The ionization potentials of clustered sodium atoms

Abstract Small clusters of sodium atoms have been produced by the isentropic flow of high pressure vapour through a small orifice. These clusters have been ionized by ultra-violet light and detected using a mass spectrometer. Clusters of up to eight sodium atoms have been observed and their ionization potentials have been measured. The ionization potentials of Na3 and Nas are 3.9 v and 4.0 v respectively, showing that even the smallest clusters tend to the value expected for a continuous drop of metal of the same size.