Large angle elastic scattering of electrons from Ar+

Abstract

Absolute angular differential cross sections have been experimentally determined for large angle scattering of a free electron by a positive ion for the first time. Data are presented for elastic scattering over the range 120\ifmmode^\circ\else\textdegree\fi{}--170\ifmmode^\circ\else\textdegree\fi{} from Ar ${}^{+}$ at 3.3 eV. Interference effects are observed due to the competing short-range and Coulomb interactions. The importance of interference and correlation effects is demonstrated, and the consequent sensitivity of such measurements as a test of theoretical approximations is discussed.