Low energy elastic scattering of electrons by Li and Na

Resonance structure previously obtained in low energy phase shifts for elastic scattering of electrons by Li and Na for total L=0 is shown to be the consequence of a lack of uniqueness in the asymptotic solutions of the coupled equations. An algorithm is developed for obtaining unique asymptotic solutions, and new low energy phase shifts computed. A modified form of the scaled Thomas-Fermi statistical model potential including core polarization is used for the target in the coupled equations formulation of the scattering problem. The results conform to the well known modified effective range formula, and exhibit no resonance structure whatsoever.