scholarly journals Quantifying confidence in density functional theory predictions of magnetic ground states

2017 ◽  
Vol 96 (13) ◽  
Author(s):  
Gregory Houchins ◽  
Venkatasubramanian Viswanathan
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ground States ◽  
Functional Theory

scholarly journals Ensemble Density Functional Theory Reloaded

2020 ◽  
Author(s):  
Tim Gould ◽  
Gianluca Stefanucci ◽  
Stefano Pittalis
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Low Cost ◽  
Ground States ◽  
Exchange Energy ◽  
Functional Theory ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem

Density functional theory can be generalized to mixtures of ground and excited states, for the purpose of determining energies of excitations using low-cost density functional approximations. Adapting approximations originally developed for ground states to work in the new setting would fast-forward progress enormously. But, previous attempts have stumbled on daunting fundamental issues. Here we show that these issues can be prevented from the outset, by using a fluctuation dissipation theorem (FDT) to dictate key functionals. We thereby show that existing exchange energy approximations are readily adapted to excited states, when combined with a rigorous exact Hartree term that is different in form from its ground state counterpart, and counterparts based on ensemble ansatze. Applying the FDT to correlation energies also provides insights into ground state-like and ensemble-only correlations. We thus provide a comprehensive and versatile framework for ensemble density functional approximations.<br><br>

scholarly journals Ensemblization of density-functional theory: Insight from the fluctuation-dissipation theorem

2020 ◽  
Author(s):  
Tim Gould ◽  
Gianluca Stefanucci ◽  
Stefano Pittalis
Keyword(s):  
Density Functional Theory ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Low Cost ◽  
Ground States ◽  
Exchange Energy ◽  
Functional Theory ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem

Density functional theory can be generalized to mixtures of ground and excited states, for the purpose of determining energies of excitations using low-cost density functional approximations. Adapting approximations originally developed for ground states to work in the new setting would fast-forward progress enormously. But, previous attempts have stumbled on daunting fundamental issues. Here we show that these issues can be prevented from the outset, by using a fluctuation dissipation theorem (FDT) to dictate key functionals. We thereby show that existing exchange energy approximations are readily adapted to excited states, when combined with a rigorous exact Hartree term that is different in form from its ground state counterpart, and counterparts based on ensemble ansatze. Applying the FDT to correlation energies also provides insights into ground state-like and ensemble-only correlations. We thus provide a comprehensive and versatile framework for ensemble density functional approximations.

scholarly journals High throughput study on magnetic ground states with Hubbard U corrections in transition metal dihalide monolayers

2020 ◽  
Vol 2 (1) ◽  
pp. 495-501 ◽  
Author(s):  
Xinru Li ◽  
Zeying Zhang ◽  
Hongbin Zhang
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
High Throughput ◽  
Density Functional ◽  
Ground States ◽  
Functional Theory ◽  
Hubbard U ◽  
High Throughput Study

We present a high throughput study of the magnetic ground states for 90 transition metal dihalide monolayers TMX2 using density functional theory based on a collection of Hubbard U values.

A density functional theory study on the structural and electronic properties of PbxSbySez (x + y + z = 2, 3) clusters

2018 ◽  
Vol 32 (03) ◽  
pp. 1850024
Author(s):  
Rengi̇n Peköz ◽  
Şaki̇r Erkoç
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Density Functional ◽  
Ground States ◽  
Density Functional Theory Calculations ◽  
Energy Difference ◽  
Binding Energies ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Scalene Triangle

The structural and electronic properties of neutral ternary PbxSbySez clusters (x + y + z = 2, 3) in their ground states have been explored by means of density functional theory calculations. The geometric structures and binding energies are systematically explored and for the most stable configurations of each cluster type vibrational frequencies, charges on atoms, energy difference between highest occupied and lowest unoccupied molecular orbitals, and the possible dissociations channels have been analyzed. Depending on being binary or ternary cluster and composition, the most energetic structures have singlet, doublet or triplet ground states, and trimers prefer to form isosceles, equilateral or scalene triangle structure.

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