Elastic stopping of fast heavy ions by electrons in solids

Abstract Stopping of fast heavy ions by electrons in solids is studied. The contribution of elastic (with respect to the bombarding ion) scattering is shown to dominate in the velocity interval Z 1 1/3 vo< v < Z 1 2/3 vo (vo is the Bohr velocity, v and Z 1 are the velocity and atomic number of the projectile). Known experiments show a more rapid increase of stopping cross-section with v for velocities of the order of Z 1 1/3 vo than the existing theories predicted. We explain such increase as due to elastic scattering, and analyse the velocity dependence of stopping cross-section for higher velocity values.