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Thamleena H, Mathew J, Sajith PK. Unraveling the Isotropic Hyperfine Coupling Constants of Nitroxide Radicals via Molecular Electrostatic Potential Analysis. J Phys Chem A 2024. [PMID: 39052117 DOI: 10.1021/acs.jpca.4c02691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Nitroxide radicals have wide and promising applications as organic magnetic materials. Modulating the isotropic hyperfine coupling constants (HFCCs) of these radicals through proper structural design is an effective strategy for their application as spin probes and spin labels. In the present work, density functional theory calculations were carried out to develop a robust descriptor based on the molecular electrostatic potential for nitrogen HFCCs of nitroxide radicals. Forty nitroxide radicals from five distinct classes, namely, derivatives of cyclic, acyclic, imino, nitronyl, and benzimidazole nitronyl nitroxides, were selected, and the molecular electrostatic potential (MESP) at the nitrogen atom (VN) of the NO moiety was calculated. The VN values efficiently capture the electronic changes associated with the steric and electronic nature of these systems. A significant correlation between VN values and the experimental HFCCs of nitrogen nuclei demonstrates the applicability of VN as a simple and efficient descriptor for monitoring HFCCs. Furthermore, a good correlation between VN and experimental nitrogen HFCCs for each class of nitroxide radicals indicates the use of VN in the evaluation of the magnetic nature of the nitroxide radicals. The findings in this work are expected to facilitate the design of novel nitroxide radicals with desirable magnetic properties based on MESP topology analysis.
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Affiliation(s)
- Hanna Thamleena
- Department of Chemistry, St. Joseph's College (Autonomous), (Affiliated to the University of Calicut), Devagiri, Kerala 673008, India
| | - Jomon Mathew
- Department of Chemistry, St. Joseph's College (Autonomous), (Affiliated to the University of Calicut), Devagiri, Kerala 673008, India
| | - Pookkottu K Sajith
- Department of Chemistry, Farook College (Autonomous), Kozhikode 673632, India
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2
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Jaworski A, Hedin N. Electron correlation and vibrational effects in predictions of paramagnetic NMR shifts. Phys Chem Chem Phys 2022; 24:15230-15244. [PMID: 35703010 DOI: 10.1039/d2cp01206e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electronic structure calculations are fundamentally important for the interpretation of nuclear magnetic resonance (NMR) spectra from paramagnetic systems that include organometallic and inorganic compounds, catalysts, or metal-binding sites in proteins. Prediction of induced paramagnetic NMR shifts requires knowledge of electron paramagnetic resonance (EPR) parameters: the electronic g tensor, zero-field splitting D tensor, and hyperfine A tensor. The isotropic part of A, called the hyperfine coupling constant (HFCC), is one of the most troublesome properties for quantum chemistry calculations. Yet, even relatively small errors in calculations of HFCC tend to propagate into large errors in the predicted NMR shifts. The poor quality of A tensors that are currently calculated using density functional theory (DFT) constitutes a bottleneck in improving the reliability of interpretation of the NMR spectra from paramagnetic systems. In this work, electron correlation effects in calculations of HFCCs with a hierarchy of ab initio methods were assessed, and the applicability of different levels of DFT approximations and the coupled cluster singles and doubles (CCSD) method was tested. These assessments were performed for the set of selected test systems comprising an organic radical, and complexes with transition metal and rare-earth ions, for which experimental data are available. Severe deficiencies of DFT were revealed but the CCSD method was able to deliver good agreement with experimental data for all systems considered, however, at substantial computational costs. We proposed a more computationally tractable alternative, where the A was computed with the coupled cluster theory exploiting locality of electron correlation. This alternative is based on the domain-based local pair natural orbital coupled cluster singles and doubles (DLPNO-CCSD) method. In this way the robustness and reliability of the coupled cluster theory were incorporated into the modern formalism for the prediction of induced paramagnetic NMR shifts, and became applicable to systems of chemical interest. This approach was verified for the bis(cyclopentadienyl)vanadium(II) complex (Cp2V; vanadocene), and the metal-binding site of the Zn2+ → Co2+ substituted superoxide dismutase (SOD) metalloprotein. Excellent agreement with experimental NMR shifts was achieved, which represented a substantial improvement over previous theoretical attempts. The effects of vibrational corrections to orbital shielding and hyperfine tensor were evaluated and discussed within the second-order vibrational perturbation theory (VPT2) framework.
