Effects of dispersion corrections on the theoretical description of bulk metals

Adebayo Adeleke and Erin Johnson

Department of Chemistry, Dalhousie University. 6274 Coburg Road, Halifax, NS, Canada B3H 4R2

Addition of a dispersion correction to standard Kohn-Sham density-functional theory is essential for accurate description of non-covalent intermolecular interactions. Several dispersion-corrected density functionals (DC-DFs) have been shown to exhibit remarkable transferability to hard solids at equilibrium conditions. Despite the considerable body of computational development and studies on DC-DFs, their transferability and performance has not been systematically examined for metallic systems at equilibrium or under isotropic compression. In this study, we extensively examine the ability of selected DC-DFs to describe the equations of state (EOS) for selected elemental metals and intermetallic compounds up to several gigapascals of pressure. EOS-derived properties, such as the equilibrium volume (V0), the bulk modulus (B0), and its pressure derivative (B0'), were then evaluated with and without thermal effects and the results compared with experimental reference data. We also assess the ability of the DC-DFs to predict the phase transition pressures for a set of intermetallic compounds. The results of this study establish the optimum dispersion corrections for accurate description of compressed metals.

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