Many-body theory for positron interaction with atoms and atomic clusters

The Hartree-Fock equations are converted to a generalized eigenvalue problem using the B-spline basis with an exponential knot sequence. To achieve convergence, the self-consistency iterations of the occupied electron orbitals are performed initially for a reduced value of the electron Coulomb potential, followed by increasingit gradually to its final value.

Other techniques used to aid convergence are described.<br><br>For the Coulomb central potential, results are presented for electron orbital energies for a selection of atoms and negative ions, and are benchmarked against existing calculations. We also consider arbitrary well-behaved potentials usingthe harmonic potential as an example. We report a number of properties for the harmonically-confined electron gas, including the dipole polarizabilities in the HF and RPA approximations and compare with Thomas-Fermi model predictions both numerical and analytical.