INTERMEDIATE ENERGY ELECTRON-SCATTERING FROM POTASSIUM

Differential cross sections for elastic and inelastic electron scattering from potassium are presented in the energy range 54.4 to 217.7 eV and over the angular range from 2 degrees to 145 degrees . The experimental cross sections for elastic scattering are compared with our optical-model calculation which is in excellent agreement with the experiments at 200 eV. At lower energies the agreement becomes progressively worse. Comparison is also made with other intermediate energy theories. The inelastic differential cross sections are compared with previous theoretical calculations where it is found that the theories are inadequate in their description of the differential cross section over the entire angular range. Total cross sections for the resonance transition have been deduced by integrating the differential cross sections. These cross sections are in good agreement with previous measurements.