THEORY OF AUGER EJECTION OF ELECTRONS FROM METALS BY IONS,

A theory of the ejection of electrons from atomically clean metals by slow ions of the noble gases arising from Auger transitions is presented. Scattering matrix elements are evaluated from first principles and the secondary ejected electron energy distribution and total yield are found. The approach used in the solution of this problem is that of the quantum theory of scattering. This approach eliminates determining transition matrix elements per unit time as a function of the distance of the ion from the metal surface, and will allow the direct calculation of the secondary electron energy distribution, total yield, spatial distribution, position of most probable neutralization, and depth of origination of Auger electrons. The formal solution is applied to the situation of He ions of low energy incident on atomically clean tungsten. Normal incidence is treated although the theory is not restricted to this case. Typical theoretical curves are presented and compared with the experimental results of others. A discussion of such effects as energy broadening, effective ionization energy, uncertainty principle effects, inelastic electron scattering, and density of electron states in metals is included. Author