The interaction of atomic particles with solid surfaces at intermediate energies II. Scattering processes

Abstract

Measurements were made of the energy distributions of charged particles emitted from targets of platinum, nickel and molybdenum bombarded by atomic and molecular positive ions of hydrogen, deuterium , helium , carbon, nitrogen, oxygen, neon, argon and carbondioxide, with energy 2 to 40 keV. It is shown that the scattering of incident particles is predominantly elastic and approximately independent of the charge state of the incident particle. Hydrogen, deuterium, carbon and oxygen are scattered with both positive and negative charges, but CO2gives only negatively charged scattered particles. Scattering with positive charge increases over an energy range 2 to 15 keV per incident particle, while scattering with negative charge increases to a maximum at incident energies 3 to 7 keV per particle and then decreases up to the highest energies used, 40 keV. Scattering with positive and negative charges is of the same magnitude at the incident energy corresponding with the maximum for negative scattering of hydrogen ions. The energy distribution of negatively charged scattered ions is generally broader than that for positively charged scattered ions at the same incident energy, for the lighter ions. Scattering as neutral atoms is estimated roughly and is shown to increase rapidly as the bombarding energy is reduced below about 10 keV.