  In a large variety of ideal crystals we found that when rapidly migrating
atoms squash or annihilate a neighbouring vacancy and produce a disordered
cluster, the heat of migration stored in the system exceeds the enthalpy
increase required for the coordinating atoms of the vacancy to form a liquid
phase, i.e. the liquid phase nucleates from vacancies. Furthermore volumetric
analysis supports this well. This vacancy-decomposition model provides
quantitative information on the melting point, the latent heat and the volume
change upon melting and hence clarifies the mechanism of melting.
