Absolute Measurements of Total Cross Sections for Electron Scattering by Sodium Atoms (0.5-50 eV)

Absolute measurements have been made of total cross sections for the scattering of electrons by sodium over the electron energy range 0.5-50 eV; some new data for potassium at 10, 20, and 50 eV are also presented. The measured cross sections for sodium range from 352 ${\mathrm{\AA }}^2$ at 0.5 eV, to 57 ${\mathrm{\AA }}^2$ at 50 eV, with over-all uncertainty of 13%. At very low energies, the 250-meV energy spread in our experiment introduces additional uncertainty. As with earlier measurements from this laboratory using potassium, we find excellent agreement with close-coupling calculations.