Electron scattering by atoms and ions using the Breit-Pauli Hamiltonian: an R-matrix approach

Abstract

The R-matrix method describing the scattering of low-energy electrons by complex atoms and ions is extended to include terms of the Breit-Pauli Hamiltonian. An application is made to the astrophysically important 1s22s2 1S0e-1s22s2p 3P1o transition in Fe XXIII, where in the most accurate calculations carried out all terms of the 1s22s2, 1s22s2p and 1s22p2 configurations are included in the expansion describing the collision. This gives up to 28 coupled channels for each total angular momentum and parity which are solved on a CRAY-1. The collision strengths are increased by more than a factor of two from their non-relativistic values at all energies considered.