A detailed study has been made of electron impact induced fluorescence from Ar clusters. Use of suitable filters in the vacuum ultraviolet spectral region together with time-resolved, techniques has enabled the dimer emission from the clusters to be investigated in detail. Excitation function measurements have revealed a number of processes leading to exciton production. Two-center collisions within the cluster appear to be significant. A close parallel to what is observed with solid Ar targets is noted. (C) 1997 American Institute of Physics. [S0021-9606(97)02241-1].