Barker-Fisher-Watts potential

A comparison of the pairwise contribution to the Barker-Fisher-Watts potential with the Lennard-Jones potential for argon is shown in Figure 4.38. 

A notable example of a potential that does include many-body terms is the Barker-Fisher-Watts potential for argon, which combines a pairwise potential with an Axilrod-Teller triple... 

Comparison of the Lennard-]ones potential for argon with the Barker-Fisher-Watts pair potential kg is .mann s constant. 

All isothermal calculations discussed here employ Lennard-Jones potential functions and, unless otherwise stated, simulate free-boundary conditions. The neglect of three-particle interactions for a similar (Barker-Fisher-Watts) isolated pair potential has been shown to produce effects that are quite small for Ar systems. For clusters of more than three particles, the third-order potential energy terms 3 increase as the number of three-particle interactions increases. In the limit of zero temperature, where the third-order effects are most prevalent, 3 of the 13-particle Ar cluster (although already 60% of its bulk value) is less than 4.5% of the cluster s total potential energy. For a five-particle Ar cluster, 3 is less than 3% of the total potential energy. 

Fic. 6.S. The surface tension of argon (1), and its representation by a Lennard-Jones potential (2), by the pair potential of Barker, Fisher, and Watts (3al, and by this potential with a three-body correction (3b). 

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