Electronic and structural properties of elemental copper: A pseudopotential–local-orbital calculation

We have examined the electronic and structural properties of elemental copper using pseudopotentials and a local-orbital basis consisting of Gaussians. We find we can use a much weaker ionic pseudopotential to describe accurately the measured band structure, cohesive energy, lattice constant, and compressibility of copper than previous pseudopotential work. Our potential should be more amenable than existing ones to momentum-space evaluations of the total crystalline energy. In addition, we have examined the equation of state for copper in both the fcc and bcc structures. Unlike a recent pseudopotential--mixed-basis calculation, we find that the energy-versus-volume curve for copper in the bcc structure does not exhibit a double minimum.