Energy Distribution of Secondary Ions Emitted from Silicate Minerals

One of the approaches to clarify the emission mechanism of secondary ions is to study the kinetic energy distribution (ED). THOMPSON [1] proposed that the most probable energy E_m is near E_b/2, where E_b is the binding energy for metal targets. SIGMUND [2] discussed the nature of the binding energy and proposed to take sublimation energy as E_b for metals and cohesive energy per atom for covalent crystals. SCHROEER [3] deduced a formula for the ionization efficiency of sputtered atoms from metals based on a quantum mechanical model. Using the Schroeer result, GRIES and RUEDENAUER [4] obtained an expression for the ED of secondary ions which leads to E_m=0.768E_b for metals.