Extended Polarization Potential: Applications to Atomic Scattering

Abstract

In the calculation of the scattering of low-energy charged particles by atoms, corrections must be made to the usual polarization potential. The most important of these is a distortion potential, arising from the action of the kinetic-energy operator for the scattered particle on the perturbed wave function for the atom. A formal expression for this potential is obtained for any atom. It is evaluated approximately for hydrogen and helium. The combination of the distortion potential and the ordinary polarization potential is called the extended polarization potential; it is much weaker than either separately. Calculations of the scattering of low-energy positrons and electrons by hydrogen and helium atoms are performed in which the extended polarization potential is employed. Computed phase shifts and cross sections are compared with experiment and with other theoretical calculations.