We report the results of the analysis of the temperature broadening of the momentum distribution of delocalized positronium (Ps) in magnesium fluoride in terms of the optical deformation-potential scattering model (long-wavelength optical phonons). The Ps optical deformation-potential coupling constant Do in MgF2 has been determined to be (1.8±0.3)×109 eVcm. We also show that the Ps momentum distribution is sensitive to second-order phase transitions in those crystals where optical deformation-potential scattering is allowed in one and forbidden in another crystalline phase.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2005|