Direct theoretical <i>ab initio</i> calculations in exchange coupled copper(II) dimers: Influence of the choice of the atomic basis set on the singlet–triplet splitting in modeled and real copper dimers

Loth, Philippe De; Daudey, J. P.; Astheimer, Harald; Walz, L.; Haase, Wolfgang

doi:10.1063/1.448626

Cited by 41 publications

(25 citation statements)

References 10 publications

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“…The influence of modelling has been indicated already by some calculations on dimers. 13 Calculations of the spin energy splitting in dimeric complexes as proposed by Hay et aL2l and de Loth et start with the definition of the spin states using the SOMOs obtained from an SCF calculation. Already on this level a careful analysis of the AOs that construct the SOMOs can explain magnetic properties of exchange-coupled compounds, e.g.…”

Section: Discussionmentioning

confidence: 99%

Exchange interaction in linear trimeric copper(II) complexes with ferromagnetic and antiferromagnetic ground states

Gehring¹,

Astheimer²,

Haase³

1987

J. Chem. Soc., Faraday Trans. 2

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The different magnetic properties of two linear trimeric copper(I1) complexes, a complex with a ferromagnetic spin ground state, [ C U ~( C ~H ~C ~~) ~{ ( C ~H ~) ~N C ~H ~O } ~( C H ~O H ) ~] ~1, and a complex with an antiferromagnetic ground state, [ C U ~{ ( C ~H ~) ~N C ~H , N ( H)C3H60}2( OH)2]A (C104)2, 2, are described using MO methods and are discussed. 1 presents a folded geometry, whereas in 2 the coordination planes around the copper atoms are nearly coplanar. SCF calculations have been performed on models of both compounds. The coefficients of the AOs of the metal centres and ligands involved in the three singly occupied MOs are reported and their different contributions are discussed. The orthogonality of the magnetic orbitals in 1 is due to the non-coplanarity of the Cul and Cu2 coordination planes, which leads to the predominant ferromagnetic exchange interaction. In 2 the nature of the magnetic orbitals favours an antiferromagnetic interaction as consequence of the nearly planar geometry.

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Section: Discussionmentioning

confidence: 99%

Exchange interaction in linear trimeric copper(II) complexes with ferromagnetic and antiferromagnetic ground states

Gehring¹,

Astheimer²,

Haase³

1987

J. Chem. Soc., Faraday Trans. 2

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“…For the l -system only singly excited states over its singlet (closed shell) ground state are previewed. [7,8,9] These states apparently classify according to their total spin which can be thus singlet and triplet. For that reason the resolvent eq.…”

Section: C3 Resolvents For the L -System Polarizationmentioning

confidence: 99%

“…The ab initio methods are potentially capable to solve the problem (see below). [7,8,9,10,11] However, the systems of real interest in this area may contain thousands of atoms of which hundreds are going to be transition metal ones. [3,4,5,6] Within the ab initio realm such systems require the account of correlations (both dynamical and noindynamical) at a level which causes the scaling of the requred computational resources as N 7 where N is the number of orbitals involved.…”

Section: Introductionmentioning

confidence: 99%

“…The dependence of the result on the basis state used has been established as well. [9] The DFT based methods recently received considerable attention in this context. [12,13] The success reported for the DFT-based techniques [12,13] heavily relies upon the possibility to obtain the broken symmetry solutions in the UHF setting for the respective molecules.…”

Section: Introductionmentioning

confidence: 99%

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Effective Hamiltonian Crystal Field for Magnetic Interactions in Polynuclear Transition Metal Complexes. Sequential Derivation and Exemplary Numerical Estimates

Tchougréeff¹

2013

Preprint

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By this we extend our work of the year 1992 devoted to calculating the intrashell excitations in the d-shells of coordination compounds of the first transition metal row, which resulted in the Effective Hamiltonian Crystal Field (EHCF) method, to their polynuclear analogs in order to assure the description of several open d-shells and of magnetic interactions of the effective spins residing in these shells. This is a challenging task since it requires improving the precision of ca. 1000 cm −1 (that of describing the excitation energies of the single dshells by the already well successful EHCF method) to the that of ca. 10 ÷ 100 cm −1 characteristic for the energies required to reorient the spins i.e. eventually by two orders of magnitude. This is performed within the same paradigm as used for the EHCF method: the concerted usage of the McWeeny's group-function approximation and the Löwdin partition technique. These are applied to develop the effective description of the d-system of the polynuclear complexes, composed of several d-shells, including the working formulae for the exchange parameters between the d-shells belonging to different transition metal ions. These formulae are implemented in the package MagAîxTic and tested against a series of binuclear complexes of trivalent Cr and Fe cations featuring µ-oxygen superexchange paths in order to confirm the reproducibility of the trends in the series of values of exchange parameters for the compounds differing by the chemical substitutions and other details of composition and structure. The results of calculations are in a reasonable agreement with available experimental data and other theoretical methods.

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“…As shown in ref. (18) the electronic description of the bridging atoms can be made only with the use of a sufficient atomic basis set. On account of that, a split-valence basis obtained by a contraction (3/ 1) of four Gaussian functions was used for the oxygen atoms.…”

Section: Computational Detailsmentioning

confidence: 99%

Ab initio SCF + CI direct calculation of the exchange interaction in aromatic N-oxide bridged copper(II) dimers. Comparison of the structural parameters' effects on modelled and real geometries

Nepveu¹,

Haase²,

Astheimer³

1986

J. Chem. Soc., Faraday Trans. 2

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The singlet-triplet (S-T) splitting energy of aromatic N-oxide bridged copper(I1) dimers has been calculated using an ab initio SCF+CI treatment. Modelled molecules have been used to point out the chemical and geometrical factors which are suspected to influence the metal-metal interaction in this series of compounds. The direct substituent effects are very weak, but they govern the geometry of the complexes owing to the intramolecular interactions. The bridging angle and copper-copper distance have an important, but not decisive influence on the exchange coupling. The variation of the copper-oxygen bond length has a drastic effect on the 2J constant. Its shortening in the models leads to very strong antiferromagnetic couplings comparable to the experimental ones. The deviation of the halogen atoms out of the Cu,Oz plane leads to a very strong decrease of the antiferromagnetic interaction. Both effects reproduce a shift of 2J comparable to the experimental range (12000 cm-'l). Using real geometries the calculated S-T energy gaps are in agreement with the experimental ones and with the calculations on modelled molecules.

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Direct theoretical ab initio calculations in exchange coupled copper(II) dimers: Influence of the choice of the atomic basis set on the singlet–triplet splitting in modeled and real copper dimers

Cited by 41 publications

References 10 publications

Exchange interaction in linear trimeric copper(II) complexes with ferromagnetic and antiferromagnetic ground states

Exchange interaction in linear trimeric copper(II) complexes with ferromagnetic and antiferromagnetic ground states

Effective Hamiltonian Crystal Field for Magnetic Interactions in Polynuclear Transition Metal Complexes. Sequential Derivation and Exemplary Numerical Estimates

Ab initio SCF + CI direct calculation of the exchange interaction in aromatic N-oxide bridged copper(II) dimers. Comparison of the structural parameters' effects on modelled and real geometries

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