1
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Macke E, Timrov I, Marzari N, Ciacchi LC. Orbital-Resolved DFT +U for Molecules and Solids. J Chem Theory Comput 2024; 20:4824-4843. [PMID: 38820347 PMCID: PMC11171274 DOI: 10.1021/acs.jctc.3c01403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/25/2024] [Accepted: 05/02/2024] [Indexed: 06/02/2024]
Abstract
We present an orbital-resolved extension of the Hubbard U correction to density-functional theory (DFT). Compared to the conventional shell-averaged approach, the prediction of energetic, electronic and structural properties is strongly improved, particularly for compounds characterized by both localized and hybridized states in the Hubbard manifold. The numerical values of all Hubbard parameters are readily obtained from linear-response calculations. The relevance of this more refined approach is showcased by its application to bulk solids pyrite (FeS2) and pyrolusite (β-MnO2), as well as to six Fe(II) molecular complexes. Our findings indicate that a careful definition of Hubbard manifolds is indispensable for extending the applicability of DFT+U beyond its current boundaries. The present orbital-resolved scheme aims to provide a computationally undemanding yet accurate tool for electronic structure calculations of charge-transfer insulators, transition-metal (TM) complexes and other compounds displaying significant orbital hybridization.
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Affiliation(s)
- Eric Macke
- Faculty
of Production Engineering, Bremen Center
for Computational Materials Science and MAPEX Center for Materials
and Processes, Hybrid Materials Interfaces Group, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany
| | - Iurii Timrov
- Theory
and Simulation of Materials (THEOS) and National Centre for Computational
Design and Discovery of Novel Materials (MARVEL), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Nicola Marzari
- Theory
and Simulation of Materials (THEOS) and National Centre for Computational
Design and Discovery of Novel Materials (MARVEL), École Polytechnique
Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- University
of Bremen Excellence Chair, Bremen Center
for Computational Materials Science, Am Fallturm 1, 28359 Bremen, Germany
| | - Lucio Colombi Ciacchi
- Faculty
of Production Engineering, Bremen Center
for Computational Materials Science and MAPEX Center for Materials
and Processes, Hybrid Materials Interfaces Group, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany
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2
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Drabik G, Radoń M. Approaching the Complete Basis Set Limit for Spin-State Energetics of Mononuclear First-Row Transition Metal Complexes. J Chem Theory Comput 2024; 20:3199-3217. [PMID: 38574194 PMCID: PMC11044276 DOI: 10.1021/acs.jctc.4c00092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/19/2024] [Accepted: 03/20/2024] [Indexed: 04/06/2024]
Abstract
Convergence to the complete basis set (CBS) limit is analyzed for the problem of spin-state energetics in mononuclear first-row transition metal (TM) complexes by taking under scrutiny a benchmark set of 18 energy differences between spin states for 13 chemically diverse TM complexes. The performance of conventional CCSD(T) and explicitly correlated CCSD(T)-F12a/b calculations in approaching the CCSD(T)/CBS limits is systematically studied. An economic computational protocol is developed based on the CCSD-F12a approximation and (here proposed) modified scaling of the perturbative triples term (T#). This computational protocol recovers the relative spin-state energetics of the benchmark set in excellent agreement with the reference CCSD(T)/CBS limits (mean absolute deviation of 0.4, mean signed deviation of 0.2, and maximum deviation of 0.8 kcal/mol) and enables performing canonical CCSD(T) calculations for mononuclear TM complexes sized up to ca. 50 atoms, which is illustrated by application to heme-related metalloporphyrins. Furthermore, a good transferability of the basis set incompleteness error (BSIE) is demonstrated for spin-state energetics computed using CCSD(T) and other wave function methods (MP2, CASPT2, CASPT2/CC, NEVPT2, and MRCI + Q), which justifies efficient focal-point approximations and simplifies the construction of multimethod benchmark studies.
