Three-Body Contribution to Binding Energy of Solid Argon and Analysis of Crystal Structure

The binding energy of solid argon has been computed using a symmetry-adapted perturbation theory three-body potential. This energy equals -7752.9J/mol and agrees well with the experimental value of -7726±13J/mol. The fcc structure is favored over the hcp structure by 0.01%, in agreement with experimental observations. In accord with an early suggestion of Jansen [Adv. Quantum Chem. 2, 119 (1965)], inclusion of nonadditive exchange contributions were found to be necessary to understand the preferred crystal structure and for accurate computation of the binding energy.