Neutral and positively charged clusters produced by 4 keV ${\mathrm{Ar}}^{+}$ ion bombardment of a liquid gallium-indium eutectic alloy have been studied by time-of-flight mass spectrometry coupled with single photon postionization of the neutrals. The abundance distributions for clusters with equal nuclearity are statistical. They confirm a strong indium surface segregation. An increasing gallium content, and, therefore, larger depth of origin, was found for increasing cluster size.

• Received 14 April 1994

DOI:https://doi.org/10.1103/PhysRevLett.73.1719