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Affiliation(s)
- Gabriela Drabik
- Jagiellonian
University, Doctoral School
of Exact and Natural Sciences, Łojasiewicza 11, 30-348 Kraków, Poland
- Jagiellonian
University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków Poland
| | - Mariusz Radoń
- Jagiellonian
University, Faculty of Chemistry, Gronostajowa 2, 30-387, Kraków Poland
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3
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Radoń M. Benchmarks for transition metal spin-state energetics: why and how to employ experimental reference data? Phys Chem Chem Phys 2023; 25:30800-30820. [PMID: 37938035 DOI: 10.1039/d3cp03537a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Accurate prediction of energy differences between alternative spin states of transition metal complexes is essential in computational (bio)inorganic chemistry-for example, in characterization of spin crossover materials and in the theoretical modeling of open-shell reaction mechanisms-but it remains one of the most compelling problems for quantum chemistry methods. A part of this challenge is to obtain reliable reference data for benchmark studies, as even the highest-level applicable methods are known to give divergent results. This Perspective discusses two possible approaches to method benchmarking for spin-state energetics: using either theoretically computed or experiment-derived reference data. With the focus on the latter approach, an extensive general review is provided for the available experimental data of spin-state energetics and their interpretations in the context of benchmark studies, targeting the possibility of back-correcting the vibrational effects and the influence of solvents or crystalline environments. With a growing amount of experience, these effects can be now not only qualitatively understood, but also quantitatively modeled, providing the way to derive nearly chemically accurate estimates of the electronic spin-state gaps to be used as benchmarks and advancing our understanding of the phenomena related to spin states in condensed phases.
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Affiliation(s)
- Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Krakow, Poland.
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4
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Hostaš J, Pérez-Becerra KO, Calaminici P, Barrios-Herrera L, Lourenço MP, Tchagang A, Salahub DR, Köster AM. How important is the amount of exact exchange for spin-state energy ordering in DFT? Case study of molybdenum carbide cluster, Mo4C2. J Chem Phys 2023; 159:184301. [PMID: 37947508 DOI: 10.1063/5.0169409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023] Open
Abstract
Since the form of the exact functional in density functional theory is unknown, we must rely on density functional approximations (DFAs). In the past, very promising results have been reported by combining semi-local DFAs with exact, i.e. Hartree-Fock, exchange. However, the spin-state energy ordering and the predictions of global minima structures are particularly sensitive to the choice of the hybrid functional and to the amount of exact exchange. This has been already qualitatively described for single conformations, reactions, and a limited number of conformations. Here, we have analyzed the mixing of exact exchange in exchange functionals for a set of several hundred isomers of the transition metal carbide, Mo4C2. The analysis of the calculated energies and charges using PBE0-type functional with varying amounts of exact exchange yields the following insights: (1) The sensitivity of spin-energy splitting is strongly correlated with the amount of exact exchange mixing. (2) Spin contamination is exacerbated when correlation is omitted from the exchange-correlation functional. (3) There is not one ideal value for the exact exchange mixing which can be used to parametrize or choose among the functionals. Calculated energies and electronic structures are influenced by exact exchange at a different magnitude within a given distribution; therefore, to extend the application range of hybrid functionals to the full periodic table the spin-energy splitting energies should be investigated.
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Affiliation(s)
- Jiří Hostaš
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Kevin O Pérez-Becerra
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
| | - Patrizia Calaminici
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
| | - Lizandra Barrios-Herrera
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Maicon Pierre Lourenço
- Departamento de Química e Física - Centro de Ciências Exatas, Naturais e da Saúde - CCENS - Universidade Federal do Espírito Santo, 29500-000 Alegre, Espírito Santo, Brazil
| | - Alain Tchagang
- Digital Technologies Research Centre, National Research Council of Canada, 1200 Montréal Road, Ottawa, Ontario K1A 0R6, Canada
| | - Dennis R Salahub
- Department of Chemistry, CMS - Centre for Molecular Simulation, IQST - Institute for Quantum Science and Technology, Quantum Alberta, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Andreas M Köster
- Departamento de Química, Cinvestav, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, CDMX C.P. 07360, Mexico
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5
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de Mendonça JPA, Mariano LA, Devijver E, Jakse N, Poloni R. Artificial Neural Network-Based Density Functional Approach for Adiabatic Energy Differences in Transition Metal Complexes. J Chem Theory Comput 2023; 19:7555-7566. [PMID: 37843492 DOI: 10.1021/acs.jctc.3c00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
During the past decades, approximate Kohn-Sham density functional theory schemes have garnered many successes in computational chemistry and physics, yet the performance in the prediction of spin state energetics is often unsatisfactory. By means of a machine learning approach, an enhanced exchange and correlation functional is developed to describe adiabatic energy differences in transition metal complexes. The functional is based on the computationally efficient revision of the regularized, strongly constrained, and appropriately normed functional and improved by an artificial neural network correction trained over a small data set of electronic densities, atomization energies, and/or spin state energetics. The training process, performed using a bioinspired nongradient-based approach adapted for this work from the particle swarm optimization, is analyzed and discussed extensively. The resulting machine learned meta-generalized gradient approximation functional is shown to outperform most known density functionals in the prediction of adiabatic energy differences for a diverse set of transition metal complexes with varying local coordinations and metal choices.