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Affiliation(s)
- Aleksander Jaworski
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Niklas Hedin
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
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3
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Andersen CL, Lacerda EG, Christensen JB, Sauer SPA, Hammerich O. Prediction of the standard potentials for one-electron oxidation of N, N, N', N' tetrasubstituted p-phenylenediamines by calculation. Phys Chem Chem Phys 2021; 23:20340-20351. [PMID: 34486635 DOI: 10.1039/d1cp02315b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The formal potentials for the reversible one-electron oxidation of N,N,N',N' tetrasubstituted p-phenylenediamines in acetonitrile have been applied as a test set for benchmarking computational methods for a series of compounds with only small structural differences. The aim of the study is to propose a simple method for calculating the standard oxidation potentials, and therefore, the protocol is progressively developed by adding more terms in the energy expression. In addition, the effect of including implicit solvation models (IEFPCM, CPCM, and SMD), larger basis sets, and correlation methods are investigated. The oxidation potentials calculated using the G3MP2B3 approach with IEFPCM resulted in the best fit (R2 = 0.9624), but the slope of the correlation line, 0.74, is far from the optimal value, 1.00. B3LYP/6-311++G(d,p) and TPSSh/6-311++G(2d,p) yielded only slightly less consistent data (R2 = 0.9388 and R2 = 0.9425), but with much better slopes, 1.00 and 0.94, respectively. We conclude that it is important to investigate the basis set size and treatment of electron correlation when calculating oxidation potentials for N,N,N',N' tetrasubstituted p-phenylenediamines.
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Affiliation(s)
- Cecilie L Andersen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Evanildo G Lacerda
- Instituto de Física da Universidade de São Paulo, Rua do Matão 1371, 05508-090 São Paulo, SP, Brazil
| | - Jørn B Christensen
- Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark
| | - Stephan P A Sauer
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | - Ole Hammerich
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
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4
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Vogler S, Savasci G, Ludwig M, Ochsenfeld C. Selected-Nuclei Method for the Computation of Hyperfine Coupling Constants within Second-Order Møller-Plesset Perturbation Theory. J Chem Theory Comput 2018; 14:3014-3024. [PMID: 29762028 DOI: 10.1021/acs.jctc.8b00116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We introduce a new ansatz to compute hyperfine coupling constants of selected nuclei at the level of second-order Møller-Plesset perturbation (MP2) and double-hybrid density functional theory with reduced computational effort, opening the route to the analyis of hyperfine coupling constants of large molecular structures. Our approach is based on a reformulation of the canonical MP2 term in atomic orbitals, thus exploiting the locality of electron correlation. We show that a perturbation-including integral screening reduces the scaling behavior of the number of significant two-electron integrals to sublinear. This selected-nuclei approach allows for an efficient computation within scaled-opposite spin (SOS) RI-MP2 on massively parallelized architectures such as graphical processor units (GPUs), thus enabling studies on the influence of the environment on hyperfine coupling constants.
