Formation of neutral In(m)C(n) clusters under C60 ion bombardment of indium

The formation of neutral gas phase indium carbide clusters under C60(+) ion bombardment of solid indium was investigated using laser based postionization prior to mass spectrometric detection. Two different postionization methods were used and shown to provide saturated photoionization efficiency, thereby delivering nearly the same information about the composition of the sputtered material. The resulting size distributions of neutral In(m)C(n) clusters are compared with those of the corresponding cationic secondary cluster ions and discussed in terms of calculated cluster properties. Investigating the dependence on C60(+) ion fluence, we demonstrate that clusters containing only one carbon atom are formed in single impact events, whereas the formation of more carbon-rich clusters results from carbon accumulation at the bombarded surface.