Positron-sodium and positron-lithium scattering using CCA

The eigenstate expansion method has been employed to study elastic and excitation processes for e + -Na and e + -Li scattering. Various target bases are used in the coupling scheme to find the effect of higher excited states on the elastic and inelastic scattering parameters. In both systems, the effect of added eigenstates in the expansion of the total wavefunction is significant at low and intermediate energies. The calculation of e + -Li scattering is an extension of the investigations of Khan et al. The elastic and excitation cross sections are predicted for e + -Na and e + -Li in the energy ranges 4-100 and 15-100 eV respectively. The convergence of the elastic and excitation cross sections is discussed. Total cross sections for e + -Li and e + -Na scattering have been compared with the corresponding measured values of e-Li and e-Na scattering. The inelastic collisions dominate the scattering.