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Palii A, Korchagin D, Kondrina K, Aldoshin S, Zilberg S, Tsukerblat B. Spin polarization effects in trigonal mixed-valence complexes exhibiting double exchange supported by external spin-cores. J Chem Phys 2023; 158:2890771. [PMID: 37191212 DOI: 10.1063/5.0147019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 04/27/2023] [Indexed: 05/17/2023] Open
Abstract
The theory of the magnetic coupling between the localized spins, mediated by the mobile excess electron, is generalized to the case of a trigonal, six-center, four-electron molecule with partial valence delocalization. The combination of the electron transfer occurring within the valence-delocalized subsystem and the interatomic exchange producing coupling of the spin of the mobile electron of valence-delocalized fragment with the three localized spins forming the valence-localized subsystem leads to the appearance of a special kind of double exchange (DE), termed the "external core double exchange" (ECDE), in order to distinguish such DE from the conventional "internal core double exchange" for which the mobile electron is coupled with the spin-cores on the same center via the intra-atomic exchange. The effect of the ECDE on the ground spin state of the considered trigonal molecule is compared with earlier reported effect produced by DE in the four-electron, mixed-valence (MV) trimer. A high diversity of the ground spin states is revealed, depending on the relative magnitudes and signs of the electron transfer and interatomic exchange parameters, with part of these states not appearing to be the ground states in a trigonal trimer exhibiting DE. We briefly discuss some examples of trigonal MV systems from the point of view of the possibility to have different combinations of signs of the transfer and exchange parameters and, accordingly, different ground spin states. The tentative role of the considered systems in molecular electronics and spintronics is also noticed.
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Affiliation(s)
- Andrew Palii
- Federal Research Center of Problems of Chemical Physics and Medicine Chemistry, Chernogolovka, Moscow Region 142432, Russian Federation
| | - Denis Korchagin
- Federal Research Center of Problems of Chemical Physics and Medicine Chemistry, Chernogolovka, Moscow Region 142432, Russian Federation
| | - Ksenya Kondrina
- Federal Research Center of Problems of Chemical Physics and Medicine Chemistry, Chernogolovka, Moscow Region 142432, Russian Federation
- Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudny, Moscow Region 141701, Russian Federation
| | - Sergey Aldoshin
- Federal Research Center of Problems of Chemical Physics and Medicine Chemistry, Chernogolovka, Moscow Region 142432, Russian Federation
| | - Shmuel Zilberg
- Department of Chemical Sciences, Ariel University, 40700 Ariel, Israel
| | - Boris Tsukerblat
- Department of Chemical Sciences, Ariel University, 40700 Ariel, Israel
- Department of Chemistry, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
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Houck SE, Mayhall NJ. A Combined Spin-Flip and IP/EA Approach for Handling Spin and Spatial Degeneracies: Application to Double Exchange Systems. J Chem Theory Comput 2019; 15:2278-2290. [DOI: 10.1021/acs.jctc.8b01268] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shannon E. Houck
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Nicholas J. Mayhall
- Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24060, United States
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Gupta T, Rajaraman G. Modelling spin Hamiltonian parameters of molecular nanomagnets. Chem Commun (Camb) 2018; 52:8972-9008. [PMID: 27366794 DOI: 10.1039/c6cc01251e] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular nanomagnets encompass a wide range of coordination complexes possessing several potential applications. A formidable challenge in realizing these potential applications lies in controlling the magnetic properties of these clusters. Microscopic spin Hamiltonian (SH) parameters describe the magnetic properties of these clusters, and viable ways to control these SH parameters are highly desirable. Computational tools play a proactive role in this area, where SH parameters such as isotropic exchange interaction (J), anisotropic exchange interaction (Jx, Jy, Jz), double exchange interaction (B), zero-field splitting parameters (D, E) and g-tensors can be computed reliably using X-ray structures. In this feature article, we have attempted to provide a holistic view of the modelling of these SH parameters of molecular magnets. The determination of J includes various class of molecules, from di- and polynuclear Mn complexes to the {3d-Gd}, {Gd-Gd} and {Gd-2p} class of complexes. The estimation of anisotropic exchange coupling includes the exchange between an isotropic metal ion and an orbitally degenerate 3d/4d/5d metal ion. The double-exchange section contains some illustrative examples of mixed valance systems, and the section on the estimation of zfs parameters covers some mononuclear transition metal complexes possessing very large axial zfs parameters. The section on the computation of g-anisotropy exclusively covers studies on mononuclear Dy(III) and Er(III) single-ion magnets. The examples depicted in this article clearly illustrate that computational tools not only aid in interpreting and rationalizing the observed magnetic properties but possess the potential to predict new generation MNMs.
