Determination of the Temperature Dependence of Heat Capacity for Some Molecular Crystals of Nitro Compounds

• Published in: Journal of engineering physics and thermophysics Vol. 91; no. 2; pp. 278 - 287
• Main Authors: Kovalev, Yu. M., Kuropatenko, V. F.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2018; Springer
• Subjects: Classical Mechanics; Complex Systems; Engineering; Engineering Thermodynamics; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Thermodynamics; equation of state; Einstein approximation; Planck constant; Boltzmann constant; molecular crystal; Helmholtz energy; Debye approximation
• ISSN: 1062-0125; 1573-871X
• DOI: 10.1007/s10891-018-1747-6

An analysis of the existing approximations used for describing the dependence of heat capacity at a constant volume on the temperature of a molecular crystal has been carried out. It is shown that the considered Debye and Einstein approximations do not enable one to adequately describe the dependence of heat capacity at a constant volume on the temperature of the molecular crystals of nitro compounds. This inference requires the development of special approximations that would describe both low-frequency and high-frequency parts of the vibrational spectra of molecular crystals. This work presents a universal dependence allowing one to describe the dependence of heat capacity at a constant volume on temperature for a number of molecular crystals of nitro compounds.