The dissociative photodetachment dynamics of (SO2)(3)(-) were studied by photoelectron-photofragment coincidence spectroscopy at 258 nm. Correlation between the photoelectron and photofragment translational energies was observed as previously seen in the dimer system, implying the presence of a dimer core. The three-body dissociation dynamics of (SO2)(3) after photodetachment are consistent with a dimer core solvated by a spectator SO2 molecule with a broad distribution in initial geometry. (C) 2002 Elsevier Science B.V. All rights reserved.