Violation of the Equipartition Theorem for Thermally Insulated Clusters of Atoms with Different Masses

TL;DR

This paper derives a new expression for calculating kinetic energies in thermally insulated atomic clusters with different masses, revealing violations of the equipartition theorem, supported by numerical simulations of a C8H8 cubane.

Contribution

It introduces a generalized formula for microcanonical averages in multi-mass atomic clusters and demonstrates its validity through numerical simulation.

Findings

The equipartition theorem does not hold in thermally insulated atomic clusters with different masses.

Numerical simulations of C8H8 cubane support the derived expression.

The new formula accurately predicts kinetic energies in isolated multi-atom systems.

Abstract

An expression is derived for calculating microcanonical-ensemble averages of the kinetic energies of atoms of different types in clusters isolated from the environment. This expression is a natural generalization of the solution to the problem of hard spheres with different masses to a system with a many-particle interatomic interaction potential. The dynamics of a C8H8 cubane is simulated numerically. The data on the numerical simulation confirm the validity of the results obtained.