Kinetic-energy density functional: Atoms and shell structure

Garcı́a-González, P.; Alvarellos, J. E.; Chacón, Enrique

doi:10.1103/physreva.54.1897

Cited by 76 publications

(64 citation statements)

References 40 publications

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“…Being the analytic dependence of T S on the electron density a rather academic problem for a long time (see reviews in Refs. 5 and 6), the increasingly rapid development of computational chemistry has turn it an interesting topic, from the proposals of new kinetic energy functionals 7,8,9,10,11,12,13,14,15,16,17,18,19 to the study of the kinetic energy density 20,21 and the application to simple systems. 22,23,24 In order to construct accurate explicit T S [n] function-als we need to get not only good total energies but also the correct density profiles for the ground state of the total energy functional (Eq.…”

Section: Introductionmentioning

confidence: 99%

Kinetic energy density study of some representative semilocal kinetic energy functionals

Garcı́a-Aldea

Alvarellos

2007

The Journal of Chemical Physics

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There is a number of explicit kinetic energy density functionals for non-interacting electron systems that are obtained in terms of the electron density and its derivatives. These semilocal functionals have been widely used in the literature. In this work we present a comparative study of the kinetic energy density of these semilocal functionals, stressing the importance of the local behavior to assess the quality of the functionals. We propose a quality factor that measures the local differences between the usual orbital-based kinetic energy density distributions and the approximated ones, allowing to ensure if the good results obtained for the total kinetic energies with these semilocal functionals are due to their correct local performance or to error cancellations. We have also included contributions coming from the laplacian of the electron density to work with an infinite set of kinetic energy densities. For all the functionals but one we have found that their success in the evaluation of the total kinetic energy are due to global error cancellations, whereas the local behavior of their kinetic energy density becomes worse than that corresponding to the Thomas-Fermi functional.

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Section: Introductionmentioning

confidence: 99%

Kinetic energy density study of some representative semilocal kinetic energy functionals

Garcı́a-Aldea

Alvarellos

2007

The Journal of Chemical Physics

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“…͑13͔͒ and the TFvW functional with the standard 1/9 mixing parameter ͑T TF ͓ ͔ + 1 9 T vW ͓ ͔͒. It has been previously demonstrated that local and semi-local kinetic energy functionals fail to reproduce atomic shell structure, [45][46][47] so these applications present a problematic scenario for the approximate TF and TFvW functionals and a significant challenge for the new embedding protocol. Figure 2 presents the A obtained in these e-DFT calculations.…”

Section: Resultsmentioning

confidence: 99%

Exact nonadditive kinetic potentials for embedded density functional theory

Goodpaster

Ananth

Manby

et al. 2010

The Journal of Chemical Physics

189

214

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We describe an embedded density functional theory ͑DFT͒ protocol in which the nonadditive kinetic energy component of the embedding potential is treated exactly. At each iteration of the Kohn-Sham equations for constrained electron density, the Zhao-Morrison-Parr constrained search method for constructing Kohn-Sham orbitals is combined with the King-Handy expression for the exact kinetic potential. We use this formally exact embedding protocol to calculate ionization energies for a series of three-and four-electron atomic systems, and the results are compared to embedded DFT calculations that utilize the Thomas-Fermi ͑TF͒ and the Thomas-Fermi-von Weisacker approximations to the kinetic energy functional. These calculations illustrate the expected breakdown due to the TF approximation for the nonadditive kinetic potential, with errors of 30%-80% in the calculated ionization energies; by contrast, the exact protocol is found to be accurate and stable. To significantly improve the convergence of the new protocol, we introduce a density-based switching function to map between the exact nonadditive kinetic potential and the TF approximation in the region of the nuclear cusp, and we demonstrate that this approximation has little effect on the accuracy of the calculated ionization energies. Finally, we describe possible extensions of the exact protocol to perform accurate embedded DFT calculations in large systems with strongly overlapping subsystem densities.

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“…However, several nonlocal kinetic energy functionals have been proposed and are considered to be much more accurate than currently available GGA functionals. [64][65][66][67][68] In the next release of eQE, we will include the possibility of using nonlocal nonadditive kinetic energy functionals for improved accuracy.…”

Section: Onc Lusion S a Nd F U Tur E D I R Ect Ionsmentioning

confidence: 99%

eQE: An open‐source density functional embedding theory code for the condensed phase

Genova

Ceresoli

Krishtal

et al. 2017

Int J of Quantum Chemistry

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In this work, we present the main features and algorithmic details of a novel implementation of the frozen density embedding (FDE) formulation of subsystem density functional theory (DFT) that is specifically designed to enable ab initio molecular dynamics (AIMD) simulations of largescale condensed-phase systems containing 1000s of atoms. This code (available at http://eqe. rutgers.edu) has been given the moniker of embedded Quantum ESPRESSO (eQE) as it is a generalization of the open-source Quantum ESPRESSO (QE) suite of programs. The strengths of eQE reside in a hierarchical parallelization scheme that allows for an efficient and fully self-consistent treatment of the electronic structure (via the addition of an additional DIIS extrapolation layer) while simultaneously exploiting the inherent symmetries and periodicities in the system (via sampling of subsystem-specific first Brillouin zones and utilization of subsystem-specific basis sets).While bulk liquids and molecular crystals are two classes of systems that exemplify the utility of the FDE approach (as these systems can be partitioned into weakly interacting subunits), we show that eQE has significantly extended this regime of applicability by outperforming standard semilocal Kohn-Sham DFT (KS-DFT) for large-scale heterogeneous catalysts with quite different layerspecific electronic structure and intrinsic periodicities. eQE features very favorable strong parallel scaling for a model system of bulk liquid water composed of 256 water molecules, which allows for a significant decrease in the overall time to solution when compared to KS-DFT. We show that eQE achieves speedups greater than one order of magnitude (>103) when performing AIMD simulations of such large-scale condensed-phase systems as: (1) | I N T R O D U C T I O NThe Kohn-Sham (KS) formulation of density functional theory (DFT) [1] is currently the most widely employed electronic structure method in the fields of chemistry, physics, and materials science. This is largely due to the fact that KS-DFT employing semilocal exchange-correlation (xc) functionals produces models of remarkable accuracy and predictive capability [2] with a relatively low associated computational cost (that in general Int J Quantum Chem. 2017;117:e25401.

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Kinetic-energy density functional: Atoms and shell structure

Cited by 76 publications

References 40 publications

Kinetic energy density study of some representative semilocal kinetic energy functionals

Kinetic energy density study of some representative semilocal kinetic energy functionals

Exact nonadditive kinetic potentials for embedded density functional theory

eQE: An open‐source density functional embedding theory code for the condensed phase

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