Nonpolar optical scattering of positronium in magnesium fluoride

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-...

Band structure and optical properties of magnesium fluoride

2014 The electronic band structure of magnesium fluoride is calculated by a combined tight binding and pseudopotential method in order to interpret the numerous experimental data. The gap anisotropy is clearly shown and the values of parallel and perpendicular gaps are in good agreement with the measured ones. A tentative interpretation of some other experimental transitions is given. LE JOURNA...

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...

Optical spectroscopy of molecular positronium.

We report optical spectroscopic measurements of molecular positronium (Ps(2)), performed via a previously unobserved L=1 excited state. Ps(2) molecules created in a porous silica film, and also in vacuum from an Al(111) crystal, were resonantly excited and then photoionized by pulsed lasers, providing conclusive evidence for the production of this molecular matter-antimatter system and its exci...

Near-threshold behavior of positronium-antiproton scattering