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Affiliation(s)
- Tulika Gupta
- Department of Chemistry, IIT Powai, Mumbai-400076, India.
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Pradines B, Lacombe L, Guihéry N, Suaud N. Study of the Electronic Structure of NiGa
2
S
4
and Extraction of the Spin Hamiltonian Parameters from Ab Initio Calculations. Eur J Inorg Chem 2017. [DOI: 10.1002/ejic.201700974] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Barthélémy Pradines
- Laboratoire de Chimie et Physique Quantiques, UMR5626 Université de Toulouse 3, Paul Sabatier 118 route de Narbonne 31062 Toulouse France
| | - Lionel Lacombe
- Laboratoire de Chimie et Physique Quantiques, UMR5626 Université de Toulouse 3, Paul Sabatier 118 route de Narbonne 31062 Toulouse France
| | - Nathalie Guihéry
- Laboratoire de Chimie et Physique Quantiques, UMR5626 Université de Toulouse 3, Paul Sabatier 118 route de Narbonne 31062 Toulouse France
| | - Nicolas Suaud
- Laboratoire de Chimie et Physique Quantiques, UMR5626 Université de Toulouse 3, Paul Sabatier 118 route de Narbonne 31062 Toulouse France
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Trinquier G, Chilkuri VG, Malrieu JP. When a single hole aligns several spins: double exchange in organic systems. J Chem Phys 2014; 140:204113. [PMID: 24880272 DOI: 10.1063/1.4878498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The double exchange is a well-known and technically important phenomenon in solid state physics. Ionizing a system composed of two antiferromagnetically coupled high-spin units, the ground state of which is a singlet state, may actually produce a high-spin ground state. This work illustrates the possible occurrence of such a phenomenon in organic chemistry. The here-considered high-spin units are triangulenes, the ground state of which is a triplet. Bridging two of them through a benzene ring produces a molecular architecture of singlet ground state. A careful exploitation of a series of unrestricted density functional calculations enables one to avoid spin contamination in the treatment of the doublet states and shows that under ionization the system becomes of quartet multiplicity in its ground state. The possibility to align more than three spins from conjugated hydrocarbon polyradicals is explored, considering partially hydrogenated triangulenes. A dramatic example shows that ionization of a singlet ground state molecule may generate a decuplet.
