Resonance scattering of low-energy electrons from potassium atoms

The elastic and inelastic differential cross sections for electron-potassium scattering have been measured in a crossed-beam experiment in the energy range 2 to 3.2 eV and for scattering angles from 20 degrees to 140 degrees . In the elastic channel three resonances have been observed at 2.4 eV, 2.6 eV and 2.68 eV and were found to be S, D and P (or F) states respectively. The lifetime of the D resonance was estimated to be 1.0*10 -14 s+or-20%. In the excitation function of the 4 2 P channel at least one resonance has been observed, the shape of which appears to be overlapped by threshold effects at 2.6 eV.