The authors performed a least-squares fit for crystal potentials derived by APW band structure calculations for monatomic, as well as diatomic, structures. The potential is described by an eighth order polynomial multiplied by an exponential function. The fitted potentials yield eigenvalues, for a variety of k points, within 2-3 mRyd of the first-principles APW results. The authors have also discovered that starting with the fitted potential at a given lattice constant and using the potential in the interstitial region (muffin-tin zero) as a single parameter, the authors are able to accurately reproduce the band structure at another lattice constant. The relationship between the muffin-tin zero and the lattice parameter is very nearly linear. The linear relationship allows the authors to use these modified potentials for 'one-shot' total energy calculations which gives an equilibrium lattice parameter and a bulk modulus in very good agreement with the self-consistent calculations.
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