Point defect simulations by finite cluster method

We present here a systematic scheme of calculating the point defect parameters by studying finite clusters and obtain the thermodynamic limits to calculate defect properties. This is an attempt to minimize the approximations introduced by the present quasi-lattice Mott–Littleon technique. The scheme is computationally more demanding as far as the computational algorithm is concerned. The usefulness of the scheme is demonstrated by estimating Schottky energy in the well studied NaCl crystal. The estimated energy compares fairly well with the existing experimental and theoretical results.