Additive Decomposition of the Physical Components of the Magnetic Coupling from Broken Symmetry Density Functional Theory Calculations

2013 ◽  
Vol 9 (8) ◽  
pp. 3429-3436 ◽  
Author(s):  
Esther Coulaud ◽  
Jean-Paul Malrieu ◽  
Nathalie Guihéry ◽  
Nicolas Ferré
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Magnetic Coupling ◽  
Density Functional Theory Calculations ◽  
Broken Symmetry ◽  
Additive Decomposition ◽  
Functional Theory ◽  
Physical Components

MAGNETIC COUPLING CONSTANTS AND SPIN DENSITY DISTRIBUTIONS FOR CYANO-BRIDGED Gd(III)-Fe(III) AND Gd(III)-Cr(III) COMPOUNDS: BROKEN-SYMMETRY AND DENSITY FUNCTIONAL THEORY CALCULATIONS

2005 ◽  
Vol 19 (15n17) ◽  
pp. 2538-2543 ◽  
Author(s):  
YI QUAN ZHANG ◽  
CHENG LIN LUO ◽  
ZHI YU
Keyword(s):  
Density Functional Theory ◽  
Spin Density ◽  
Spin Polarization ◽  
Density Functional ◽  
Population Analysis ◽  
Magnetic Coupling ◽  
Coupling Constants ◽  
Broken Symmetry ◽  
Functional Theory ◽  
Density Distributions

Magnetic coupling constants J for the complete structures of [ Gd(capro) 2( H 2 O )4 Cr(CN) 6]• H 2 O (capro represents caprolactam) (a) and trans-[ Fe(CN) 4(μ- CN )2 Gd ( H 2 O )4 (bpy) ]•4 H 2 O •1.5 bpy (b) have been calculated using hybrid density functional theory (DFT) B3LYP combined with a modified broken symmetry approach (BS). The calculated J value of -0.24 cm-1 for a is very close to the experimental -0.33 cm-1. They both show the antiferromagnetic interaction between Gd(III) and Cr(III) . For b, although the sign of the calculated J value of 4.24 cm-1 is different from that of the experimental -0.38 cm-1, the two values both show the weak magnetic coupling interaction between Gd(III) and Fe(III) . The spin density distributions are discussed on the basis of Mulliken population analysis. For complexes a and b, both transition metal ( Fe(III) or Cr(III) ) and rare earth Gd(III) display a spin polarization effect on the surrounding atoms, where a counteraction of the opposite polarization effects leads to a low spin density on the bridging ligand C1N1 . For the compounds Gd(III) - Cr(III) (a) and Gd(III) - Fe(III) (b) in the HS states, Cr(III) has stronger spin polarization influence on the bridging atoms than Fe(III) even causing the positive spin population on the bridging atom N1 .

Spin decontamination of broken-symmetry density functional theory calculations: deeper insight and new formulations

2015 ◽  
Vol 17 (22) ◽  
pp. 14375-14382 ◽  
Author(s):  
Nicolas Ferré ◽  
Nathalie Guihéry ◽  
Jean-Paul Malrieu
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Broken Symmetry ◽  
Functional Theory ◽  
Physically Based

This work proposes rigorous and physically based spin decontamination factors for broken-symmetry treatments of diradicals.

Is a Non-Transition Element Nitride Ferromagnet Ever Achievable? Indication of the N-N Pairing Instability

2006 ◽  
Vol 71 (11-12) ◽  
pp. 1525-1531 ◽  
Author(s):  
Wojciech Grochala
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transition Element ◽  
Density Functional Theory Calculations ◽  
Functional Theory

The enthalpy of four polymorphs of CaN has been scrutinized at 0 and 100 GPa using density functional theory calculations. It is shown that structures of diamagnetic calcium diazenide (Ca2N2) are preferred over the cubic ferromagnetic polymorph (CaN) postulated before, both at 0 and 100 GPa.

scholarly journals Tensor-structured algorithm for reduced-order scaling large-scale Kohn–Sham density functional theory calculations

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Chih-Chuen Lin ◽  
Phani Motamarri ◽  
Vikram Gavini
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Large Scale ◽  
Density Functional Theory Calculations ◽  
System Size ◽  
Real Space ◽  
Functional Theory ◽  
Reduced Order ◽  
Separable Approximation ◽  
Tensor Basis

AbstractWe present a tensor-structured algorithm for efficient large-scale density functional theory (DFT) calculations by constructing a Tucker tensor basis that is adapted to the Kohn–Sham Hamiltonian and localized in real-space. The proposed approach uses an additive separable approximation to the Kohn–Sham Hamiltonian and an L1 localization technique to generate the 1-D localized functions that constitute the Tucker tensor basis. Numerical results show that the resulting Tucker tensor basis exhibits exponential convergence in the ground-state energy with increasing Tucker rank. Further, the proposed tensor-structured algorithm demonstrated sub-quadratic scaling with system-size for both systems with and without a gap, and involving many thousands of atoms. This reduced-order scaling has also resulted in the proposed approach outperforming plane-wave DFT implementation for systems beyond 2000 electrons.

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