Lattice dynamics, thermal properties

Dynamic statistical sum and temperature of an isolated body

N. N. Gorobey, A. S. Lukyanenko

Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia

Abstract: Analysis of the thermoelastic Joule–Thomson effect indicates the need to separate the total energy of an isolated body into two components – the quasi-static energy of elastic deformation, which includes thermal expansion, and the energy of atomic vibrations. A dynamic statistical sum is proposed as an analysis tool, which allows one to calculate the average values of observed values over a long period of time, including in the presence of external time-dependent forces. Based on the fact that, in accordance with the ergodic hypothesis, the limit of the dynamic statistical distribution for an isolated body is the microcanonical distribution, and for its subsystems the canonical Gibbs distribution, a definition of the temperature of an isolated body is proposed. The energy balance in the thermoelastic effect is in full accordance with the first law of thermodynamics for an isolated body.

Keywords: anharmonicity, stochasticity, deformation, energy, temperature.

Received: 05.03.2024
Revised: 05.03.2024
Accepted: 07.04.2024

DOI: 10.61011/FTT.2024.05.58087.41

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