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Affiliation(s)
| | | | - Emilie Devijver
- Université Grenoble Alpes, CNRS, Grenoble INP, LIG, 38000 Grenoble, France
| | - Noel Jakse
- Université Grenoble Alpes, CNRS, Grenoble INP, SIMaP, 38000 Grenoble, France
| | - Roberta Poloni
- Université Grenoble Alpes, CNRS, Grenoble INP, SIMaP, 38000 Grenoble, France
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6
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Mariano AL, Fernández-Blanco A, Poloni R. Perspective from a Hubbard U-density corrected scheme towards a spin crossover-mediated change in gas affinity. J Chem Phys 2023; 159:154108. [PMID: 37855313 DOI: 10.1063/5.0157971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 09/29/2023] [Indexed: 10/20/2023] Open
Abstract
By employing a recently proposed Hubbard U density-corrected scheme within density functional theory, we provide design principles towards the design of materials exhibiting a spin crossover-assisted gas release. Small molecular fragments are used as case study to identify two main mechanisms behind the change in binding energy upon spin transitions. The feasibility of the proposed mechanism in porous crystals is assessed by correlating the change in binding energy of CO2, CO, N2, and H2, upon spin crossover, with the adiabatic energy difference associated with the spin state change of the square-planar metal in Hofmann-type clathrates (M = Fe, Mn, Ni). A few promising cases are identified for the adsorption of intermediate ligand field strength molecules such as N2 and H2. The latter stands out as the most original result as the strong interaction in low spin, as expected from a Kubas mechanism, results in a large change in binding energy. This work provides a general perspective towards the engineering of open-metal site frameworks exhibiting local environments designed to have a spin crossover upon adsorption of specific gas molecules.
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Affiliation(s)
- A L Mariano
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
| | - A Fernández-Blanco
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
- Institut Laue Langevin, 71 Avenue des Martyrs, CS 20156-38042 Grenoble, France
| | - R Poloni
- SIMaP, Grenoble-INP, CNRS, University of Grenoble Alpes, 38042 Grenoble, France
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7
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Kshirsagar AR, Poloni R. Assessing the Role of the Kohn-Sham Density in the Calculation of the Low-Lying Bethe-Salpeter Excitation Energies. J Phys Chem A 2023; 127:2618-2627. [PMID: 36913525 DOI: 10.1021/acs.jpca.2c07526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
We adopt the GW many-body perturbation theory in conjunction with the Bethe-Salpeter equation (BSE) to compute 57 excitation energies of a set of 37 molecules. By using the PBEh global hybrid functional and a self-consistent scheme on the eigenvalues in GW, we show a strong dependence of the BSE energy on the starting Kohn-Sham (KS) density functional. This arises from both the quasiparticle energies and the spatial localization of the frozen KS orbitals employed to compute the BSE. In order to address the arbitrariness in the mean field choice, we adopt an orbital-tuning scheme where the amount of Fock exchange, α, is tuned to impose that the KS HOMO matches the GW quasiparticle eigenvalue, thus fulfilling the ionization potential theorem in DFT. The performance of the proposed scheme yields excellent results and it is similar to M06-2X and PBEh with α = 75%, consistent with tuned values of α ranging between 60% and 80%.
