Formation of Small Negative and Positive Cluster Ions of Gold, Silver, and Copper by Direct Laser Vaporization

摘要

Direct laser vaporization techniques have been employed to produce small cluster cations and anions of gold, silver and copper in an FTICR mass spectrometer using pure metal samples. In one configuration ions were produced by Neodymium:YAG laser irradiation directed co-linear with the magnetic field in the FTICR mass spectrometer while in the second laser light directed perpendicularly to the magnetic field was used. Relative kinetic energies of the aggregates, the relative intensities of positive vs. negative ions, and the nature of the neutrals in the plasma formed by direct laser vaporization are discussed. Keywords: Fourier transform ion cyclotron resonance mass spectrometry, Metal cluster ions, Direct laser vaporization, Noble metal clusters, Gold clusters, Silver clusters, Copper clusters, Semiconductor ions, Reprints. (AW)