Towards accurate estimates of the spin-state energetics of spin-crossover complexes within density functional theory: a comparative case study of cobalt(ii) complexes

2013 ◽  
Vol 15 (11) ◽  
pp. 3752 ◽  
Author(s):  
Alfredo Vargas ◽  
Itana Krivokapic ◽  
Andreas Hauser ◽  
Latévi Max Lawson Daku
Keyword(s):  
Density Functional Theory ◽  
Spin State ◽  
Density Functional ◽  
Spin Crossover ◽  
Comparative Case Study ◽  
Functional Theory ◽  
Spin Crossover Complexes

Assessing the Calculation of Exchange Coupling Constants and Spin Crossover Gaps Using the Approximate Projection Model to Improve Density Function Calculations

2019 ◽  
Author(s):  
Xianghai Sheng ◽  
Lee Thompson ◽  
Hrant Hratchian
Keyword(s):  
Density Functional Theory ◽  
Exchange Coupling ◽  
Density Functional ◽  
Spin Crossover ◽  
Coupling Constants ◽  
Spin Projection ◽  
Coupling Constant ◽  
Projection Model ◽  
Functional Theory

This work evaluates the quality of exchange coupling constant and spin crossover gap calculations using density functional theory corrected by the Approximate Projection model. Results show that improvements using the Approximate Projection model range from modest to significant. This study demonstrates that, at least for the class of systems examined here, spin-projection generally improves the quality of density functional theory calculations of J-coupling constants and spin crossover gaps. Furthermore, it is shown that spin-projection can be important for both geometry optimization and energy evaluations. The Approximate Project model provides an affordable and practical approach for effectively correcting spin-contamination errors in molecular exchange coupling constant and spin crossover gap calculations.

scholarly journals Integrating Density Functional Theory Modeling with Experimental Data to Understand and Predict Sorption Reactions: Exchange of Salicylate for Phosphate on Goethite

Soil Systems ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 27 ◽  
Author(s):  
James D. Kubicki ◽  
Tsutomu Ohno
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Mineral Water ◽  
Surface Complexes ◽  
Functional Theory ◽  
Complex Models ◽  
Mechanical Approach ◽  
Plant Exudates ◽  
Quantum Mechanical Approach

Density functional theory (DFT) calculations are a quantum mechanical approach that can be used to model chemical reactions on an atomistic scale. DFT provides predictions on structures, thermodynamics, spectroscopic parameters and kinetics that can be compared against experimentally determined data. This paper is a primer on the basics of utilizing DFT for applications in mineral-water interfaces. In our case-study, we use DFT to model the surface complexes of phosphate and salicylate adsorbed onto the (101) and (210) surfaces of α-FeOOH (goethite), as an example of combining DFT and experiment. These three components are important in the phosphorus-organic matter interactions in soils, and by comparing the energies of the two surface complexes, the exchange energy of salicylate for phosphate onto goethite can be estimated. The structures of the surface complexes are predicted and the resulting vibrational frequencies calculated based on these structures are compared to previous observations. Upon verification of reasonable surface complex models, the potential energy of exchanging salicylate for phosphate is calculated and shown to be significantly exothermic. This model result is consistent with observations of plant exudates, such as salicylate freeing adsorbed phosphate in soils under P-limited conditions.

The one-electron self-interaction error in 74 density functional approximations: a case study on hydrogenic mono- and dinuclear systems

2020 ◽  
Vol 22 (28) ◽  
pp. 15805-15830 ◽  
Author(s):  
Dale R. Lonsdale ◽  
Lars Goerigk
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Model Systems ◽  
Electron Model ◽  
Functional Theory ◽  
The One

The one-electron self-interaction error (SIE) is analysed for 74 Density Functional Theory (DFT) approximations in a series of novel one-electron model systems revealing new aspects of the SIE that should be considered in future DFT developments.

Sign in / Sign up

Export Citation Format

Share Document