Assessment of Various Density Functional Theory Methods for Finding Accurate Structures of Actinide Complexes

Kwon, Youngjin; Kim, Hee Kyung; Jeong, Keunhong

doi:10.3390/molecules27051500

Cited by 4 publications

(2 citation statements)

References 39 publications

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“…All of the DFT calculations for reference data were done using the ADF software package (2017 release). − The PBE exchange-correlation functional with ZORA relativistic effect − was employed for each calculation with the large-core triple-ζ basis . Studies have shown that the PBE functional can produce reliable optimized structures and energies for actinide compounds. − The scalar relativistic correction is added because it can reach the order 1–2 eV for the 5f shells. , The combination of the computational method has been thoroughly tested in our previous work on the ThO 2 system …”

Section: Dftb Parameterization For the Th–o Systemmentioning

confidence: 99%

“… 67 Studies have shown that the PBE functional can produce reliable optimized structures and energies for actinide compounds. 68 − 70 The scalar relativistic correction is added because it can reach the order 1–2 eV for the 5f shells. 71 , 72 The combination of the computational method has been thoroughly tested in our previous work on the ThO 2 system.…”

Section: Dftb Parameterization For the Th–o Systemmentioning

confidence: 99%

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Efficient Parameterization of Density Functional Tight-Binding for 5f-Elements: A Th–O Case Study

Liu,

Aguirre,

Cawkwell

et al. 2024

J. Chem. Theory Comput.

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Density functional tight binding (DFTB) models for f-element species are challenging to parametrize owing to the large number of adjustable parameters. The explicit optimization of the terms entering the semiempirical DFTB Hamiltonian related to f orbitals is crucial to generating a reliable parametrization for fblock elements, because they play import roles in bonding interactions. However, since the number of parameters grows quadratically with the number of orbitals, the computational cost for parameter optimization is much more expensive for the felements than for the main group elements. In this work we present a set of efficient approaches for mitigating the hurdle imposed by the large size of the parameter space. A novel groupby-orbital correction functions for two-center bond integrals was developed. With this approach the number of parameters is reduced, and it grows linearly with the number of elements, maintaining the accuracy and the number of parameters, in the case of f elements, by more than 40%. The parameter optimization step was accelerated by means of the mini-batch BFGS method. This method allows parameter optimizations with much larger training sets than other single batch methods. A stochastic optimizer was employed that helped overcome shallow local minima in the objective function. The proposed algorithm was used to parametrize the DFTB Hamiltonian for the Th−O system, which was subsequently applied to the study of ThO 2 nanoparticles. The training set consisted of 6322 unique structures, which is barely feasible with conventional optimization methods. The optimized parameter set, LANL-ThO, displays good agreement with DFT-calculated properties such as energies, forces, and structures for both clusters and bulk ThO 2 . Benefiting from the fewer number of parameters and lower computational costs for objective function evaluations, this new approach shows its potential applications in DFTB parametrization for elements with high angular momentum, which present a challenge to conventional methods.

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Section: Dftb Parameterization For the Th–o Systemmentioning

confidence: 99%

Section: Dftb Parameterization For the Th–o Systemmentioning

confidence: 99%

Efficient Parameterization of Density Functional Tight-Binding for 5f-Elements: A Th–O Case Study

Liu,

Aguirre,

Cawkwell

et al. 2024

J. Chem. Theory Comput.

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Neptunyl Pyrrophen Complexes: Exploring Schiff Base Chemistry with Multidentate Acyclic Ligands and Transuranics

Ducilon,

Nicholas,

Surbella

et al. 2024

Chemistry A European J

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. We report the synthesis, structure, and characterization of two novel neptunyl complexes (NpO2L1 and NpO2L2) constructed from phenylene‐substituted benzyl ester bis(pyrrole)phenylenediamine (named “pyrrophen”) ligands. In both cases, the neptunium center exists in the +6 oxidation state, . As our specific interest is in exploring the chemistry of neptunium compounds containing the linear neptunyl ion (NpO22+) through equatorially coordinating the metal by multidentate organic ligands, we have identified the differences that are likely to cause discrepancy between the two complexes by examining the ions and their coordinative environments through single‐crystal X‐ray crystallography, diffuse reflectance,, and Raman spectroscopy. This is the first time pyrrophen has been utilized in Np chemistry and demonstrates a new platform to study 5f electron participation and coordination.

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Complex Formation in Hyperalkaline Solutions

Kutus,

Sipos

2023

Metal Ions and Complexes in Solution

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Strongly alkaline conditions in aqueous systems may give rise to the formation of novel, so far undiscovered metal complexes, and crystallization from these systems often yields solid materials with peculiar local structures. This is of particular importance from a practical point of view, since the knowledge of the structure and dynamics of these solution species could be the key to understand and to manipulate a large variety of processes, both industrial and geochemical. The current contribution is focused on solution species with ligands as hydroxides, organic molecules with O-donor atoms, or both, which do not form or are undetectable at moderate pH. The possible formation of polynuclear complexes as well as various dehydration products is also discussed. A further important aspect is the characterization of the solids obtained from these systems in terms of both the local symmetry of the complexing ion, i.e. interrelations between solution and the solid structure or the lack of them, and their morphology and/or composition. The general theme of this chapter is that hyperalkalinity, an extreme condition, and unusual chemical events are expected to occur under such conditions.

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Assessment of Various Density Functional Theory Methods for Finding Accurate Structures of Actinide Complexes

Cited by 4 publications

References 39 publications

Efficient Parameterization of Density Functional Tight-Binding for 5f-Elements: A Th–O Case Study

Efficient Parameterization of Density Functional Tight-Binding for 5f-Elements: A Th–O Case Study

Neptunyl Pyrrophen Complexes: Exploring Schiff Base Chemistry with Multidentate Acyclic Ligands and Transuranics

Complex Formation in Hyperalkaline Solutions

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