On the role of delocalization of atoms in melting of crystals and softening of glasses

The interrelation between the delocalization of atoms during melting of crystals and their excitation during softening of glasses is considered. The fraction of excited kinetic units (particles displaced through the critical distance) at the softening temperature is close in order of magnitude to the fraction of delocalized atoms at the melting point. The entropy of glass-liquid quasi-phase transition almost coincides with the entropy of melting of crystals with “loose structures”. It is proposed that the elementary acts of crystal melting and glass softening are of the same origin.