Sulfide centers on (111) AgBr surfaces: Characterization

Sensitometric and spectroscopic techniques are used to characterize sensiti zer centers produced by sulfur sensitization of AgBr octahedra. Sulfur sens itization primarily affects the long wavelength sensitivity in two spectral regions--around 550 nm and around 650-700 nm. The concentration dependence of the long wavelength sensitivity in these two regions shows the former t o be associated with single-sulfide centers and the latter to be associated with double-sulfide centers. The achievement of maximum photographic speed is associated with the production of the double-sulfide centers. A promine nt 495 nm peak is observed in diffuse reflectance spectroscopy of these emu lsions that is not observed in the long wavelength sensitivity measurements . This peak is assigned to a product of the sulfur sensitization that is no t photographically active.