Specific heat and frequency shifts for the translational modes in ammonia solid I close to phase transition

The specific heat Cp is correlated to the frequency shifts (1/ν)(∂ν/∂T)p in ammonia solid I close to the melting point. Our calculated Raman frequencies for the translational modes of νT (100 cm−1) and νT (130 cm−1), are used for this correlation for the pressures of 0, 1.93 and 3.07 kbar in this crystalline system. We obtain that the specific heat varied linearly with the frequency shifts for those pressures studied and values of the slope dPm/dT were extracted. The observed behaviour of the ammonia solid I near the melting point is explained on the basis of our spectroscopic modification of the first Pippard relation.