Vacancies in oligomer crystals

The conditions for the existence of supervacancies in oligomer crystals—defects typical of chain systems-are studied. These vacancies are shown to be nucleated when the temperature exceeds a certain critical threshold T _cr. The equilibrium concentration of supervacancies is calculated. Temperature T _cr is found to be the point of the second-order phase transition. The equation relating transition temperature T _cr and chain length is derived.