Ionization of Boron, Aluminum, Gallium and Indium by Electron Impact
Yong Sik Kim, Philip M. Stone
Measurements of electron impact of ionization of neutral Al, Ga, and In show large cross sections compared to other elements in the same rows of the periodic table. Semi-empirical and classical calculations of direct ionization cross sections are all substantially smaller. Calculations by McGuire for aluminum that include the indirect ionization processes of excitation to autoionizing 3s3p2 doublet levels are too high by a factor of about 2.5 at the peak. In this paper we report the direct ionization cross sections using the binary-encounter-Bethe model of Kim and Rudd, which is an ab initio theory. We add the autoionization contribution using scaled plane-wave Born cross sections as recently developed by Kim for excitations to the first set of autoionizing levels. Dirac-Fock atomic wave functions are used for the atomic structure. Our results are in excellent agreement with experimental values and support substantial contributions from excitation-autoionization to the total ionization cross sections for these elements. We also compare the total ionization cross section of boron to available theories, though no experimental data are available.
Physical Review A (Atomic, Molecular and Optical Physics)
and Stone, P.
Ionization of Boron, Aluminum, Gallium and Indium by Electron Impact, Physical Review A (Atomic, Molecular and Optical Physics), [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=840508
(Accessed June 10, 2023)