Elastic Differential Spin-Exchange Cross Sections for Scattering of Slow Electrons by Potassium

We have measured the differential spin-exchange cross section ${\sigma }_{\mathrm{ex}}\left(\theta \right)$ relative to the differential cross section $\sigma \left(\theta \right)$ for the scattering of 0.5-eV electrons by potassium, for angles between 10° and 180° in the electron polar scattering angle. The ratio $\frac{{\sigma }_{\mathrm{ex}}\left(\theta \right)}{\sigma \left(\theta \right)}$ increases monotonically from approximately 0 at 10° to 0.7 ± 0.1 at 180°.