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Affiliation(s)
| | - Roberta Poloni
- Université Grenoble Alpes, CNRS, Grenoble-INP, SIMaP, 38000 Grenoble, France
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8
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Romero S, Baruah T, Zope RR. Spin-state gaps and self-interaction-corrected density functional approximations: Octahedral Fe(II) complexes as case study. J Chem Phys 2023; 158:054305. [PMID: 36754787 DOI: 10.1063/5.0133999] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Accurate prediction of a spin-state energy difference is crucial for understanding the spin crossover phenomena and is very challenging for density functional approximations, especially for local and semi-local approximations due to delocalization errors. Here, we investigate the effect of the self-interaction error removal from the local spin density approximation (LSDA) and Perdew-Burke-Ernzerhof generalized gradient approximation on the spin-state gaps of Fe(II) complexes with various ligands using recently developed locally scaled self-interaction correction (LSIC) by Zope et al. [J. Chem. Phys. 151, 214108 (2019)]. The LSIC method is exact for one-electron density, recovers the uniform electron gas limit of the underlying functional, and approaches the well-known Perdew-Zunger self-interaction correction (PZSIC) as a particular case when the scaling factor is set to unity. Our results, when compared with reference diffusion Monte Carlo results, show that the PZSIC method significantly overestimates spin-state gaps favoring low spin states for all ligands and does not improve upon density functional approximations. The perturbative LSIC-LSDA using PZSIC densities significantly improves the gaps with a mean absolute error of 0.51 eV but slightly overcorrects for the stronger CO ligands. The quasi-self-consistent LSIC-LSDA, such as coupled-cluster single double and perturbative triple [CCSD(T)], gives a correct sign of spin-state gaps for all ligands with a mean absolute error of 0.56 eV, comparable to that of CCSD(T) (0.49 eV).
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Affiliation(s)
- Selim Romero
- Computational Science Program, The University of Texas at El Paso, El Paso, Texas 79968, USA
| | - Tunna Baruah
- Department of Physics, University of Texas at El Paso, El Paso, Texas 79968, USA
| | - Rajendra R Zope
- Department of Physics, University of Texas at El Paso, El Paso, Texas 79968, USA
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9
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Albavera-Mata A, Trickey SB, Hennig RG. Mean Value Ensemble Hubbard- U Correction for Spin-Crossover Molecules. J Phys Chem Lett 2022; 13:12049-12054. [PMID: 36542415 DOI: 10.1021/acs.jpclett.2c03388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
High-throughput searches for spin-crossover molecules require Hubbard-U corrections to common density functional exchange-correlation (XC) approximations. However, the Ueff values obtained from linear response or based on previous studies overcorrect the spin-crossover energies. We demonstrate that employing a linearly mixed ensemble average spin state as the reference configuration for the linear response calculation of Ueff resolves this issue. Validation on a commonly used set of spin-crossover complexes shows that these ensemble Ueff values consistently are smaller than those calculated directly on a pure spin state, irrespective of whether that be low- or high-spin. Adiabatic crossover energies using this methodology for a generalized gradient approximation XC functional are closer to the expected target energy range than with conventional Ueff values. Based on the observation that the Ueff correction is similar for different complexes that share transition metals with the same oxidation state, we devise a set of recommended averaged Ueff values for high-throughput calculations.
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Affiliation(s)
- Angel Albavera-Mata
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida32611, United States
| | - S B Trickey
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Physics and Department of Chemistry, University of Florida, Gainesville, Florida32611, United States
| | - Richard G Hennig
- Center for Molecular Magnetic Quantum Materials, Quantum Theory Project, University of Florida, Gainesville, Florida32611, United States
- Department of Materials Science and Engineering, University of Florida, Gainesville, Florida32611, United States
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10
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Reimann M, Kaupp M. Spin-State Splittings in 3d Transition-Metal Complexes Revisited: Benchmarking Approximate Methods for Adiabatic Spin-State Energy Differences in Fe(II) Complexes. J Chem Theory Comput 2022; 18:7442-7456. [PMID: 36417564 DOI: 10.1021/acs.jctc.2c00924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The CASPT2+δMRCI composite approach reported in a companion paper has been extended and used to provide high-quality reference data for a series of adiabatic spin gaps (defined as ΔE = Equintet - Esinglet) of [FeIIL6]2+ complexes (L = CNH, CO, NCH, NH3, H2O), either at nonrelativistic level or including scalar relativistic effects. These highly accurate data have been used to evaluate the performance of various more approximate methods. Coupled-cluster theory with singles, doubles, and perturbative triples, CCSD(T), is found to agree well with the new reference data for Werner-type complexes but exhibits larger underestimates by up to 70 kJ/mol for the π-acceptor ligands, due to appreciable static correlation in the low-spin states of these systems. Widely used domain-based local CCSD(T) calculations, DLPNO-CCSD(T), are shown to depend very sensitively on the cutoff values used to construct the localized domains, and standard values are not sufficient. A large number of density functional approximations have been evaluated against the new reference data. The B2PLYP double hybrid gives the smallest deviations, but several functionals from different rungs of the usual ladder hierarchy give mean absolute deviations below 20 kJ/mol. This includes the B97-D semilocal functional, the PBE0* global hybrid with 15% exact-exchange admixture, as well as the local hybrids LH07s-SVWN and LH07t-SVWN. Several further functionals achieve mean absolute errors below 30 kJ/mol (M06L-D4, SSB-D, B97-1-D4, LC-ωPBE-D4, LH12ct-SsirPW92-D4, LH12ct-SsifPW92-D4, LH14t-calPBE-D4, LHJ-HFcal-D4, and several further double hybrids) and thereby also still overall outperform CCSD(T) or uncorrected CASPT2. While exact-exchange admixture is a crucial factor in favoring high-spin states, the present evaluations confirm that other aspects can be important as well. A number of the better-performing functionals underestimate the spin gaps for the π-acceptor ligands but overestimate them for L = NH3, H2O. In contrast to a previous suggestion, non-self-consistent density functional theory (DFT) computations on top of Hartree-Fock orbitals are not a promising path to produce accurate spin gaps in such complexes.
