Using a recently developed multicoincidence technique, fragmentation resulting from collisions between high energy $(60\mathrm{}\hspace{0.5em}\mathrm{k}\mathrm{e}\mathrm{V}/\mathrm{u})$ ${\mathrm{H}}_{27}^{+}$ ions with an He target are investigated on an event by event basis. The data obtained are analyzed in terms of fluctuations in the fragment size distribution. A comparison with results from two different three-dimensional (3D) lattice bond percolation models of the same size (27 constituents) indicates the presence of a critical behavior in the decaying finite system and the importance of accounting in the percolation model for the specific binding situation in the hydrogen cluster ion.

• Received 25 September 2000

DOI:https://doi.org/10.1103/PhysRevA.63.033202