A Detailed Theoretical Mechanism for Photographic Sensitization of the AgBr(111) Surface

Abstract

Recent experimental characterization of the reconstructed AgBr(111) surface (a half-layer covering of Ag ions segregated into rows 7.07 Å apart) has been used to construct a theoretical model (within the framework of an approximate molecular orbital method) of that surface. Our calculations indicate that these surface Ag rows give rise to states at the bottom of the conduction band, which could serve as shallow trapping sites for photoelectrons. The theoretical model provides a mechanism for the formation of a latent image cluster through trapping of photoelectrons in the low lying state and subsequent pairwise distortion of the surface Ag within the rows to form Ag–Ag bonds. The calculations also indicate that substantial electron transfer from the ionic extreme occurs in both the bulk and surface models.