A new empirical potential energy function for Ar₂

ABSTRACT

A critical re-analysis of all available spectroscopic and virial coefficient data for Ar₂ has been used to determine an improved empirical analytic potential energy function that has been ‘tuned’ to optimise its agreement with viscosity, diffusion and thermal diffusion data, and whose short-range behaviour is in reasonably good agreement with the most recent ab initio calculations for this system. The recommended Morse/long-range potential function is smooth and differentiable at all distances, and incorporates both the correct theoretically predicted long-range behaviour and the correct limiting short-range functional behaviour. The resulting value of the well depth is cm⁻¹ and the associated equilibrium distance is  r_e = 3.766 (±0.002) Å, while the ⁴⁰Ar s-wave scattering length is −714 Å.

KEYWORDS:

• Ar₂ potential curve
• Ar₂ virial coefficients
• Ar₂ transport coefficients
• empirical analysis

Acknowledgments

This research has been supported by the Natural Sciences and Engineering Research Council of Canada by way of a ‘Discovery’ grant awarded to Robert J. Le Roy.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Natural Sciences and Engineering Research Council of Canada [grant number RPGIN-3929-2014].