Nearest-neighbor distances in microclusters

The average nearest-neighbor distances of model microclusters, which do not exhibit normal bulk-like packing of the atoms, have been calculated indirectly from the interference function, I(k), assuming that the packing of the microclusters is a normal lattice packing. Physically correct results obtained directly from the radial distribution function (RDF) differ from those calculated from I(k). The RDF nearest-neighbor distances generally exceed the bulk distances while those evaluated from I(k) are less than the bulk values. Recent experimental reports that the nearest-neighbor distances in microclusters, based on measurements of I(k), decrease with decreasing cluster size may thus be incorrect. The error arises from assuming the wrong packing in interpreting the interference function.