Potential Energy Curves in Rare Gas Interactions

Potential energy curves describe how the interaction energy between a pair of rare gas atoms varies with their separation. Owing to their closed‐shell electronic structure, noble gases exhibit no permanent dipole moment or conventional chemical bonding; instead, their interactions arise from the delicate balance of attractive dispersion forces and repulsive Pauli exchange. Accurate curves are fundamental to modelling gas‐phase thermodynamics, condensed‐phase properties and spectroscopic phenomena such as collision‐induced absorption. Recent advances have combined high‐level quantum‐mechanical calculations with refined empirical functions to achieve sub‐kiloJoule‐per‐mole accuracy in the well depth and equilibrium distance of noble‐gas dimers. These improvements underpin reliable prediction of virial coefficients, transport properties and phase behaviour, and are essential for understanding noble‐gas mixtures in planetary atmospheres, cryogenic technology and fundamental studies of van der Waals complexes.

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Potential Energy Curves in Rare Gas Interactions publication trend

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Technical terms

Potential energy curve: A plot of interaction energy versus interatomic separation for a diatomic pair.

Dispersion forces: Attractive van der Waals interactions arising from instantaneous correlated fluctuations in electron density.

Pauli repulsion: Short-range repulsive force due to overlap of closed electronic shells enforcing the Pauli exclusion principle.

Well depth (De): The energy minimum on a potential energy curve, indicating interaction strength at equilibrium separation.

Equilibrium distance (Re): The interatomic separation corresponding to the minimum energy on the potential energy curve.

Combination rule: A mathematical scheme to derive heteronuclear interaction parameters from homonuclear ones.

Collision-induced absorption: Spectroscopic absorption arising when otherwise non-polar gas pairs acquire transient dipoles during collisions.

References

1. Impact of Combination Rules, Level of Theory, and Potential Function on the Modeling of Gas- and Condensed-Phase Properties of Noble Gases. Journal of Chemical Theory and Computation (2024).
2. Collision-induced absorption in Ar-Xe: a comparative study of empirical and ab initio interaction potentials and electric dipole moments. Journal of Quantitative Spectroscopy and Radiative Transfer (2022).