Angular correlations in the electron-impact excitation of sodium.

Abstract

An electron-photon coincidence technique has been used to measure an angular-correlation function for the excitation of the 3 $^{2}P$ state in sodium at an incident electron energy of 54.4 eV; the scattered electrons are detected at 5\ifmmode^\circ\else\textdegree\fi{}. It is shown that the depolarizing influence of the hyperfine structure in the excited state is such that the angular correlation is essentially isotropic. Thus severe limitations are imposed on the use of this technique for the study of scattering amplitudes in the electron-impact excitation of sodium atoms.