ELECTRON IMPACT SPECTROSCOPY

Author Institution: Jet Propulsion LaboratoryAtomic and molecular species can be readily excited by electron impact into all degrees of freedom (electronic, vibrational, rotational excitations, elastic and superelastic scattering, ionization, dissociation, and electron capture). The study of these excitation processes, the determination of the energy levels of the target molecule, the measurement of the cross sections associated with these processes, and the variation of the cross sections with electron impact energy and scattering angle are the subjects of electron impact spectroscopy. The similarities and differences between optical and electron impact spectroscopy and the question of selection rules for electron impact excitations will be discussed. As an example, the spectra of $O_{2}$ will be presented to demonstrate the methods and capabilities of electron impact spectroscopy