Secondary ion emission: Pt. 2

Using experimental values of the relative yields of positive and negative secondary ions for 31 pure elements and 9 compounds bombarded with 13.5 keV Cs+ ions the temperatures of the sputtering centers, Tsc, have been determined. Similarly, the degrees of ionization of sputtered atoms, α+ and α-, have been determined from M+ and M- yields and an assumed secondary ion transmission efficiency of 1%. Two non-equilibrium equations of surface ionization (NESI) were used to determine Tsc. The calculated temperatures, as well as the degrees of ionization, have periodic dependence on the atomic number of the target, Z2. Most of the calculated temperatures are lower than the boiling temperatures, Tb, of bombarded targets and for refractory elements Tsc values are even lower than the melting temperatures, Tm. However, Tsc for most of the amphoteric and non-metallic elements are higher than Tb but lower than their critical temperatures, Tc. (author)