Efficient isoparametric integration over arbitrary space-filling Voronoi polyhedra for electronic structure calculations

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2011-07-15
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Alam, Aftab
Khan, Suffian
Wilson, Brian
Johnson, Duane
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Johnson, Duane
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Ames National Laboratory
Abstract

A numerically efficient, accurate, and easily implemented integration scheme over convex Voronoi polyhedra (VP) is presented for use in ab initio electronic-structure calculations. We combine a weighted Voronoi tessellation with isoparametric integration via Gauss-Legendre quadratures to provide rapidly convergent VP integrals for a variety of integrands, including those with a Coulomb singularity. We showcase the capability of our approach by first applying it to an analytic charge-density model achieving machine-precision accuracy with expected convergence properties in milliseconds. For contrast, we compare our results to those using shape-functions and show our approach is greater than 105 times faster and 107 times more accurate. A weighted Voronoi tessellation also allows for a physics-based partitioning of space that guarantees convex, space-filling VP while reflecting accurate atomic size and site charges, as we show within KKR methods applied to Fe-Pd alloys.

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This article is from Phys. Rev. B 84, 045105 (2011), doi:10.1103/PhysRevB.84.045105. Posted with permission.

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Sat Jan 01 00:00:00 UTC 2011
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