In the paper there are investigated the basic reference systems in the statistical thermodynamics of liquids from the point of view of the expediency of their use in thermodynamic perturbation theory. A quantum hard-sphere system widely used in this field is considered. As is known, the Wigner-Uhlenbeck-Gropper expansion is not suitable for nonanalytic potentials. Therefore, a special expansion into a series method is used in this work, the efficiency of which has been verified by the example of argon and helium 4.
05.30.Ch Quantum ensemble theory
05.70.Ce Thermodynamic functions and equations of state
$^1$Department of Quantum Statistics and Field Theory, Faculty of Physics, M.V.Lomonosov Moscow State University
Science News of the Faculty of Physics, Lomonosov Moscow State University
This new information publication, which is intended to convey to the staff, students and graduate students, faculty colleagues and partners of the main achievements of scientists and scientific information on the events in the life of university physicists.