Density functional theory (OFT) calculations were performed on the principal intermetallic phases found in Hg-containing dental amalgams, specifically on the γ-(Ag₃Sn), γ₁-(Ag₂Hg₃), γ₂-(Sn₈Hg), η' -(Cu₆Sn₅), ε-(Cu₃Sn), and β-(Ag₄Sn) phases. The computations were carried with a variety of approximations, functionals, cutoffs and pseudopotentials. The calculations were performed using both the Localised and Generalised Gradient Approximation methods (LOA and GGA, respectively), PBE functionals with low-cutoff energies. Based on initial results, subsequent works made use of the superior GGA, more stringent cutoff energies; all at greatly increased computational costs. Results showed that less stringent approximations fail and that the optimal methodology for these intermetallic systems is to use the GGA method with PBE functionals, ultra-soft pseudopotentials with 600eV cutoff energies.
The elastic properties of these phases have also been investigated. The predictions provided reasonable agreements with experimental data available. Although the meanfield model for γ₂ and β failed. Aspects of supercell formation for γ₂-(Sn₈Hg) and β(Ag₄Sn) phase also shown improvement in the structure of these phase thus better agreement with the experimental results available. Density of States and band structure analyses showed all phases to be metallic.