Improved algorithm for calculating transport cross sections of electrons with energies from 50 eV to 30 keV

We report an analytical expression for transport cross sections (TCSs) calculated from the Dirac-Hartree-Fock potential for 92 elements (H to U) and electron energies between 50 eV and 30 keV. This expression is the product of an approximate TCS formula and a correction function. Parameters in the correction function were obtained from separate fits for each element to computed TCSs for energies between 50 and 300 eV and between 300 eV and 30 keV. Over the entire energy range, the mean deviation between TCSs from the expression and the calculated TCSs for any element was typically between 0.01% and 0.5%, and the maximum deviation was between 0.1% and 3%; both deviations generally increased with atomic number. The TCS expression will facilitate evaluation of parameters needed for quantitative Auger-electron spectroscopy and x-ray photoelectron spectroscopy that have been derived from the solution of the kinetic Boltzmann equation within the transport approximation.