Differential Spin Exchange and the Elastic Scattering of Low-Energy Electrons by Potassium

Results are reported on the elastic scattering of low-energy electrons by potassium. The atomic-beam crossed-beam recoil technique is used, with velocity selection and spin selection and analysis of the atom beam. The results include total, differential, and differential spin-exchange cross sections, in the energy range 0.5-1.2 eV. Comparison is made with close coupling, as well as with adiabatic-type calculations. Additional total cross-section measurements up to 9 eV are also presented. These are significantly smaller and lack the pronounced structure of the early results of Brode.