Scaling of cross sections forK-electron capture by high-energy protons and alpha-particles from the multielectron atoms

Abstract

Electron capture by protons from H, He, and the $K$ shell of Ar, and electron capture by alpha particles from He are considered. Using the experimental data, a function of the capture cross section is formed. It is shown that when this function is plotted versus the inverse of the collision energies, at high energies a straight line is obtained. At lower energies the line is concave up or down, depending on the charge of the projectile and/or the effective charge and the ionization potential of the electron that is being captured. The plot can be used to predict cross sections where experimental data are not available, and as a guide in future experiments. High-energy scaling formulas for $K$-electron capture by low-charge projectiles are given.