| Popis: |
The theory of phase transition of order–disorder type on the molecular-kinetic grounds has been developed for the mixture of fluorofullerenes C60F48, C60F36: transition from the ordered body-centered tetragonal (bct) structure to the disordered face-centered cubic (fcc) structure. The free energies of these phases have been found, their dependence on temperature, composition of material, the degree of ordering and energetic constants has been determined. The temperature of transition between phases has been calculated. The constitution diagram has been constructed and it defines the temperature and concentration areas of bct, fcc phases formation and also the region of realization of both bct and fcc phases. The configuration heat capacity of bct phase and its temperature dependence Cp(T) has been defined. The peak-shaped increase of heat capacity in the neighbourhood of the temperature of phase transition has been estimated and this is in agreement with experimental data. |
