Journal ArticleDOI
Valence bond description of antiferromagnetic coupling in transition metal dimers
TLDR
In this paper, a single configuration model containing nonorthogonal magnetic orbitals is developed to represent the important features of the antiferromagnetic state of a transition metal dimer.Abstract:
A single configuration model containing nonorthogonal magnetic orbitals is developed to represent the important features of the antiferromagnetic state of a transition metal dimer. A state of mixed spin symmetry and lowered space symmetry is constructed which has both conceptual and practical computational value. Either unrestricted Hartree–Fock theory or spin polarized density functional theory, e.g., Xα theory, can be used to generate the mixed spin state wave function. The most important consequence of the theory is that the Heisenberg exchange coupling constant J can be calculated simply from the energies of the mixed spin state and the highest pure spin multiplet.read more
Citations
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Journal ArticleDOI
Valence electronic structure of sublimated Fe4 single-molecule magnets: an experimental and theoretical characterization
Silviya Ninova,Valeria Lanzilotto,Luigi Malavolti,Luca Rigamonti,Brunetto Cortigiani,Matteo Mannini,Federico Totti,Roberta Sessoli +7 more
TL;DR: In this article, the valence electronic structures of two single-molecule magnets (SMMs), [Fe4(L)2(dpm)6] and [Fe 4(L 2(pta)6], are investigated by means of ultraviolet photoemission spectroscopy (UPS) and ab initio calculations.
Journal ArticleDOI
Theoretical investigation on triagonal symmetry copper trimers: magneto-structural correlation and spin frustration.
TL;DR: According to the analysis of the molecular orbitals and the variation of the spin-state energies versus the ratio of the magnetic coupling constants, it is found that there exists spin frustration phenomenon in these complexes.
Journal ArticleDOI
Bond Length Effect on Odd-Electron Behavior in Single-Walled Carbon Nanotubes
TL;DR: In this article, a view of the single-walled nanotube reactivity based on unpairing odd electrons is suggested, and it is shown that in the framework of the UHF single-determinant approach, the electron unpaireding critically depends on the corresponding interatomic C−C distance, and as a result of the dependence, a perfect (4,4) nanotubes should be attributed to species with intermediate radical behavior.
Journal ArticleDOI
Quantum-chemical study of spin crossover in cobalt complexes with an o-benzoquinone ligand
Andrey G. Starikov,Andrey G. Starikov,Alyona A. Starikova,Vladimir I. Minkin,Vladimir I. Minkin +4 more
TL;DR: In this article, a density functional theory method was used to model cationic cobalt complexes based on o-benzoquinone and a di-tert-butyl derivative of 2,11-diaza[3.3]-pyridinophane.
Journal ArticleDOI
A DFT based ligand field model for magnetic exchange coupling in transition metal dimmer complexes: (i) principles
TL;DR: In this paper, a ligand field model for magnetic exchange coupling in homonuclear transition metal dimmer complexes is presented, based on a model of localized d-electrons and on a procedure allowing to express its parameters in terms of exchange and Coulomb integrals from DFT calculations.
References
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Journal ArticleDOI
New Approach to the Theory of Superexchange Interactions
TL;DR: In this article, the theory of indirect exchange in poor conductors is examined from a new viewpoint in which the $d$ (or $f$) shell electrons are placed in wave functions assumed to be exact solutions of the problem of a single $d-electron in the presence of the full diamagnetic lattice.
Journal ArticleDOI
Orbital interactions in metal dimer complexes
TL;DR: In this paper, the effect of geometrical distortions, electronegativity, and variation of substituents on the magnetic interaction in dimeric systems is examined in detail for singly bridged L,M-X-ML, (n = 3, 4, 5); Cu~C16~ and other doubly bridging species where the bridging ligands are halogens, OR, pyridine N-oxides, oxalate, squarate; and the acetate bridged dimers C u ~ (R C 0 0 ) 4.
Journal ArticleDOI
Quantum Theory of Many-Particle Systems. III. Extension of the Hartree-Fock Scheme to Include Degenerate Systems and Correlation Effects
TL;DR: In this paper, it was shown that if the total wave function is approximated by a projection of a single determinant, the description of the system may be reduced to the ordinary Hartree-Fock scheme treating this determinant.
Book ChapterDOI
Scattered-Wave Theory of the Chemical Bond
TL;DR: In the self-consistent field (SCF)-Xα scattered-wave model that is also a first-principle technique, there is no basis set problem because Schrodinger's equation for an Xα potential is numerically integrated as discussed by the authors.