ELECTRON-ION COINCIDENCE MEASUREMENTS - THE NEUTRAL DISSOCIATION PLUSEXCITATION CROSSSECTION FOR N-2

Pulsed electron beam time-of-flight measurements of the electron energ y loss spectrum of molecular nitrogen at scattering angles of 28 degre es, 45 degrees, 71 degrees, 112 degrees, and 135 degrees were made at impact energies of 24.5, 33.1, and 33.6 eV in coincidence with positiv e ions. The angular-dependent elastic, total inelastic, ionization, an d neutral dissociation plus excitation cross sections were measured. T he data were integrated over electron energy loss for each scattering angle. These angular-dependent data were then fitted with smooth analy tic functions and integrated over angle to obtain individual total cro ss sections. All cross-section data were placed on an absolute scale b y matching to total cross-section measurements reported in the literat ure. The angular-dependent elastic cross section and the integrated cr oss sections for elastic and total inelastic scattering were found to be in good agreement with literature values. Values obtained for the n eutral dissociation plus excitation cross section agree with the sum o f previous separate measurements of neutral dissociation and excitatio n. The total ionization cross sections are in fair agreement with accu rate values reported in the literature. (C) 1998 American Institute of Physics.