Exchange and correlation in positronium-molecule scattering

Electron exchange model potential: Application to positronium-helium scattering

The neutral Ps beam provides a great deal of advantage over charged projectiles as a probe to study the structure of atoms, molecules and surface. Recently, there have been a great deal of interest in positronium(Ps-) atom scattering due to the improvement of Ps sources and Ps beams. Total scattering cross section of ortho Ps, which has a larger lifetime than para Ps, have been measured for var...

Resonances in positronium-rubidium and positronium-cesium scattering

Scattering of ortho positronium (Ps) by cesium and rubidium atoms has been investigated employing a three-Ps-state coupled-channel model with Ps(1s,2s,2p) states using a time-reversal-symmetric regularized electronexchange model potential. We find a narrow S-wave singlet resonance at 5.057 eV of width 0.003 eV in the Ps-Rb system and at 5.067 eV of width 0.003 eV in the Ps-Cs system. Singlet P-...

Positronium-positronium interaction: Resonance, scattering length, and Bose-Einstein condensation

The low-energy scattering of ortho positronium (Ps) by ortho Ps has been studied in a full quantum mechanical coupled-channel approach. In the singlet channel (total spin sT = 0) we find Sand P-wave resonances at 3.35 eV (width 0.02 eV) and 5.05 eV (width 0.04 eV), respectively and a binding of 0.43 eV of Ps2. The scattering length for sT = 0 is 3.95 Å and for sT = 2 is 0.83 Å. The small sT = 2...

Near-threshold behavior of positronium-antiproton scattering

Unusual nature of positronium-proton elastic scattering.

The Lippmann-Schwinger equation for positronium-proton elastic scattering lacks a first-order term because the center of mass and center of charge are coincident. A consequence of this is that the high-energy behavior of the phase shift is governed by the second-Born approximation. Asymptotic analysis indicates that the high-energy form of the phase shift is dL;O(1/k ), where k is the incident ...