Properties of the Ar3 system as a function of the temperature

Abstract

The Ar3 system has been theoretically studied by means of a path integral Monte Carlo (PIMC) approach and a method based on the Boltzmann average of the rovibrational spectra of the trimer. The calculation of these rotational energy levels is made with a method which employs distributed Gaussian functions (DGF) to describe the interparticle distances. Internal energies and specific heats are investigated up to T = 40 K. The PIMC results show some dependence on the degree of restrictions imposed to the displacements of the Ar atoms. The DGF energies display good agreement with the results obtained with the PIMC method within the most restrictive confining radius. The onset of a more diffusive behaviour of the Ar trimer is observed as the temperature increases. At low temperature, quantum mechanical effects are found to be relevant for both energies and radial distributions.