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Affiliation(s)
- Marc Reimann
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Straße des 17. Juni 135, D-10623 Berlin, Germany
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11
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Missana A, Hauser A, Lawson Daku LM. Environmental Control of the Magnetic Behavior of Transition Metal Complexes: Density Functional Theory Study of Zeolite Y Embedded Complexes [M(bpy) 3] 2+@Y (M = Fe 2+, Co 2+). J Phys Chem A 2022; 126:6221-6235. [PMID: 36067495 DOI: 10.1021/acs.jpca.2c05070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using the supramolecular approach developed for the study of the guest-host interactions in the zeolite Y encapsulated [Fe(bpy)3]2+ compound: [Fe(bpy)3]2+@Y (bpy = 2,2'-bipyridine) [Vargas et al., J. Chem. Theory Comput. 2009, 5, 97-115], we apply density functional theory (DFT) to the study of the influence of zeolite Y encapsulation on the structural and energetic properties of [Co(bpy)3]2+ in the low-spin (LS) and high-spin (HS) states, while revisiting [Fe(bpy)3]2+@Y. Although the accurate prediction of the HS-LS energy difference ΔEHLel remains challenging for current DFT methods, they give accurate estimates of its variation Δ(ΔEHLel) in a series of complexes of a given transition metal ion. Therefore, denoting [M(bpy)3]2+@YSM as the supramolecular model of the inclusion compounds, the values of ΔEHLel for the bpy complexes in the gas phase and in the supercage of zeolite Y were determined by combining the DFT estimates of Δ(ΔEHLel) in the series {[M(NCH)6]2+, [M(bpy)3]2+, and [M(bpy)3]2+@YSM}, with accurate CCSD(T) estimates of ΔEHLel in the benchmark complexes [M(NCH)6]2+ (M = Fe, Co) [Lawson Daku et al., J. Chem. Theory Comput., 2012, 8, 4216-4231]. Generalized gradient approximations as well as global and range-separated hybrids were employed. In order to better account for the key role of dispersion, they were also augmented with the semiempirical D2, D3BJ, and D3BJM dispersion corrections when available. The use of the D3BJ and D3BJM corrections led to similar results, and this is only with the use of the D2 scheme that (i) the free and encapsulated [Fe(bpy)3]2+ are correctly predicted as LS species and that (ii) the encapsulation of both complexes translates into a destabilization of their HS state with respect to their LS state. The increase of the HS-LS energy difference is smaller for [Co(bpy)3]2+ than [Fe(bpy)3]2+ because the HS-LS molecular volume difference ΔVHL in [Co(bpy)3]2+ is ∼50% smaller than in [Fe(bpy)3]2+. Periodic DFT calculations performed on crystalline [M(bpy)3]2+@Y show that the employed [M(bpy)3]2+@YSM supramolecular model allows the influence of encapsulation on the geometry and the spin-state energetics of [M(bpy)3]2+ (M = Fe, Co) to be quantitatively captured.
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Affiliation(s)
- Andrea Missana
- Université de Genève, 30 quai Ernest-Ansermet, CH-1211Genève 4, Switzerland
| | - Andreas Hauser
- Université de Genève, 30 quai Ernest-Ansermet, CH-1211Genève 4, Switzerland
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12
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Vitale E, Li Manni G, Alavi A, Kats D. FCIQMC-Tailored Distinguishable Cluster Approach: Open-Shell Systems. J Chem Theory Comput 2022; 18:3427-3437. [PMID: 35522217 PMCID: PMC9202306 DOI: 10.1021/acs.jctc.2c00059] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
A recently proposed
tailored approach based on the distinguishable
cluster method and the stochastic FCI solver, FCIQMC [J. Chem.
