Cluster-ion formation in pulsed-laser-stimulated field desorption of condensed materials

In pulsed-laser-stimulated field desorption of condensed materials on an emitter surface, multi- atomic cluster ions can be formed. Some of these cluster ions may dissociate into smaller cluster ions and atomic ions, or atoms. This dissociation process can be studied in a time-of-flight mass and energy spectrometer. If the dissociation proceeds spontaneously at a constant rate, an exponentially decaying low-energy tail should appear in the ion energy distribution of the dissociation products. If the dissociation occurs within a finite spatial zone, then a secondary peak should appear in the ion energy distributions. We present here a study of pulsed-laser-stimulated field desorption of condensed He, Hg, NaI, and ${\mathrm{H}}_2$O on metal surfaces.