Extension of the single-channel MCHF method to include multichannels

The multiconfiguration Hartree-Fock (MCHF) method for single open channel has been extended to include multi-open channels. The coupled integro-differential equations satisfied by the radial wavefunctions of the multi-open channels associated with the scattering of electrons by atoms and ions at low energies are solved completely numerically self-consistently in the MCHF approximation to obtain the required linearly independent solutions. The asymptotic scattering parameters obtained from these solutions are used to calculate cross sections. The electron correlation and polarization effects which are very important for scattering of electrons at low energies can be obtained completely ab initio through the configuration interaction procedure. The extended method is now capable of performing calculations for both elastic and inelastic scattering processes. As a test case, we have calculated contributions to both elastic and inelastic cross sections for scattering of electrons from hydrogen and helium atoms as well as ionized helium at a few low energies for few partial waves including a few open channels. Our results are compared with similar data obtained by other existing approximate methods and are found to be in excellent agreement confirming a successful extension