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

TL;DR

This paper evaluates the applicability of Debye and Einstein models to describe the heat capacities of various chalcogenides, demonstrating their effectiveness within uncertainties and establishing conditions for their equivalence.

Contribution

It provides a comparative analysis of Debye and Einstein models for heat capacities of chalcogenides, highlighting their conditions for similar results and applicability.

Findings

Models describe heat capacities within uncertainties.

Debye and Einstein models give similar results under certain conditions.

Single equations can describe heat capacities as functions of reduced temperature.

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.