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

ABSTRACT

The Lennard-Jones potential as well as its truncated and shifted (r_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 (r_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 r_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.

KEYWORDS:

• Neon
• argon
• krypton
• xenon
• noble gas
• molecular simulation
• Lennard-Jones
• thermodynamic properties

Acknowledgments

The simulations were carried out on the Hazel Hen cluster at the High Performance Computing Center Stuttgart (HLRS) and on the OCuLUS cluster of the Paderborn Center for Parallel Computing (PC²).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors gratefully acknowledge financial support by Deutsche Forschungsgemeinschaft under grant Nos. VR6/4-2 and SP507/7-2.