Computer simulations were used to study twin planes in such halides. It was noted that the formation energies of Ag and halide twin planes were roughly equal in AgCl, but that the halide component was significantly smaller in AgBr. The Madelung potential was attenuated at twin planes; thus promoting electron trapping at Ag, and hole trapping at halide twin planes. The formation energies of components of the Frenkel defect were reduced at the twin plane, as compared to the perfect crystal.

R.C.Baetzold: Journal of the Physics and Chemistry of Solids, 1996, 57[5], 627-34