Scattering of electrons by Cs atoms at low energies

Abstract

Electrons are scattered elastically by caesium atoms in a crossed-beam experiment. The dependence of the cross section on collision energy and scattering angle has been measured; the collision energies studied are in the range from 0.8 to 20 eV. Resonant structures are observed in the elastic cross section at an energy of 1.49 eV and around the 62P1/2 threshold at 1.39 eV. It is believed that the 1.49 eV resonance is due to an autoionising F state of Cs- which is consistent with theoretical predictions. The angular distributions of the elastic cross section agree satisfactorily with theory for collision energies below 2 eV. At higher energies larger deviations from theory are observed.