Heat capacity dilational

In analogy with the approach that has been described in the section on the low-temperature heat capacity, the high-temperature heat capacity of the LnXj compounds can be described as the sum of the lattice and excess contributions (eq. (1)). However, whereas at low temperature the lattice heat capacity mainly arises from harmonic vibrations, at high temperatures the effects of anharmonicity of the vibrations, of thermal dilation of the lattice and of thermally... 

For the heat capacity, only the lattice vibration and dilatational contributions could be evaluated from the molecular dynamics calculations. An electronic contribution of Cei(T) = 3.12 X 10 T (J-K -mor ) was added, based on the very low temperature results of de Novion and Costa [1970NOV/COS]. 

Solids absorb heat on melting and, with the notable exception of ice, expand. They evolve heat when they undergo polymorphic transformation to a more stable polymorphic and contract. Consequently, dilatometric (specific volume-temperature) curves bear a close resemblance to calorimetric (enthalpy-temperature) curves. The melting dilation corresponds to the heat of fusion, and the coefficient of cubical expansion, a, corresponds to the specific heat capacity, c. The ratio cja is virtually a constant independent of temperature. 

Water ranks first of all bodies yet known in Ita increasing capacity for heat, at an derated temperature. Between 22 and 82° Fahr. the specific heat of solidified water is 0-505, assuming it to be unity in the liquid state, and if converted into steam the specific heat of the vapor increases with ita state of dilatation. This property contributes in no small degree towards moderating tho rapidity of the transitions from heat to cold, and vies versa, in the atmosphere, owing to the large quantity of heat which is absorbed by or emitted from the water of the ocean, when tho temperature exceeds or falls short of the normal range. 

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