Comments on Model free temperature scaling for heat capacity (V.A. Drebushchak, Journal of Thermal Analysis and Calorimetry, 2017 130, 5)

Abstract

It is shown that the isobaric heat capacity of chalcogenides , , , and can be described by the Debye and Einstein models for the phonon frequency spectrum within their uncertainties; the models give the results for the isochoric heat capacity which are close to each other; the models give the close results for the difference between the isobaric and isochoric heat capacities; the isobaric heat capacities of the isostructural , , and as the functions of the temperature reduced to the Debye (Einstein) temperature are described by single Debay (Einstein) equation for the isobaric heat capacity; the isochoric heat capacities of , , , and (which has another structure than , , and [1]) as the functions of the temperature reduced to the Debye (Einstein) temperature are described by the Debye (Einstein) equation for the isochoric heat capacity. It is shown also that the Debye and Einstein equations for the isochoric heat capacity of , , , and give the same results if the means of the squares of the frequencies of the Debye and Einstein spectra are equal to each other, and the Debye and Einstein equations for the isobaric heat capacity of , , and as the functions of the temperature reduced to the Debye or Einstein temperature give the same results.