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Affiliation(s)
- Georges Trinquier
- Laboratoire de Chimie et Physique Quantiques, CNRS, UMR 5626, IRSAMC, Université Paul-Sabatier, 118 Rte de Narbonne, 31062 Toulouse Cedex, France
| | - Vijay Gopal Chilkuri
- Laboratoire de Chimie et Physique Quantiques, CNRS, UMR 5626, IRSAMC, Université Paul-Sabatier, 118 Rte de Narbonne, 31062 Toulouse Cedex, France
| | - Jean-Paul Malrieu
- Laboratoire de Chimie et Physique Quantiques, CNRS, UMR 5626, IRSAMC, Université Paul-Sabatier, 118 Rte de Narbonne, 31062 Toulouse Cedex, France
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7
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Gopal Chilkuri V, Trinquier G, Ben Amor N, Malrieu JP, Guihéry N. In Search of Organic Compounds Presenting a Double Exchange Phenomenon. J Chem Theory Comput 2013; 9:4805-15. [PMID: 26583399 DOI: 10.1021/ct4005855] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The objective of this paper is to design a consistent series of organic molecules that may present a double exchange mechanism and study their low energy spectrum using spin unrestricted Density Functional Theory. For this purpose, organic tetra-methylene methane units having an S = 1 spin ground state and diamagnetic organic bridges are taken as building blocks for constructing molecules having two or more magnetic units. When biunit systems are ionized, the ground state of the resulting molecular ions may be either a quartet, if the spectrum is ruled by a double exchange mechanism, or a doublet, if it obeys the logic of a monoelectronic picture. A strategy based on the physical analysis of the leading interactions is followed in order to energetically favor a high-spin ground state. It is shown that the most promising compounds involve bridges that have both a large gap between the highest occupied and the lowest unoccupied molecular orbitals and small coefficients on the atoms to which the magnetic units are connected. While the followed strategy enables one to conceive organic compounds exhibiting a double exchange phenomenon, it is shown that the electronic mechanism ruling the spectrum of such organic double exchange compounds is different from that of their inorganic homologues. A new method to reconstruct the spectrum of low energy from various spin unrestricted DFT solutions is proposed and applied. Finally monodimensional and bidimensional periodic lattices based on the most promising organic architecture are suggested.
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Affiliation(s)
- Vijay Gopal Chilkuri
- Laboratoire de Chimie et de Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse 3 , 118 route de Narbonne, F-31062 Toulouse Cédex 4, France
| | - Georges Trinquier
- Laboratoire de Chimie et de Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse 3 , 118 route de Narbonne, F-31062 Toulouse Cédex 4, France
| | - Nadia Ben Amor
- Laboratoire de Chimie et de Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse 3 , 118 route de Narbonne, F-31062 Toulouse Cédex 4, France
| | - Jean-Paul Malrieu
- Laboratoire de Chimie et de Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse 3 , 118 route de Narbonne, F-31062 Toulouse Cédex 4, France
| | - Nathalie Guihéry
- Laboratoire de Chimie et de Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse 3 , 118 route de Narbonne, F-31062 Toulouse Cédex 4, France
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Malrieu JP, Caballol R, Calzado CJ, de Graaf C, Guihéry N. Magnetic interactions in molecules and highly correlated materials: physical content, analytical derivation, and rigorous extraction of magnetic Hamiltonians. Chem Rev 2013; 114:429-92. [PMID: 24102410 DOI: 10.1021/cr300500z] [Citation(s) in RCA: 282] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Jean Paul Malrieu
- Laboratoire de Chimie et Physique Quantiques, Université de Toulouse 3 , 118 route de Narbonne, 31062 Toulouse, France
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Chibotaru LF. Ab InitioMethodology for Pseudospin Hamiltonians of Anisotropic Magnetic Complexes. ADVANCES IN CHEMICAL PHYSICS 2013. [DOI: 10.1002/9781118571767.ch6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Coulaud E, Guihéry N, Malrieu JP, Hagebaum-Reignier D, Siri D, Ferré N. Analysis of the physical contributions to magnetic couplings in broken symmetry density functional theory approach. J Chem Phys 2012; 137:114106. [DOI: 10.1063/1.4752412] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Malrieu JP. Single reference Coupled Cluster treatment of nearly degenerate problems: Cohesive energy of antiferromagnetic lattices of spin 1 centers. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2011.11.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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12
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Soncini A, Mallah T, Chibotaru LF. Molecular Spintronics in Mixed-Valence Magnetic Dimers: The Double-Exchange Blockade Mechanism. J Am Chem Soc 2010; 132:8106-14. [DOI: 10.1021/ja101887f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alessandro Soncini
- Institute for Nanoscale Physics and Chemistry (INPAC) and Division of Quantum and Physical Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris Sud 11, Rue George Clemenceau, 91405 Orsay, France
| | - Talal Mallah
- Institute for Nanoscale Physics and Chemistry (INPAC) and Division of Quantum and Physical Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris Sud 11, Rue George Clemenceau, 91405 Orsay, France
