Editing Argon

[[Image:Lennard-Jones.png|thumb| The Lennard-Jones model for argon.]]
'''Argon''' (Ar) has a mass of 39.948 [[atomic mass units | umas]]. Sadus and Prausnitz have shown that three-body repulsion makes a significant contribution to [[Idealised models#Three-body potentials|three-body interactions]] in the liquid phase
<ref>[http://dx.doi.org/10.1063/1.471172 Richard J. Sadus and J. M. Prausnitz "Three-body interactions in fluids from molecular simulation: Vapor–liquid phase coexistence of argon", Journal of Chemical Physics '''104''' pp. 4784-4787 (1996)]</ref>
(for use of the [[Axilrod-Teller interaction]] see 
<ref>[http://dx.doi.org/10.1103/PhysRevA.45.3659 Phil Attard "Pair-hypernetted-chain closure for three-body potentials: Results for argon with the Axilrod-Teller triple-dipole potential", Physical Review A '''45''' pp. 3659-3669 (1992)]</ref>
<ref>[http://dx.doi.org/10.1103/PhysRevE.55.2707     J. A. Anta, E. Lomba and M. Lombardero "Influence of three-body forces on the gas-liquid coexistence of simple fluids: The phase equilibrium of argon", Physical Review E '''55''' pp. 2707-2712 (1997)]</ref>). 
However, the generic [[Lennard-Jones model]] has been frequently used due to its simplicity; some parameters are quoted in the next section. A specific interatomic potential for Ar has been proposed by Aziz 
<ref>[http://dx.doi.org/10.1063/1.466051  Ronald A. Aziz "A highly accurate interatomic potential for argon", Journal of Chemical Physics '''99''' p. 4518 (1993)]</ref>.

==Thermophysical properties (experimental) ==

{| border="1"
|- 
| Property  <ref>[http://www.webelements.com/argon/physics.html Physical properties of Argon on webelements]  </ref> || Temperature || Pressure
|-
| Triple point || 83.8058 K  || 69 kPa
|-
| Critical point || 150.87 K || 4.898 MPa
|-
| Melting point || 83.80 K ||
|-
| Boiling point ||87.30 K ||
|}

==Lennard-Jones parameters==
The [[Lennard-Jones model |Lennard-Jones]] parameters for liquid argon are listed in the following table:
{| border="1"
|- 
| Authors || <math>\epsilon/k_B</math> (K) || <math>\sigma</math>  (nm)|| Reference
|- 
| Rowley, Nicholson and Parsonage || 119.8   || 0.3405  || <ref>[http://dx.doi.org/10.1016/0021-9991(75)90042-X   L. A. Rowley, D. Nicholson and N. G. Parsonage "Monte Carlo grand canonical ensemble calculation in a gas-liquid transition region for 12-6 Argon", Journal of Computational Physics  '''17''' pp. 401-414 (1975)]</ref>
|- 
|Barker, Fisher and Watts  ||142.095   ||  0.33605  || <ref>[http://dx.doi.org/10.1080/00268977100101821 J. A. Barker,  R. A. Fisher and R. O. Watts "Liquid argon: Monte carlo and molecular dynamics calculations", Molecular Physics '''21''' pp. 657-673 (1971)]</ref>
|- 
| White   || 125.7   ||  0.3345    || <ref>[http://dx.doi.org/10.1063/1.479848 John A. White "Lennard-Jones as a model for argon and test of extended renormalization group calculations", Journal of Chemical Physics '''111''' pp. 9352-9356 (1999)]</ref> parameter set #4
|}
==Radial distribution function==
[[Radial distribution function]]
*[http://dx.doi.org/10.1103/PhysRevA.7.2130 J. L. Yarnell, M. J. Katz, R. G. Wenzel and S. H. Koenig "Structure Factor and Radial Distribution Function for Liquid Argon at 85°K", Physical Review A '''7''' pp. 2130-2144 (1973)]
==Quantum simulations==
*[http://dx.doi.org/10.1080/00268978900100811 J. R. Melrose and K. Singer "An investigation of supercooled Lennard-Jones argon by quantum mechanical and classical Monte Carlo simulation", Molecular Physics '''66''' 1203-1214 (1989)]
==References==
<references/>
'''Related material'''
*[http://dx.doi.org/10.1080/00268976400100611 H. C. Longuet-Higgins and  B. Widom "A rigid sphere model for the melting of argon", Molecular Physics '''8''' pp. 549-556 (1964)]
*[http://dx.doi.org/10.1080/00268976800100721 D. Henderson and J. A. Barker "On the solidification of argon", Molecular Physics '''14''' pp. 587-589 (1968)]
*[http://dx.doi.org/10.1103/PhysRevA.5.2238  F. Lado "Numerical Calculation of the Density Autocorrelation Function for Liquid Argon", Physical Review A '''5''' pp. 2238-2244 (1972)]

[[category: models]]
{{Numeric}}