  A method of statistical description of thermodynamic properties of
nanocrystals is developed. It is established that size-dependent quantization
of vibrational modes results in formation of excess pressure of the phonon gas
acting outwards the crystal. Based on the concept of the phonon gas pressure,
size dependence of thermodynamic properties of nanocrystals was described, and
size influence on a shift of a phase transformation temperature was explained.
