scholarly journals Strong Correlations in Density-Functional Theory: A Model of Spin-Charge and Spin–Orbital Separations

2014 ◽  
Vol 10 (9) ◽  
pp. 3641-3646 ◽  
Author(s):  
Daniel Vieira
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Strong Correlations ◽  
Spin Orbital ◽  
Functional Theory

Density Functional Theory (DFT) Calculations of Indirect Nuclear Spin-Spin Coupling Constants 1J(31P, 13C) in λ3-Phosphaalkynes

2003 ◽  
Vol 58 (11) ◽  
pp. 1041-1044 ◽  
Author(s):  
Bernd Wrackmeyer
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Strong Dependence ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Positive Sign ◽  
Spin Orbital ◽  
Functional Theory ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

The calculation of the spin-spin coupling constants 1J(31P,≡13C) of λ3-1-phosphaalkynes P≡C-R (R = H, Me, tBu, Ph, SiMe3 and NMe2) using density functional theory (DFT) have revealed a positive sign of this coupling constant in agreement with the experiment for P≡C-tBu. The calculations have shown that the Fermi contact (FC) contribution to this coupling is negative [in contrast to FC for 1J(14N,≡13C) in the corresponding nitriles], and that the positive sign of 1J(31P,≡13C) is the result of significant contributions arising from spin-dipole (SD) and paramagnetic spin-orbital (PSO) terms. Coupling constants were also calculated for some representative λ3-phosphorus compounds containing two- and three-coordinate phosphorus, indicating the strong dependence of the FC term on the geometry at the phosphorus atom.

scholarly journals Range-Separation and the Multiple Radii Functional Approximation Inspired by the Strongly Interacting Limit of Density Functional Theory

2019 ◽  
Author(s):  
Stefan Vuckovic ◽  
Tim Gould
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Approximate Theory ◽  
Exact Results ◽  
Strong Correlations ◽  
Functional Theory ◽  
One Dimensional ◽  
Strongly Interacting ◽  
Correlation Problem ◽  
Exactly Solvable

The strongly-interacting limit of density functional theory has attracted considerable attention recently due to its ability to deal with the difficult strong correlation problem. Recent work [JPCL 8, 2799-2805 (2017)] introduced the "multiple radii functional" (MRF) approximation, inspired by this limit, which is designed to work well for strong correlations between dissociated fragments. Here, we analyse the MRF in exactly solvable one-dimensional molecules, to uncover how it matches, and deviates from, exact results; and use range-separation of the Coulomb potential in both exact and approximate theory to explore how this varies in space. Our work opens a path to new approximations incorporating the MRF, amongst other ingredients.<br><br>

scholarly journals Range-Separation and the Multiple Radii Functional Approximation Inspired by the Strongly Interacting Limit of Density Functional Theory

2019 ◽  
Author(s):  
Stefan Vuckovic ◽  
Tim Gould
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Approximate Theory ◽  
Exact Results ◽  
Strong Correlations ◽  
Functional Theory ◽  
One Dimensional ◽  
Strongly Interacting ◽  
Correlation Problem ◽  
Exactly Solvable

The strongly-interacting limit of density functional theory has attracted considerable attention recently due to its ability to deal with the difficult strong correlation problem. Recent work [JPCL 8, 2799-2805 (2017)] introduced the "multiple radii functional" (MRF) approximation, inspired by this limit, which is designed to work well for strong correlations between dissociated fragments. Here, we analyse the MRF in exactly solvable one-dimensional molecules, to uncover how it matches, and deviates from, exact results; and use range-separation of the Coulomb potential in both exact and approximate theory to explore how this varies in space. Our work opens a path to new approximations incorporating the MRF, amongst other ingredients.<br><br>

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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