The Ionization by Electrons of the Excited 2s and 2p States of Atomic Hydrogen

Abstract

The cross sections for ionization by electrons of H2s and H2p have been evaluated in the energy range 5-100eV. First order perturbation theory is employed, the ejected electron being described by a Coulomb wave function, and the bombarding electron by plane waves both before and after collision. The H2s cross sections are larger than the H2p values, but both are much greater than the cross section for ionization of the ground state H1s. The classical cross section formula agrees roughly with the H2p (m= ±1) results, but is considerably smaller than the H2p (m=0) and H2s cross sections.