Order-to-disorder phase transitions in nanometre-sized particles

A quasi-chemical approach is developed to qualitatively describe the thermodynamics of order-to-disorder phase transitions in nanometre-sized particles. Thermodynamic quantities are shown to depend on the number of nearest neighbours of surface atoms and on the particle size. In particular, the critical temperature of transition is predicted to change linearly with the reciprocal of the particle radius. The result is supported by available literature data.