An electron spin resonance study of dimeric, trimeric, and tetrameric paramagnetic silver atom clusters

The low temperature γ-irradiation of frozen benzene solutions containing AgClO 4 leads directly to the formation of the paramagnetic species Ag 2 + , no Ag 0 centre being detected. When benzene or toluene solutions containing AgBF 4 were similarly treated and the matrix carefully annealed, well-resolved E.S.R. spectra attributed to paramagnetic clusters containing three and four equivalent silver atoms were detected. The lack of resolved anisotropy in the spectrum of the trimer and tetramer are thought to argue in favour of a triangular and tetrahedral geometry respectively rather than linear chains.