Studies of anions from sputtering I: Survey of MFn-

Using AMS as high-sensitivity SIMS, the relative sputter yields of MFn- (n = 0–8) from Cs+ sputtered PbF2 matrices have been systematically assessed for most elements. M represents an element, which is either embedded into or already present at low levels in PbF2 matrices. The powdered crystal PbF2 is found to become electrically conducting in a Cs+ sputter source and, in this environment, an effective F and F− donor in near surface chemical reactions. This ensures that the surface reactions leading to the observed MFn- generally occur under the condition of abundant F/F− reactants, maximizing the intensities of the fluoride anions that in general have electron binding energies greater than that of Cl−. In the chemical literature, these anions are known as superhalogen anions [1].