Point defect energy

A useful way to approach these individual point defect energies is to define the energy per mole or cohesive energy of perfect material with respect to separated free atoms, Cmoi-We can then arbitrarily divide this between the atoms of type A and B so that ... 

In terms of the point defect energies so defined, our stoichiometry-conserving defects have formation energies given by ... 

Formula for the chemical potentials have been derived in terms of the formation energy of the four point defects. In the process the conceptual basis for calculating point defect energies in ordered alloys and the dependence of point defect concentrations on them has been clarified. The statistical physics of point defects in ordered alloys has been well described before [13], but the present work represents a generalisation in the sense that it is not dependent on any particular model, such as the Bragg-Williams approach with nearest neighbour bond energies. It is hoped that the results will be of use to theoreticians as well as... 

Mackrodt W. C. and Stewart R. F. (1979). Defect properties of ionic solids, II Point defect energies based on modified electron gas potentials. J. Phys., 12C 431 49. 

The concepts required for a quantitative treatment of the reactivity of solids were now clear, except for one important issue. According to the foregoing, point defect energies should be on the same order as lattice energies. Since the distribution of point defects in the crystal conforms to Boltzmann statistics, one was able to estimate their concentrations. It was found that the calculated defect concentrations were orders of magnitude too small and therefore could not explain the experimentally observed effects which depended on defect concentrations (e.g., conductivity, excess volume, optical absorption). Jost [W. Jost (1933)] provided the correct solution to this problem. Analogous to the fact that NaCl can be dissolved in H20... 

Little is known about estimating the point defect energy of covalent crystals or molecular crystals. In the zeroth approximation one can proceed, as for ionic crystals, via the lattice energy Uj which can be estimated from the enthalpy of sublimation and the zero point energy. 

The point defect energy of metals consists essentially of two terms 1. the change in the... 

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