| Sumario: | In this paper we report ionization cross sections of positive Li +, Na+, K+, Rb+, neutral He, Ne, Ar, Kr, Xe, and negative F-, Cl-, Br-, I - ions by impact of protons with energies ranging from 25 to 1000 keV. Cross sections of singly charged ions are relevant to the calculation of electron yields in collisions with insulator surfaces. Calculations were performed within the continuum distorted wave-eikonal initial state method using an angular expansion in spherical harmonics and a numerical evaluation of the radial functions corresponding to both the initial (bound) and the final (continuum) states. The first Born approximation was used on an equal footing. We find that this first-order theory holds for proton energies larger than 300 keV. For comparison, we also calculate the shellwise local plasma approximation. Our results show that it gives a good account of the cross sections for neutral targets. © 2008 The American Physical Society.
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