Introducing PROFESS 2.0: A parallelized, fully linear scaling program for orbital-free density functional theory calculations

Hung, Linda; Huang, Chen; Shin, Ilgyou; Ho, G. C.; Lignères, Vincent L.; Carter, Emily A.

doi:10.1016/j.cpc.2010.09.001

Cited by 59 publications

(56 citation statements)

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“…We perform OFDFT calculations with our PROFESS 2.0 code 14,62 and KSDFT computations with the ABINIT code. 63 The Perdew-Zunger (PZ) local density approximation (LDA) exchange-correlation (XC) functional is employed in all calculations.…”

Section: Numerical Detailsmentioning

confidence: 99%

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Xia

Carter

2012

Phys. Rev. B

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We propose a density decomposition scheme using a Wang-Govind-Carter (WGC)-based kinetic energy density functional (KEDF) to accurately and efficiently simulate various covalently bonded molecules and materials within orbital free (OF) density functional theory (DFT). By using a local, density-dependent scale function, the total density is decomposed into a highly localized density within covalent bond regions and a flattened delocalized density, with the former described by semilocal KEDFs and the latter treated by the WGC KEDF. The new model predicts reasonable equilibrium volumes, bulk moduli, and phase ordering energies for various semiconductors compared to Kohn-Sham (KS) DFT benchmarks. The decomposition formalism greatly improves numerical stability and accuracy while retaining computational speed compared to simply applying the original WGC KEDF to covalent materials. The surface energy of Si (100) and various diatomic molecule properties can be stably calculated and also agree well with KSDFT benchmarks. This linear scaling, computationally efficient, density-partitioned/multi-KEDF scheme opens the door to large scale simulations of molecules, semiconductors, and insulators with OFDFT.2

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Section: Numerical Detailsmentioning

confidence: 99%

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Xia

Carter

2012

Phys. Rev. B

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“…One result has been the emergence of active research on orbital-free DFT (OFDFT), that is, approximate functionals for the ingredients of the KS free energy, namely the KS kinetic energy (KE) T s , entropy S s , and XC free energy F xc or their ground-state counterparts. Almost all of this effort has been for ground-state OFKE functionals [43][44][45][46] . (Note that most of the OFKE literature invokes the KS separation of the KE in order to use existing E xc approximations consistently.)…”

Section: Introductionmentioning

confidence: 99%

Temperature-dependent behavior of confined many-electron systems in the Hartree-Fock approximation

2012

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Many-electron systems confined at substantial finite temperatures and densities present a major challenge to density functional theory. In particular, there is comparatively little systematic knowledge about the behavior of free-energy density functionals for temperatures and pressures of interest, for example, in the study of warm dense matter. As with ground-state functionals, development of approximate free-energy functionals is faced with significant needs for reliable assessment and calibration data. Here we address, in part, this need for detailed results on well-characterized systems. We present results on a comparatively simple, well-defined, computationally feasible but previously unexplored model, the thermal Hartree-Fock approximation. We discuss the main technical tasks (defining a suitable basis and evaluation of the required matrix elements) and give an illustrative initial application which probes both the content of the model and the solution techniques: a system of eight one-electron atoms with nuclei at fixed, arbitrary positions in a hard-walled box. Even this simple system produces physical behavior different from that produced by simple ground state density functionals used at finite temperature (a common approximation in the study of WDM).

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“…The widely used numerical implementation of orbitalfree DFT is based on a Fourier space formalism using a plane-wave discretization 27,28 . A Fourier space formulation provides an efficient computation of the extended interactions arising in orbital-free DFT-electrostatics and kinetic energy functionals-through Fourier transforms.…”

Section: Introductionmentioning

confidence: 99%

Real-space formulation of orbital-free density functional theory using finite-element discretization: The case for Al, Mg, and Al-Mg intermetallics

2015

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We propose a local real-space formulation for orbital-free DFT with density dependent kinetic energy functionals and a unified variational framework for computing the configurational forces associated with geometry optimization of both internal atomic positions as well as the cell geometry. The proposed real-space formulation, which involves a reformulation of the extended interactions in electrostatic and kinetic energy functionals as local variational problems in auxiliary potential fields, also readily extends to all-electron orbital-free DFT calculations that are employed in warm dense matter calculations. We use the local real-space formulation in conjunction with higher-order finite-element discretization to demonstrate the accuracy of orbital-free DFT and the proposed formalism for the Al-Mg materials system, where we obtain good agreement with Kohn-Sham DFT calculations on a wide range of properties and benchmark calculations. Finally, we investigate the cell-size effects in the electronic structure of point defects, in particular a mono-vacancy in Al. We unambiguously demonstrate that the cell-size effects observed from vacancy formation energies computed using periodic boundary conditions underestimate the extent of the electronic structure perturbations created by the defect. On the contrary, the bulk Dirichlet boundary conditions, accessible only through the proposed real-space formulation, which correspond to an isolated defect embedded in the bulk, show cell-size effects in the defect formation energy that are commensurate with the perturbations in the electronic structure. Our studies suggest that even for a simple defect like a vacancy in Al, we require cell-sizes of ∼ 10 3 atoms for convergence in the electronic structure.

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Introducing PROFESS 2.0: A parallelized, fully linear scaling program for orbital-free density functional theory calculations

Cited by 59 publications

References 0 publications

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Density-decomposed orbital-free density functional theory for covalently bonded molecules and materials

Temperature-dependent behavior of confined many-electron systems in the Hartree-Fock approximation

Real-space formulation of orbital-free density functional theory using finite-element discretization: The case for Al, Mg, and Al-Mg intermetallics

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