| | - Liviu F. Chibotaru
- Institute for Nanoscale Physics and Chemistry (INPAC) and Division of Quantum and Physical Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium, and Institut de Chimie Moléculaire et des Matériaux d’Orsay, Université Paris Sud 11, Rue George Clemenceau, 91405 Orsay, France
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Maurice R, Bastardis R, Graaf CD, Suaud N, Mallah T, Guihéry N. Universal Theoretical Approach to Extract Anisotropic Spin Hamiltonians. J Chem Theory Comput 2009; 5:2977-84. [PMID: 26609979 DOI: 10.1021/ct900326e] [Citation(s) in RCA: 226] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Monometallic Ni(II) and Co(II) complexes with large magnetic anisotropy are studied using correlated wave function based ab initio calculations. Based on the effective Hamiltonian theory, we propose a scheme to extract both the parameters of the zero-field splitting (ZFS) tensor and the magnetic anisotropy axes. Contrarily to the usual theoretical procedure of extraction, the method presented here determines the sign and the magnitude of the ZFS parameters in any circumstances. While the energy levels provide enough information to extract the ZFS parameters in Ni(II) complexes, additional information contained in the wave functions must be used to extract the ZFS parameters of Co(II) complexes. The effective Hamiltonian procedure also enables us to confirm the validity of the standard model Hamiltonian to produce the magnetic anisotropy of monometallic complexes. The calculated ZFS parameters are in good agreement with high-field, high-frequency electron paramagnetic resonance spectroscopy and frequency domain magnetic resonance spectroscopy data. A methodological analysis of the results shows that the ligand-to-metal charge transfer configurations must be introduced in the reference space to obtain quantitative agreement with the experimental estimates of the ZFS parameters.
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Affiliation(s)
- Rémi Maurice
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - Roland Bastardis
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - Coen de Graaf
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - Nicolas Suaud
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - Talal Mallah
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
| | - Nathalie Guihéry
- Laboratoire de Chimie et Physique Quantiques, IRSAMC/UMR5626, Université de Toulouse III, 118 route de Narbonne, F-31062 Toulouse Cédex 4, France, Laboratoire de Mathématiques, Physiques et Systemes, Université de Perpignan Via Domitia, 52 Avenue Paul Alduy, 66860 Perpignan, France, Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Marcel lí Domingo s/n, 43007 Tarragona, Spain, Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris sud 11, 91405 Orsay, France, and Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010, Barcelona, Spain
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Angeli C, Sparta† M, Cimiraglia R. A priori complete active space self consistent field localized orbitals: an application on linear polyenes. Mol Phys 2007. [DOI: 10.1080/00268970500417903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Celestino Angeli
- a Dipartimento di Chimica , Università di Ferrara , Via Borsari 46, I-44100 Ferrara, Italy
| | - Manuel Sparta†
- a Dipartimento di Chimica , Università di Ferrara , Via Borsari 46, I-44100 Ferrara, Italy
| | - Renzo Cimiraglia
- a Dipartimento di Chimica , Università di Ferrara , Via Borsari 46, I-44100 Ferrara, Italy
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Bastardis R, Guihéry N, Suaud N, de Graaf C. Competition between double exchange and purely magnetic Heisenberg models in mixed valence systems: Application to half-doped manganites. J Chem Phys 2006; 125:194708. [PMID: 17129151 DOI: 10.1063/1.2375119] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A truncated Hubbard model is developed for the description of the electronic structure of odd-electron TM-L-TM units (TM=transition metal and L=ligand). The model variationally treats both the double exchange and purely magnetic Heisenberg configurations. This Hubbard model can either be mapped on a purely magnetic Heisenber model in which the bridging oxygen is also magnetic or on a double exchange model owing to the hybridization of the magnetic and ligand or bitals. The purely magnetic Heisenberg model is analytically solved in the general case of two metals (having n magnetic orbitals) bridged by a magnetic oxygen. The comparison of the analytical expressions of the Heisenberg energies to those of the double exchange model reveals that the two model spectra are identical except for one state which does not belong to the model space of the double exchange Hamiltonian. Consequently, the fitting of the model spectra to accurate ab initio spectra does not discriminate between the physically different models. These concepts are illustrated for the Mn-O-Mn unit (or Zener polaron) found in the half-doped manganite Pr(0.6)Ca(0.4)MnO3. It is shown that in the present case the projections of the ab initio ground state wave function onto both model spaces are almost identical provided that one uses properly localized orbitals, proving that the magnetic description of the Zener polaron and the double exchange viewpoint of the electronic structure are equally valid.
