Electron-impact excitation and ionization of atomic calcium at intermediate energies

Abstract

We present a comprehensive study of electron collisions with calcium atoms by using the con-vergent B-spline R-matrix method. Elastic, excitation, and ionization cross sections were obtained for all transitions between the lowest 39 physical states of calcium (except for 3p64s5g 3,1G) up to the 3p64s8s 1S state, for incident electron energies ranging from threshold to 100 eV. A multi-configuration Hartree-Fock method with nonorthogonal term-dependent orbitals was employed to generate accurate wave functions for the target states. Close-coupling expansions including the 39 physical states plus 444 pseudo-target states of calcium were used to check the sensitivity of the results to coupling to the target continuum. The cross-section dataset obtained from the large-scale calculations is expected to be sufficiently accurate and comprehensive for most current modeling applications involving neutral calcium.