Theory Comput. 2020, 16, 5621], is extended to open-shell
molecular systems. The method is employed to calculate spin gaps of
various Fe(II) complexes, including a Fe(II) porphyrin model system.
Both distinguishable cluster and fully relaxed CASSCF natural orbitals
were used in this work as reference for the subsequent tailored distinguishable
cluster calculations. The distinguishable cluster natural orbitals
occupation numbers were also used as an aid to the selection of the
active space. The effect of the active space sizes and of the explicit
correlation correction (F12) onto the predicted spin gaps is investigated.
The tailored distinguishable cluster with singles and doubles yields
consistently more accurate results compared to the tailored coupled
cluster with singles and doubles.
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Affiliation(s)
- Eugenio Vitale
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Giovanni Li Manni
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
| | - Ali Alavi
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany.,Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Daniel Kats
- Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart, Germany
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13
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Finney BA, Chowdhury SR, Kirkvold C, Vlaisavljevich B. CASPT2 molecular geometries of Fe(II) spin-crossover complexes. Phys Chem Chem Phys 2022; 24:1390-1398. [PMID: 34981806 DOI: 10.1039/d1cp04885f] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Using fully internally contracted (FIC)-CASPT2 analytical gradients, geometry optimizations of spin-crossover complexes are reported. This approach is tested on a series of Fe(II) complexes with different sizes, ranging from 13 to 61 atoms. A combination of active space and basis set choices are employed to investigate their role in determining reliable molecular geometries. The reported strategy demonstrates that a wave function-based level of theory can be used to optimize the geometries of metal complexes in reasonable times and enables one to treat the molecular geometry and electronic structure of the complexes using the same level of theory. For a series of smaller Fe(II) SCO complexes, strong field ligands in the LS state result in geometries with the largest differences between DFT and CASPT2; however, good agreement overall is observed between DFT and CASPT2. For the larger complexes, moderate sized basis sets yield geometries that compare well with DFT and available experimental data. We recommend using the (10e,12o) active space since convergence to a minimum structure was more efficient than with truncated active spaces despite having similar Fe-ligand bond distances.
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Affiliation(s)
- Brian A Finney
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Sabyasachi Roy Chowdhury
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Clara Kirkvold
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
| | - Bess Vlaisavljevich
- University of South Dakota, Department of Chemistry, 414 E Clark St., Vermillion SD, 57069, USA.
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14
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Fernández-Blanco Á, Mariano LA, Piñeiro-López L, Real JA, Costa JS, Poloni R, Rodríguez-Velamazán JA. Hidden ordered structure in the archetypical Fe(pyrazine)[Pt(CN) 4] spin-crossover porous coordination compound. CrystEngComm 2022. [DOI: 10.1039/d2ce00895e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The actual low-spin state of Fe(pyrazine)Pt(CN)4 implies an ordered arrangement of the pyrazine rings, which significantly affects the spin transition.
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Affiliation(s)
- Ángel Fernández-Blanco
- Institut Laue Langevin, 71 Avenue des Martyrs, CS 20156-38042, Grenoble, France
- Univ. Grenoble Alpes, SIMaP, Grenoble-INP, CNRS, F-38042, Grenoble, France
| | - Lorenzo A. Mariano
- Univ. Grenoble Alpes, SIMaP, Grenoble-INP, CNRS, F-38042, Grenoble, France
| | - Lucía Piñeiro-López
- IMDEA Nanociencia, Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain
| | - José Antonio Real
- Departamento de Química Inorgánica, Insituto de Ciencia Molecular (ICMol), Universidad de Valencia, 46980, Paterna, Spain
| | - Jose Sanchez Costa
- IMDEA Nanociencia, Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain
| | - Roberta Poloni
- Univ. Grenoble Alpes, SIMaP, Grenoble-INP, CNRS, F-38042, Grenoble, France
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15
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Vidal D, Cirera J, Ribas-Arino J. Accurate calculation of spin-state energy gaps in Fe(III) spin-crossover systems using density functional methods. Dalton Trans 2021; 50:17635-17642. [PMID: 34806100 DOI: 10.1039/d1dt03335b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fe(III) complexes are receiving ever-increasing attention as spin crossover (SCO) systems because they are usually air stable, as opposed to Fe(II) complexes, which are prone to oxidation. Here, we present the first systematic study exclusively devoted to assess the accuracy of several exchange-correlation functionals when it comes to predicting the energy gap between the high-spin (S = 5/2) and the low-spin (S = 1/2) states of Fe(III) complexes. Using a dataset of 24 different Fe(III) hexacoordinated complexes, it is demonstrated that the B3LYP* functional is an excellent choice not only for predicting spin-state energy gaps for Fe(III) complexes undergoing spin-transitions but also for discriminating Fe(III) complexes that are either low- or high-spin in the whole range of temperatures. Our benchmark study has led to the identification of a very versatile Fe(III) compound whose SCO properties can be engineered upon changing a single axial ligand. Overall, this work demonstrates that B3LYP* is a reliable functional for screening new spin-crossover systems with tailored properties.
