non-spherical nature of the electron-molecule interaction.
Experimental measurements of the total scattering cross section of Positronium (Ps) from various atomic and molecular targets are very similar to electron scattering cross sections above the Ps ionization threshold. This phenomenon has been explained theoretically using the impulse approximation. Below the ionization threshold the impulse approximation breaks down, and pseudopotential calculations have given good results for rare gas atoms. We apply the impulse approximation and the pseudopotential method to elastic scattering of Ps by H2 by assuming that H2 is spherically symmetric. We have supplemented the elastic cross sections by calculation of the Ps ionization cross section using a binary encounter approach. The ionization cross sections are in good agreement with other calculations and the total cross section is in good agreement with experimental measurements for rare gas atoms and H2. We also discuss the extension of our methods to include the non-spherical nature of the electron-molecule interaction.