Electron-impact excitation of electronic states in argon at incident energies between 16 and 100 eV

Abstract

Normalized, absolute differential cross sections have been measured for electron-impact excitation of 23 individual or composite electronic states of argon lying within 14.30 eV of the ground state. Incident electron energies are 16, 20, 30, 50, and 100 eV, and the range of scattering angles 5\ifmmode^\circ\else\textdegree\fi{}-138\ifmmode^\circ\else\textdegree\fi{}. The absolute differential cross sections are extrapolated to 0\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} and integrated to yield integral and inelastic-scattering momentum-transfer cross sections for the excitation processes. Errors in the differential cross section are grouped into the classes $A(26%)$, $B(31%)$, and $C(45%)$, with slightly larger errors given to the integrated quantities owing to extrapolation uncertainties. Comparisons of the present data are made with previous measurements where available, and with results of several distorted-wave and Born calculations. Differential magnetic sublevel cross sections for the $^{3}P_{1}$ and $^{1}P_{1}$ levels are also obtained at 50-eV incident energy and 5\ifmmode^\circ\else\textdegree\fi{} scattering angle using previously measured $\ensuremath{\lambda}$ parameters.