scholarly journals Flexibility of the quasi-non-uniform exchange-correlation approximation

2014 ◽  
Vol 89 (11) ◽  
Author(s):  
H. Levämäki ◽  
M. P. J. Punkkinen ◽  
K. Kokko ◽  
L. Vitos
Keyword(s):  
Exchange Correlation ◽  
Correlation Approximation

A DFT Study of Electronic and Magnetic Properties of Cr2O3 using Spin-Polarized Approach

2018 ◽  
Vol 1 (1) ◽  
pp. 91-96
Author(s):  
Abeer E. Aly ◽  
D. P. Rai
Keyword(s):  
Magnetic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Electronic And Magnetic Properties ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Correlation Approximation

The study of Cr2O3 magneto-electric material, particularly, the profound understanding of its antiferro-magnetic, is vital for its spintronics applications. In this paper, we present a study on electronic and magnetic properties of Cr2O3 crystal using the first-principles calculations based on the density functional theory. For more accurate results, additional Hubbard (U) parameter has been employed to GGA as well. Our calculated results are homogeneous with available experimental measurements. Results show the effects produced by GGA+U method upon the electronic and magnetic features of the material. We prove that, the spherically symmetric GGA+U approach for exchange correlation approximation portray is a superior depiction of electronic and magnetic properties of Cr2O3.

Inelastic scattering at surfaces and interfaces

1986 ◽  
Vol 44 ◽  
pp. 392-393
Author(s):  
R. H. Ritchie ◽  
A. Howie
Keyword(s):  
Inelastic Scattering ◽  
Surface Properties ◽  
Correlation Energy ◽  
Condensed Matter ◽  
Charged Particles ◽  
Condensed Matter Physics ◽  
Optical Phonons ◽  
Exchange Correlation ◽  
Surfaces And Interfaces ◽  
Inelastic Interactions

An important part of condensed matter physics in recent years has involved detailed study of inelastic interactions between swift electrons and condensed matter surfaces. Here we will review some aspects of such interactions.Surface excitations have long been recognized as dominant in determining the exchange-correlation energy of charged particles outside the surface. Properties of surface and bulk polaritons, plasmons and optical phonons in plane-bounded and spherical systems will be discussed from the viewpoint of semiclassical and quantal dielectric theory. Plasmons at interfaces between dissimilar dielectrics and in superlattice configurations will also be considered.

Exchange-Correlation Energy Densities and Response Potentials: Connection Between Two Definitions and Analytical Model for the Strong-Coupling Limit of a Stretched Bond

2019 ◽  
Author(s):  
S. Giarrusso ◽  
Paola Gori-Giorgi
Keyword(s):  
Density Functional Theory ◽  
Strong Coupling ◽  
Density Functional ◽  
Correlation Energy ◽  
Order Term ◽  
Strong Coupling Limit ◽  
Local Form ◽  
Coupling Constant ◽  
Functional Theory ◽  
Exchange Correlation

We analyze in depth two widely used definitions (from the theory of conditional probablity amplitudes and from the adiabatic connection formalism) of the exchange-correlation energy density and of the response potential of Kohn-Sham density functional theory. We introduce a local form of the coupling-constant-dependent Hohenberg-Kohn functional, showing that the difference between the two definitions is due to a corresponding local first-order term in the coupling constant, which disappears globally (when integrated over all space), but not locally. We also design an analytic representation for the response potential in the strong-coupling limit of density functional theory for a model single stretched bond.<br>

Evaluating Transition Metal Barrier Heights with the Latest DFT Exchange–Correlation Functionals – the MOBH35 Benchmark Dataset

2019 ◽  
Author(s):  
Mark Iron ◽  
Trevor Janes
Keyword(s):  
Transition Metal ◽  
Density Functional ◽  
Computational Cost ◽  
Basis Set ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Barrier Heights ◽  
Complete Basis Set ◽  
Complete Basis Set Limit ◽  
Hybrid Functionals

A new database of transition metal reaction barrier heights – MOBH35 – is presented. Benchmark energies (forward and reverse barriers and reaction energy) are calculated using DLPNO-CCSD(T) extrapolated to the complete basis set limit using a Weizmann1-like scheme. Using these benchmark energies, the performance of a wide selection of density functional theory (DFT) exchange–correlation functionals, including the latest from the Truhlar and Head-Gordon groups, is evaluated. It was found, using the def2-TZVPP basis set, that the ωB97M-V (MAD 1.8 kcal/mol), ωB97X-V (MAD 2.1 kcal/mol) and SCAN0 (MAD 2.1 kcal/mol) hybrid functionals are recommended. The double-hybrid functionals PWPB95 (MAD 1.6 kcal/mol) and B2K-PLYP (MAD 1.8 kcal/mol) did perform slightly better but this has to be balanced by their increased computational cost.

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