Recent Appearance Potential Measurements Using an Electrostatic Electron Selector

Abstract

The general principles of measuring appearance potentials by the electron bombardment method are reviewed. Recent improvements in the design of an electrostatic electron selector so as to improve the electron bombardment technique are described. The new instrument provides an electron beam with an energy spread of less than 50 mv. By means of it, measurements have been made on the vibrational levels N₂⁺ and H₂⁺.