Ag cluster formation on AgBr is probed in three ways. First, qualitative orbital arguments, largely based on symmetry considerations, are introduced to determine which AgBr surfaces are more likely to lead to silver cluster formation induced by photoelectrons. The analysis indicates that silver atoms on the (111) surface and the troughs and wedges of a twin plane are likely to form clusters. Silver atoms on (100) and (110) surfaces do not appear to possess the electronic features favoring cluster formation. Second, DFT electronic structure calculations performed on cluster models produced trends similar to those emerging from the group theoretical analysis. Third, we looked at electron density shifts in models specifically constructed to create contrasting bonding environments on AgBr surfaces. An increase in electron density on the essential silver atoms is observed in a triplet state model for photoinduced cluster formation.