We report the 790 nm photofragmentation of mass-selected I-2(-). Ar-n clusters, n=1 to 27. We determine the I-+I caging efficiency as a function of the number of solvent Ar atoms and compare these results with I-2(-) in CO2 clusters. Caging is much less effective with Ar. In addition to "normal" caged photoproducts (I-2(-). Ar-m, where m5 mu s, This unusual photofragment exists either as a trapped excited electronic state or as a solvent-separated pair at an internuclear separation of similar to 5.5 Angstrom. The photofragmentation data also exhibit the existence of two distinct isomeric forms of the precursor I-2(-). Ar-n, for n less than or equal to 14. These forms are evaporatively distinct in that one isomer displays highly nonstatistical fragmentation, probably arising from a cluster in which the I-2(-) resides on the surface, rather than in the interior. The photofragmentation distribution of the other form exhibits statistical behavior, consistent with the evaporation of an I-2(-) solvated inside the cluster.