JOURNAL OF THE CHEMICAL SOCIETY OF PAKISTAN, cilt.31, sa.2, ss.207-213, 2009 (SCI-Expanded)
This study gives calculation of the specific heat C-VI of NH4Cl and NH4BrxCl1-x under the Ising model for the transition between the disordered (D) and ferro-ordered O(F) phases in these crystalline systems. Our C-VI values which we calculated for x = 0 and x = 0.04, agree both below and above T-c with the observed C-p data from the literature. Our value of a congruent to 0.1 (T < T-c and T > T-c) is in good agreement with the predicted value of 1/8 (0.125) of a 3D Ising model.