How well does the Lennard-Jones potential represent the thermodynamic properties of noble gases?

Abstract

<p>The Lennard-Jones potential as well as its truncated and shifted (<i>r</i>_c = 2.5σ) variant are applied to the noble gases neon, argon, krypton, and xenon. These models are comprehensively compared with the currently available experimental knowledge in terms of vapour pressure, saturated liquid density, as well as thermodynamic properties from the single phase fluid regions including density, speed of sound, and isobaric heat capacity data. The expectation that these potentials exhibit a more modest performance for neon as compared to argon, krypton, and xenon due to increasing quantum effects does not seem to hold for the investigated properties. On the other hand, the assumption that the truncated and shifted (<i>r</i>_c = 2.5σ) variant of the Lennard-Jones potential may have shortcomings because the long range interactions are entirely neglected beyond the cut-off radius <i>r</i>_c, are supported by the present findings for the properties from the single phase fluid regions. For vapour pressure and saturated liquid density such a clear assessment cannot be made.</p