Transport positron-atom elastic scattering cross sections have been computed for kinetic energies in the range 500-4000 eV. The phase shifts have been calculated by numerically solving the Dirac equation for a central electrostatic up to a large radius in which the atomic potentials are negligible. The atomic potential was that of Hartree-Fock for the atomic numbers smaller than or equal to 18 and that of Dirac-Hartree-Fock-Slater for the atomic numbers greater than 18. An analytical expression depending on three parameters, obtained by fitting the numerical results, is proposed for the energetic range examined to calculate transport cross sections for positron-atom elastic scattering in the atomic number range 1-92. The accuracy of the given expression for energies lower than 500 eV and greater than 4000 eV has been discussed by comparison with other tabulations.
Analytical transport cross section of medium energy positrons elastically scattered by complex atoms (Z=1-92)
Dapor, Maurizio
1995-01-01
Abstract
Transport positron-atom elastic scattering cross sections have been computed for kinetic energies in the range 500-4000 eV. The phase shifts have been calculated by numerically solving the Dirac equation for a central electrostatic up to a large radius in which the atomic potentials are negligible. The atomic potential was that of Hartree-Fock for the atomic numbers smaller than or equal to 18 and that of Dirac-Hartree-Fock-Slater for the atomic numbers greater than 18. An analytical expression depending on three parameters, obtained by fitting the numerical results, is proposed for the energetic range examined to calculate transport cross sections for positron-atom elastic scattering in the atomic number range 1-92. The accuracy of the given expression for energies lower than 500 eV and greater than 4000 eV has been discussed by comparison with other tabulations.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
