Strong correlation in density functional theory: general discussion

2020 ◽  
Vol 224 ◽  
pp. 373-381
Author(s):  
Emmanuel Fromager ◽  
Nikitas Gidopoulos ◽  
Paola Gori-Giorgi ◽  
Trygve Helgaker ◽  
Pierre-François Loos ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Functional Theory

Electronic or steric effects: Detailed DFT investigations of titanium amino based Kaminsky type olefin catalysts

2018 ◽  
Author(s):  
Jörg Saßmannshausen
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Steric Effects ◽  
Aryl Group ◽  
Functional Theory

We report detailed Density Functional Theory (DFT) investigations of a series of structurally similar titanium (IV) chelating σ-aryl catalysts. Particular attention was paid to the electronic charges of the Ti, C ipso of the substituted aryl group and the benzylic CH<sub>2</sub> and C<i><sub>ipso</sub></i> atoms. The Bader and NBO derived charges were compared with the recently reported polymerisation results by Chan. We found a strong correlation between the relative energies of one of the computed isomers and the activity of the catalyst. Neither NBO nor Bader charges could be convincingly correlated to the observed activity.

Fully Nonlocal Functionals Along the Adiabatic Connection of Density Functional Theory

2019 ◽  
Author(s):  
Stefan Vuckovic
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Effects ◽  
Functional Theory ◽  
Strongly Interacting ◽  
Kinetic Component ◽  
Exact Exchange ◽  
New Framework

Inspired by the exact form of the strongly interacting limit of density functional theory, Vuckovic and Gori Giorgi have recently proposed [J. Phys. Chem. Lett. 2017, 8, 2799] the multiple radii functional (MRF), a new framework for the construction of exchange-correlation (xc) energy approximations able to describe strong correlation electronic effects. To facilitate the construction of improved approximations based on the MRF functional, in the present work we use reverse engineering strategies to reveal the forms of the MRF functional which reproduce the exact xc functional for small atoms. We also develop a procedure that allows the MRF functional to be built on the top of exact exchange. Using the adiabatic connection representation of the xc functional, we also investigate routes for the construction of the correlation functional by combining information from the physical, weakly and strongly interacting regimes. We highlight the advantages of this approach over previous adiabatic connection-based approaches for the treatment of strong correlation and discuss how it can be used for recovering the presently missing kinetic component of the correlation energy in the MRF framework.<br> <pre><br></pre>

Effect of carbon content and electronic strong correlation on the mechanical and thermodynamic properties of ytterbium carbides

RSC Advances ◽  
2015 ◽  
Vol 5 (125) ◽  
pp. 103082-103090 ◽  
Author(s):  
Wei Dong ◽  
Chao Zhang ◽  
Hong Jiang ◽  
Yue-Hua Su ◽  
Zhen-Hong Dai
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Carbon Content ◽  
Strong Correlation ◽  
Density Functional ◽  
Functional Theory

The mechanical and thermodynamic properties of four ytterbium carbides with increasing carbon content have been examined usingab initiocalculations based on density functional theory.

scholarly journals Fully Nonlocal Functionals Along the Adiabatic Connection of Density Functional Theory

2019 ◽  
Author(s):  
Stefan Vuckovic
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Correlation Energy ◽  
Electronic Effects ◽  
Functional Theory ◽  
Strongly Interacting ◽  
Kinetic Component ◽  
Exact Exchange ◽  
New Framework

Inspired by the exact form of the strongly interacting limit of density functional theory, Vuckovic and Gori Giorgi have recently proposed [J. Phys. Chem. Lett. 2017, 8, 2799] the multiple radii functional (MRF), a new framework for the construction of exchange-correlation (xc) energy approximations able to describe strong correlation electronic effects. To facilitate the construction of improved approximations based on the MRF functional, in the present work we use reverse engineering strategies to reveal the forms of the MRF functional which reproduce the exact xc functional for small atoms. We also develop a procedure that allows the MRF functional to be built on the top of exact exchange. Using the adiabatic connection representation of the xc functional, we also investigate routes for the construction of the correlation functional by combining information from the physical, weakly and strongly interacting regimes. We highlight the advantages of this approach over previous adiabatic connection-based approaches for the treatment of strong correlation and discuss how it can be used for recovering the presently missing kinetic component of the correlation energy in the MRF framework.<br> <pre><br></pre>

scholarly journals Describing strong correlation with fractional-spin correction in density functional theory

2018 ◽  
Vol 115 (39) ◽  
pp. 9678-9683 ◽  
Author(s):  
Neil Qiang Su ◽  
Chen Li ◽  
Weitao Yang
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Low Cost ◽  
Spin Symmetry ◽  
Ionic Species ◽  
Electronic Energy ◽  
Functional Theory ◽  
Fractional Charge ◽  
Fractional Spin

An effective fractional-spin correction is developed to describe static/strong correlation in density functional theory. Combined with the fractional-charge correction from recently developed localized orbital scaling correction (LOSC), a functional, the fractional-spin LOSC (FSLOSC), is proposed. FSLOSC, a correction to commonly used functional approximations, introduces the explicit derivative discontinuity and largely restores the flat-plane behavior of electronic energy at fractional charges and fractional spins. In addition to improving results from conventional functionals for the prediction of ionization potentials, electron affinities, quasiparticle spectra, and reaction barrier heights, FSLOSC properly describes the dissociation of ionic species, single bonds, and multiple bonds without breaking space or spin symmetry and corrects the spurious fractional-charge dissociation of heteroatom molecules of conventional functionals. Thus, FSLOSC demonstrates success in reducing delocalization error and including strong correlation, within low-cost density functional approximation.

Electronic or steric effects: Detailed DFT investigations of titanium amino based Kaminsky type olefin catalysts

2018 ◽  
Author(s):  
Jörg Saßmannshausen
Keyword(s):  
Density Functional Theory ◽  
Strong Correlation ◽  
Density Functional ◽  
Steric Effects ◽  
Aryl Group ◽  
Functional Theory

We report detailed Density Functional Theory (DFT) investigations of a series of structurally similar titanium (IV) chelating σ-aryl catalysts. Particular attention was paid to the electronic charges of the Ti, C ipso of the substituted aryl group and the benzylic CH<sub>2</sub> and C<i><sub>ipso</sub></i> atoms. The Bader and NBO derived charges were compared with the recently reported polymerisation results by Chan. We found a strong correlation between the relative energies of one of the computed isomers and the activity of the catalyst. Neither NBO nor Bader charges could be convincingly correlated to the observed activity.

Doping effects on the geometric and electronic structure of tin clusters

2019 ◽  
Vol 21 (44) ◽  
pp. 24478-24488 ◽  
Author(s):  
Martin Gleditzsch ◽  
Marc Jäger ◽  
Lukáš F. Pašteka ◽  
Armin Shayeghi ◽  
Rolf Schäfer
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Beam Deflection ◽  
Functional Theory ◽  
Doping Effects ◽  
Depth Analysis ◽  
Trajectory Simulations

In depth analysis of doping effects on the geometric and electronic structure of tin clusters via electric beam deflection, numerical trajectory simulations and density functional theory.

What correlation effects are covered by density functional theory?

2000 ◽  
Vol 98 (20) ◽  
pp. 1639-1658 ◽  
Author(s):  
Yuan He, Jurgen Grafenstein, Elfi Kraka,
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Correlation Effects ◽  
Functional Theory
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