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Coevaporation of C60 and an alkali metal in a gas aggregation cell yields a distribution of clusters with composition (C60)nMx with 0≤x<150, n=1,2,3, and M=Li, Na, and K. For singly ionized clusters the mass peaks are strong for odd values of x but only after reaching the composition C60M7+. It is suggested that the onset of even–odd alternation marks the end of electron transfer between metal and C60 and the beginning of metal–metal bonding.

Clusters of group IV B elements have been produced and observed in a mass spectrometer. Irregularities in the ion intensities identify clusters with particularly high or low stability. For example, Si+x,Ge+x, and Sn+x show an enhanced stability for x=6, 10. However, Sn+14 is unstable, whereas Ge+14 is particularly stable.

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Geometric shell structure in the mass spectra of sodium clusters was found to disappear as the clusters were heated. The exact temperature at which the shells disappeared was dependent on the size of the clusters. These observations are interpreted as evidence for a size-dependent melting. Clusters containing 1000 atoms appear to melt at 288 K, clusters containing 10 000 atoms at 303 K. Both values lie well below the bulk melting temperature of 371 K.