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Affiliation(s)
- Sigurd Vogler
- Chair of Theoretical Chemistry and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry , University of Munich (LMU) , Butenandtstrasse 7 , 81377 Munich , Germany
| | - Gökcen Savasci
- Chair of Theoretical Chemistry and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry , University of Munich (LMU) , Butenandtstrasse 7 , 81377 Munich , Germany.,Max Planck Institute for Solid State Research, Heisenbergstrasse 1 , 70569 Stuttgart , Germany
| | - Martin Ludwig
- Chair of Theoretical Chemistry and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry , University of Munich (LMU) , Butenandtstrasse 7 , 81377 Munich , Germany
| | - Christian Ochsenfeld
- Chair of Theoretical Chemistry and Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry , University of Munich (LMU) , Butenandtstrasse 7 , 81377 Munich , Germany.,Max Planck Institute for Solid State Research, Heisenbergstrasse 1 , 70569 Stuttgart , Germany
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5
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Guarracino P, Gatti T, Canever N, Abdu-Aguye M, Loi MA, Menna E, Franco L. Probing photoinduced electron-transfer in graphene-dye hybrid materials for DSSC. Phys Chem Chem Phys 2017; 19:27716-27724. [PMID: 28984327 DOI: 10.1039/c7cp04308b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We investigated the photophysical properties of a newly synthesized hybrid material composed of a triphenylamine dye covalently bound to reduced graphene oxide, potentially relevant as a stable photosensitizer in dye-sensitized solar cells. The photophysical characterization has been carried out by means of fluorescence quenching and fluorescence lifetime measurements, complemented by Electron Paramagnetic Resonance (EPR) spectroscopy, aimed at the detailed description of the photoinduced processes occurring in the hybrid and in the mixed hybrid/N-doped TiO2 material. The combined optical/magnetic study unequivocally demonstrates a fast quenching of the dye excited state in the isolated hybrid and an efficient electron transfer to N-doped titania nanopowders. In the latter case, a metastable radical cation on the dye moiety is photogenerated and the corresponding negative charge, an electron, is trapped in defect sites of the doped semiconductor oxide. The spin distribution in the stable radical has been determined by EPR spectroscopy and correlated with DFT calculations.
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Affiliation(s)
- Paola Guarracino
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, 35131 Padova, Italy.
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6
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Hermosilla L, Calle P, García de la Vega JM. Modeling EPR parameters of nitrogen containing conjugated radical cations. RSC Adv 2015. [DOI: 10.1039/c5ra08758a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DFT investigation on conjugated radical cations containing14N nucleus to obtain accurate isotropic hyperfine coupling constants.
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Affiliation(s)
- L. Hermosilla
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - P. Calle
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | - J. M. García de la Vega
- Departamento de Química Física Aplicada
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
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7
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Verma P, Perera A, Morales JA. Massively parallel implementations of coupled-cluster methods for electron spin resonance spectra. I. Isotropic hyperfine coupling tensors in large radicals. J Chem Phys 2013; 139:174103. [DOI: 10.1063/1.4827298] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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8
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Tanaka A, Nakashima K. DFT studies of ESR parameters for N-O centered radicals, N-alkoxyaminyl and aminoxyl radicals. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2011; 49:603-610. [PMID: 21823164 DOI: 10.1002/mrc.2792] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 05/22/2011] [Accepted: 06/17/2011] [Indexed: 05/31/2023]
Abstract
Theoretical calculations of ESR parameters for aminoxyl radicals have been widely studied using the density functional theory (DFT) calculations. However, the isomer N-alkoxyaminyl radicals have been limitedly studied. With the use of experimental data for 46 N-alkoxyaminyl and 38 aminoxyl radicals, the isotropic (14)N hyperfine coupling constants (aN ) and g-factors have been theoretically estimated by several DFT calculations. The best calculation scheme of aN for N-alkoxyaminyl radicals was PCM/B3LYP/6-31 + + G(d,p) (R(2) = 0.9519, MAE = 0.034 mT), and that for aminoxyl radicals was PCM/BHandHLYP/6-31 + + G(3df,3pd) (R(2) = 0.9336, MAE = 0.057 mT). For aminoxyl radicals, the solvation models in calculations enhanced the accuracy of reproducibility. In contrast, for N-alkoxyaminyl radicals the calculations with solvation models provided no improvement. The differences in the best functionals between two types of radicals were thought to come from the contribution ratios of neutral and dipolar canonical structures in resonance forms. The aN for N-alkoxyaminyl radicals that were stabilized by small contribution of dipolar canonical structures could be precisely reproduced by B3LYP with only 20% HF exact exchange. In contrast, the aN for aminoxyl radicals stabilized by large contribution of dipolar canonical structures was well reproduced by BHandHLYP with 50% HF exchange. The best calculation scheme of g-factors was IEFPCM/B3LYP/6-31 + G(d,p) (R(2) = 0.9767, MAE = 0.0001) for not only aminoxyl but also N-alkoxyaminyl radicals.
