Electron–ion coincidence measurements: The neutral dissociation plus excitation cross section for N2

Abstract

Pulsed electron beam time-of-flight measurements of the electron energy loss spectrum of molecular nitrogen at scattering angles of 28°, 45°, 71°, 112°, and 135° were made at impact energies of 24.5, 33.1, and 33.6 eV in coincidence with positive ions. The angular-dependent elastic, total inelastic, ionization, and neutral dissociation plus excitation cross sections were measured. The data were integrated over electron energy loss for each scattering angle. These angular-dependent data were then fitted with smooth analytic functions and integrated over angle to obtain individual total cross sections. All cross-section data were placed on an absolute scale by matching to total cross-section measurements reported in the literature. The angular-dependent elastic cross section and the integrated cross sections for elastic and total inelastic scattering were found to be in good agreement with literature values. Values obtained for the neutral dissociation plus excitation cross section agree with the sum of previous separate measurements of neutral dissociation and excitation. The total ionization cross sections are in fair agreement with accurate values reported in the literature.