Study of Cluster and Polyatomic Ion Formation by Mass Spectrometry

11 Study of Cluster and Polyatomic Ion Formation by Mass Spectrometry 

Investigations of cluster formation serve to explain the evaporation and atomization of sample material and ion formation processes. A further aim of cluster research is to find out under what conditions cluster or polyatomic ion formation can be influenced in order to avoid disturbing interferences and decrease the detection limits of elements. On the other hand, polyatomic ions have also been used as analyte ions for analysis, e.g. the application of MCs+ and MCs2+ dimeric and trimeric ions as analyte11 or of cluster primary ion beams (e.g., of bismuth and gold primary clusters)15 16 by the bombardment and sputtering of a solid surface in SIMS.17-21 Especially in SIMS, a multitude of cluster ions with high ion formation rates are observed.18 22 23 

Mass spectrometric studies of the formation of clusters and their ionization in plasmas have been of interest for more than four decades. Increasing research has been performed together with activities in cluster physics and chemistry because clusters may also be viewed as a link in the chain from atoms or molecules through small crystallites to a complete solid-state structure (important for materials research, nanotechnology or catalytic processes).24-26 Consequently, clusters can also be considered as a bridge between the disciplines of physics and chemistry.27 Therefore, the aim of 

Van der Waals clusters (N2) (C02) noble gas clusters Molecular clusters (L2)n clusters of organic molecules H-bonding clusters (H20)  

Pioneering work on the mass spectra of Na clusters by Knight et at.34 provided the first insight that clusters and nuclear physics have something in common. They observed that Na clusters consisting of 2, 8, 10 and 40 atoms were unusually stable and coincided with the magic number in nuclear physics where nuclei with the same numbers of protons and/or neutrons were known to be very stable.34 

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