Electron impact excitation of the argon3p54s configuration: differential cross-sections and cross-section ratios

Abstract

New electron-impact differential cross-section (DCS) and DCS ratiomeasurements for the excitation of the four levels making up the3p54s configuration of argon are reported at incident electron energies of 14, 15, 17.5, 20,30, 50 and 100 eV. These cross-sections were obtained using a conventional highresolution electron spectrometer. Elastic electron scattering from argon was usedas a calibration standard. Electron–helium DCSs were used to determine theinstrumental transmission of the spectrometer. Further checks of the relative shape ofthese DCS measurements were made using the method of gas mixtures (Ne mixedwith Ar). We also present results from new calculations of these DCSs using theR-matrix method, the unitarized first-order many-body theory, the semi-relativisticdistorted-wave Born approximation, and the relativistic distorted-wave method.Comparison with available experimental DCSs and DCS ratios is also presented.