Buckingham ------Lennard-Jones 12-6 …Lennard-Jones9-6 1 6 r [A] Figure 3.Comparison between a Buckingham-,Lennard-Jones(12-6)and Lennard-Jones (9-6)potential. other commonly known combining rules try to correct this effect,which are Kong24 rules 131 1/6 /12 1 12 e3033 0a6= 213 (9) EaQGGQE38038 (10) and the Waldman-Kagler25 rule 8。+B 1/6 CaaGoaE3303B 0a= (11) 2 Goa In a recent study26 of Ar-Kr and Ar-Ne mixtures,these combining rules were tested and it was found that the Kong rules give the best agreement between simulated and experimental pressure-density curves.An illustration of the different combining rules is shown in Fig.4 for the case of an Ar-Ne mixture. 2.2 Long Range Interactions In the case of long range potentials,like the Coulomb potential,interactions between all particles in the system must be taken into account,if treated without any approximation. 2182 4 6 8 0 1 2 Buckingham Lennard-Jones 12-6 Lennard-Jones 9-6 U [arb. units] r [Å] Figure 3. Comparison between a Buckingham-, Lennard-Jones (12-6) and Lennard-Jones (9-6) potential. other commonly known combining rules try to correct this effect, which are Kong24 rules σαβ =    1 2 13 αασ 12 q αα αασ 6 ααββσ 6 ββ  1 + ββσ 12 ββ αασ 12 αα !1/13  13   1/6 (9) αβ = q αασ 6 ααββσ 6 ββ σ 6 αβ (10) and the Waldman-Kagler25 rule σαβ = σ 6 αα + σ 6 ββ 2 !1/6 , αβ = q αασ6 ααββσ 6 ββ σ 6 αβ (11) In a recent study26 of Ar-Kr and Ar-Ne mixtures, these combining rules were tested and it was found that the Kong rules give the best agreement between simulated and experimental pressure-density curves. An illustration of the different combining rules is shown in Fig.4 for the case of an Ar-Ne mixture. 2.2 Long Range Interactions In the case of long range potentials, like the Coulomb potential, interactions between all particles in the system must be taken into account, if treated without any approximation. 218