K-Shell Ionization of Beryllium by Proton and Heavy Ions

Abstract

Experimental cross sections are presented for the ionization of K-shells of beryllium in collision with heavy ions and proton; C ⁺ , N ⁺ , O ⁺ , Ne ⁺ and Ar ⁺ for bombarding energy ranging from 0.3 to 30 keV per amu, while that for protons is 10 to 200 keV per amu. Proton data show good agreement with the prediction for Coulomb excitation of K-shell electrons. The date for heavy ions are several orders of magnitude larger than that for proton. These results are understood in terms of pseudomolecule formation and crossings of molecular orbitals during the collisions. Heavy ion cross sections show the trend to converge to the theoretical Coulomb excitation cross sections in high energies above about 10 keV per amu.