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Affiliation(s)
- Akio Tanaka
- Organic Synthesis Research Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka 554-8558, Japan.
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10
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Kossmann S, Kirchner B, Neese F. Performance of modern density functional theory for the prediction of hyperfine structure: meta-GGA and double hybrid functionals. Mol Phys 2010. [DOI: 10.1080/00268970701604655] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Hammerich O, Hansen T, Thorvildsen A, Christensen JB. Electrochemical One-Electron Oxidation of Low-Generation Polyamidoamine-Type Dendrimers with a 1,4-Phenylenediamine Core. Chemphyschem 2009; 10:1805-24. [DOI: 10.1002/cphc.200900233] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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12
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Zarycz N, Botek E, Champagne B, Sciannaméa V, Jérôme C, Detrembleur C. Joint Theoretical Experimental Investigation of the Electron Spin Resonance Spectra of Nitroxyl Radicals: Application to Intermediates in in Situ Nitroxide Mediated Polymerization (in Situ NMP) of Vinyl Monomers. J Phys Chem B 2008; 112:10432-42. [DOI: 10.1021/jp803552x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Natalia Zarycz
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
| | - Edith Botek
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
| | - Benoît Champagne
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
| | - Valérie Sciannaméa
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
| | - Christine Jérôme
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
| | - Christophe Detrembleur
- Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, Departamento de Física, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina, and Center for Education and Research on Macromolecules (CERM), University of Liège, Sart-Tilman, B6, B-4000 Liège, Belgium
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Alberti A, Galasso V, Kovac B, Modelli A, Pichierri F. Probing the molecular and electronic structure of capsaicin: a spectroscopic and quantum mechanical study. J Phys Chem A 2008; 112:5700-11. [PMID: 18507451 DOI: 10.1021/jp801890g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The conformational preferences of capsaicin were investigated by using the hybrid meta density functional theory (DFT) method MPWB1K. Its flexible, pendant side chain allows for a multitude of conformations only slightly different in energy. The distinctive vibrational features of the most stable conformers were characterized. To elucidate the most favorable reaction sites of capsaicin for radical scavenging, various homolytic bond-dissociation energies were also calculated. Of the possible radical intermediates, the allyl and benzyl radicals are energetically preferred. The filled and empty electronic structures of capsaicin were investigated by exploiting the photoelectron and electron-transmission spectra also of reference molecules and suitable quantum-mechanical calculations. On this basis, a reliable pattern of the vertical ionization energies and electron-attachment energies of capsaicin was proposed. The frontier pi molecular orbitals are concentrated over the vanillyl moiety, with a modest influence of the amidic-aliphatic chain. The (negative) first vertical electron affinity is predicted to be similar to that of benzene. The absorption spectrum of capsaicin and its change by conversion into a phenolic deprotonated anion (modest bathochromic displacement) or a phenoxyl neutral radical (from colorless to red) were interpreted with time-dependent DFT calculations. ESR measurements following chemical or electrochemical reduction of capsaicin did not lead to detection of the corresponding radical anion. The spectra show fragmentation of the original molecule and formation of a variety of radical species which are believed to have a semiquinonic structure.
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Affiliation(s)
- A Alberti
- ISOF, Area della Ricerca del CNR, Via Gobetti 101, I-40129 Bologna, Italy
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14
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Norberg D, Larsson PE, Salhi-Benachenhou N. Rearrangement and Hydrogen Scrambling Pathways of the Toluene Radical Cation: A Computational Study. J Phys Chem A 2008; 112:4694-702. [DOI: 10.1021/jp711166d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Daniel Norberg
- Department of Quantum Chemistry, Uppsala University, Box 518, 751 20 Uppsala, Sweden, and SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Per-Erik Larsson
- Department of Quantum Chemistry, Uppsala University, Box 518, 751 20 Uppsala, Sweden, and SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
| | - Nessima Salhi-Benachenhou
- Department of Quantum Chemistry, Uppsala University, Box 518, 751 20 Uppsala, Sweden, and SINTEF Materials and Chemistry, N-7465 Trondheim, Norway
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