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Affiliation(s)
- Daniel Vidal
- Departament de Química Inorgànica i Orgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain. .,Departament de Ciència de Materials i Química Física and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Jordi Cirera
- Departament de Química Inorgànica i Orgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
| | - Jordi Ribas-Arino
- Departament de Ciència de Materials i Química Física and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
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16
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Nguyen MT, Grubel K, Zhang D, Koech PK, Malhotra D, Allec S, Rousseau R, Glezakou VA, Heldebrant DJ. Amphilic Water-Lean Carbon Capture Solvent Wetting Behavior through Decomposition by Stainless-Steel Interfaces. CHEMSUSCHEM 2021; 14:5283-5292. [PMID: 34555259 DOI: 10.1002/cssc.202101350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/01/2021] [Indexed: 06/13/2023]
Abstract
A combined experimental and theoretical study has been carried out on the wetting and reactivity of water-lean carbon capture solvents on the surface of common column packing materials. Paradoxically, these solvents are found to be equally able to wet hydrophobic and hydrophilic surfaces. The solvents are amphiphilic and can adapt to any interfacial environment, owing to their inherent heterogeneous (nonionic/ionic) molecular structure. Ab initio molecular dynamics indicates that these structures enable the formation of a strong adlayer on the surface of hydrophilic surfaces like oxidized steel which promotes solvent decomposition akin to hydrolysis from surface oxides and hydroxides. This decomposition passivates the surface, making it effectively hydrophobic, and the decomposed solvent promotes leaching of the iron into the bulk fluid. This study links the wetting behavior to the observed corrosion of the steels by decomposition of solvent at steel interfaces. The overall affect is strongly dependent on the chemical composition of the solvent in that amines are stable, whereas imines and alcohols are not. Moreover, plastic packing shows little to no solvent degradation, but an equal degree of wetting.
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Affiliation(s)
- Manh-Thuong Nguyen
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Katarzyna Grubel
- Energy Processes and Materials Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Difan Zhang
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Phillip K Koech
- Energy Processes and Materials Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Deepika Malhotra
- Energy Processes and Materials Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Sarah Allec
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Roger Rousseau
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | | | - David J Heldebrant
- Energy Processes and Materials Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
- Department of Chemical Engineering, Washington State University, Pullman, WA, USA
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17
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Mariano AL, Poloni R. Electric field-induced oxygen vacancies in YBa 2Cu 3O 7. J Chem Phys 2021; 154:224703. [PMID: 34241196 DOI: 10.1063/5.0048597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The microscopic doping mechanism behind the superconductor-to-insulator transition of a thin film of YBa2Cu3O7 was recently identified as due to the migration of O atoms from the CuO chains of the film. Here, we employ density-functional theory calculations to study the evolution of the electronic structure of a slab of YBa2Cu3O7 in the presence of oxygen vacancies under the influence of an external electric field. We find that, under massive electric fields, isolated O atoms are pulled out of the surface consisting of CuO chains. As vacancies accumulate at the surface, a configuration with vacancies located in the chains inside the slab becomes energetically preferred, thus providing a driving force for O migration toward the surface. Regardless of the defect configuration studied, the electric field is always fully screened near the surface, thus negligibly affecting diffusion barriers across the film.
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Affiliation(s)
- A Lorenzo Mariano
- University Grenoble Alpes, CNRS, Grenoble-INP, SIMaP, 38000 Grenoble, France
| | - Roberta Poloni
- University Grenoble Alpes, CNRS, Grenoble-INP, SIMaP, 38000 Grenoble, France
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