New Kinetic Theory and New Equations for Lattice and Electronic Heat Capacities, Enthalpies and Entropies of Solids: Application to Tungsten

A. Bozdoğan Yıldız Technical University, Department of Chemistry, Davutpaşa, 34220 Esenler, Istanbul, Turkey

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New equations for heat capacities, entropies and enthalpies were applied to the experimental constant volume and constant pressure heat capacity data of tungsten. The heat capacity CPmax was predicted to be 24.96 J/moK at 400 K. The temperatures ΘpV and ΘpP were found to be 78.5 K. The relationships between dimension and ΘpV and Debye temperature were given. Tungsten shows the dimensionality crossover from 3 to 2 at about 80 K. Temperature dependences of Debye temperature, ΘpV and ΘpP and non-monotonic behavior were discussed. The heat capacity and entropy values predicted by the proposed models were compared with the values predicted by the Debye models. The results have shown that the proposed models fit the data better than the Debye models. The enthalpy values predicted by the proposed models were compared with the values predicted by the polynomial model and good fitting was obtained. The proposed models have shown that the constant pressure heat capacity data can be used to calculate enthalpies, entropies and heat capacities of tungsten.

DOI:10.12693/APhysPolA.134.213 topics: heat capacity, entropy and enthalpy, dimension, tungsten