Dependence of the crystal-liquid phase transition temperature on the size and shape of a nanocrystal

The dependence of the crystal-liquid phase transition (melting) temperature Tm on the size and shape of a nanocrystal with a free surface has been studied proceeding from the Lindemann criterion. It is shown that, with neglect of the surface pressure, the Tm value decreases with a reduction in the isomorphous nanocrystal size. The greater the nanocrystal shape deviation from cubic, the more pronounced the size dependence of Tm. With allowance for the surface pressure, the Tm value increases with decreasing nanocrystal size if the arising pressure compresses the crystal. If the surface pressure produces an extension of the crystal, the decrease in Tm with decreasing size becomes more pronounced. The surface pressure can both suppress and enhance the size-dependent Tm variations.