where x A and g A are the mole fraction and activity coefficients of component A of the R is the gas constant, T fus and DH fus are the melting point and enthalpy of fusion of the component A, and T is the melting point of the mixture. This equation is written assuming that the contribution from the change in heat capacity upon melting (D fus C p ) is negligible. If the liquid is the result of an ideal mixture, the activity coefficient determined from equation 1, g A = 1, and a liquid that is a DES would have g A < 1.