Numerical calculations of elastic scattering amplitudes for high-energy electron scattering by ionized atoms

The elastic electron scattering factors and phases for eleven alkali and halide ionized atoms, Li⁺, Li²⁺, Li³⁺, Na⁺, K⁺, Rb⁺, Cs⁺, F^-, CI^-, Br^- and I^-, have been calculated by the partial wave method for impact energies of 10, 40, 70 and 100 keV. Clementi analytic Hartree-Fock wavefunctions were used except for Li²⁺ whose wavefunction was hydrogen-like, Li³⁺ whose potential was purely Coulombic, and Rb⁺, Cs⁺, Br^- and I^- for which potential functions estimated from the X-ray scattering factors were used. The calculated scattering factors and phases for the ionized atoms have been compared with those for neutral atoms in International Tables for X-ray Crystallography [(1974). Vol. IV, pp. 176-269. Birmingham: Kynoch Press]. It has been found that the difference in the scattering phase between the neutral and ionized atom is almost constant except for small s and that the magnitude of the difference for a given valence of the ionized atom and a particular impact energy is nearly independent of the atomic number.