The high-n Rydberg time-of-flight (HRTOF) technique has been used to obtain translational energy distributions of hydrogen atoms deriving from weakly-bound (HI)(2) clusters photoexcited at 266 nm. A number of distinct features were observed and were used to establish much of the photophysics and photochemistry. Though the geometric structure of (HI)(2) has not been determined experimentally, equilibrium geometries have been estimated by using several semiempirical theoretical methods, all of which predict an approximately 90 degrees L-shaped structure with one hydrogen localized between the two iodine atoms (the interior hydrogen) and the other pointing outward (the exterior hydrogen). Zero-point amplitudes are expected to be large. The photolytic removal of the exterior hydrogen yields I-HI and I*-HI radical-molecule clusters whose properties can be described, at least qualitatively, by using the formalism put forth by Hutson and co-workers, who carried out detailed calculations for the analogous Cl + HCl system. Photodissociation of the HI moiety whose hydrogen is interior can also yield radical-molecule clusters, as well as initiate intracluster reactive and/or inelastic scattering processes.