Computation of the energetics of surface vacancy and interstitial generation in silver halide

摘要: We have considered alternative mechanisms through which flat, stepped, or kinked surfaces of silver halide may participate in the generation interstitial vacancy ions. In energetically favored mechanism, surface sites ionize to generate an adsorbed ion and a vacancy. The former has smaller energy requirement for exchange into bulk than latter, as deduced from our calculations. Positive kink require smallest overall this step compared flat {100} stepped {105} surfaces. nature space-charge layer involving negative charge subsurface ions agrees well with accepted experimental picture. Computed energies these processes are presented along preliminary estimate entropy formation point defects AgBr surface. A calibration procedure NaCl is made by comparison calculated enthalpy values vacancies shows excellent agreement.