Weeks-Chandler-Andersen perturbation theory

The Weeks-Chandler-Anderson perturbation theory is based on the following decomposition of the intermolecular pair potential (in particular, the Lennard-Jones potential ):

The reference system pair potential is given by (Eq, 4 Ref. 1):

$\Phi _{\rm {repulsive}}(r)=\left\{{\begin{array}{ll}\Phi _{\rm {LJ}}(r)+\epsilon &{\rm {if}}\;r<2^{1/6}\sigma \\0&{\rm {if}}\;r\geq 2^{1/6}\sigma \end{array}}\right.$

and the perturbation potential is given by (Eq, 5 Ref. 1):

$\Phi _{\rm {attractive}}(r)=\left\{{\begin{array}{ll}-\epsilon &{\rm {if}}\;r<2^{1/6}\sigma \\\Phi _{\rm {LJ}}(r)&{\rm {if}}\;r\geq 2^{1/6}\sigma \end{array}}\right.$

Ben-Amotz-Stell reformulation

• Dor Ben-Amotz and George Stell "Reformulation of Weeks-Chandler-Andersen Perturbation Theory Directly in Terms of a Hard-Sphere Reference System", Journal of Physical Chemistry B 108 pp. 6877-6882 (2004)

References

1. John D. Weeks, David Chandler and Hans C. Andersen "Role of Repulsive Forces in Determining the Equilibrium Structure of Simple Liquids", Journal of Chemical Physics 54 pp. 5237-5247 (1971)