Negative Secondary Ion Mass Spectrometry of Gold Surfaces

Abstract

Gold surfaces have often been used as supports or backings for thin layers of solid samples to be studied by secondary ion mass spectrometry (SIMS). We have observed that a sublimed gold surface yields a multitude of oligomeric gold-oxygen-hydrogen anions on bombardment by Cs⁺ ions. Despite the wide use of gold substrates for SIMS we could not find a precedent for this observation and we present an outline of our findings here. The results are of interest both from practical and theoretical viewpoints. In practice, one should be aware of possible background ions that can arise when gold surfaces are used as the sample supports. The theoretical interest lies in relating the composition of the gold-containing anions to the known structural chemistry of gold. The main experimental findings are summarized here.