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Affiliation(s)
- Roland Bastardis
- Laboratoire de Physique Quantique, IRSAMC/UMR5626, Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse Cedex 4, France.
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Ayed T, Guihéry N, Tangour B, Barthelat JC. Theoretical Study of the Metal–Metal Interaction in Dipalladium(I) Complexes. Theor Chem Acc 2006. [DOI: 10.1007/s00214-006-0086-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Accurate Determination of the Electronic Structure Parameters of the Spin Ladder Compounds SrCu2O3, Sr2Cu3O5 and CaCu2O3. Theor Chem Acc 2006. [DOI: 10.1007/s00214-006-0099-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Bordas E, Caballol R, Graaf CD, Malrieu JP. Toward a variational treatment of the magnetic coupling between centers with elevated spin moments. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2004.09.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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22
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Augustyniak-Jablokow MA, Borshch SA, Daniel C, Hartl H, Yablokov YV. EPR study of the magnetic states of a mixed-valence VIV4VV2 alkoxypolyoxovanadium cluster. NEW J CHEM 2005. [DOI: 10.1039/b412427h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Carissan Y, Heully JL, Guihéry N, Alary F. A study of the correlation effects upon the modelization of the double exchange phenomenon. J Chem Phys 2004; 121:9453-60. [PMID: 15538866 DOI: 10.1063/1.1806415] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A previous work by the authors has shown that the usual spin Hamiltonian used to model the magnetic spectra of mixed valence compounds was not sufficient to reproduce the magnetic spectrum of the molecule [Fe(2)(OH)(3)(NH(3))(6)](2+). In the present paper, the spin Hamiltonian is confronted to correlated ab initio calculations. The discrepancy between this Hamiltonian and the calculations is investigated and explained. It is pointed out that the multiconfigurational nature of the transition metal is responsible for this discrepancy. However, we show that this effect can easily be treated at the complete active space self-consistent field (CASSCF) level and that no further correlation treatment is needed. The spin Hamiltonian, which reproduces very well the minimal CASSCF results, could not be improved to recover the multireference effects.
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Affiliation(s)
- Yannick Carissan
- Laboratoire de Physique Quantique, IRSAMC/UMR5626, Université Paul Sabatier, 118 Route de Narbonne, F-31062 Toulouse Cedex 4, France.
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Taratiel D, Guihéry N. A refined model of the double exchange phenomenon: Test on the stretched N2+ molecule. J Chem Phys 2004; 121:7127-35. [PMID: 15473778 DOI: 10.1063/1.1786913] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The N2+ molecule is studied at different interatomic distances as a model molecule for the double exchange mechanism. The energy spectrum as well as the wave functions of the lowest states are analyzed and confronted both with the usual model of double exchange and with a recently proposed refined model. It is shown that the usual model fails to reproduce the energy spacings while the refined model is valid on a large domain of interatomic distances (in the magnetic regime). The study of a model molecule on a large domain of interatomic distances makes it possible to systematically investigate several regimes associated with different energetic state orderings. The perfect agreement between the refined model and the computed energies in the whole domain of stretched distances shows its applicability to a large number of real compounds. Finally, the respective contributions of dynamical and nondynamical correlations are analyzed.
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Affiliation(s)
- David Taratiel
- Laboratoire de Physique Quantique, IRSAMC/UMR5626, Université Paul Sabatier, 118 route de Narbonne, F-31062 Toulouse, Cedex 4, France
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