Journal ArticleDOI
Valence bond description of antiferromagnetic coupling in transition metal dimers
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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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Synthesis, structure, magnetic behavior, and theoretical analysis of diazine-bridged magnetic ladders: Cu(quinoxoline)X2 and Cu(2,3-dimethylpyrazine)X2 (X = Cl, Br).
Joaquim Jornet-Somoza,Núria Codina-Castillo,Mercè Deumal,Fernando Mota,Juan J. Novoa,Robert T. Butcher,Mark M. Turnbull,Brian Keith,Christopher P. Landee,Jan L. Wikaira +9 more
TL;DR: The calculations provide an explanation for the experimentally observed change in the value of the magnetic exchange through the dmpz ligand when the halide ion is changed from bromide to chloride, and for the very small change observed in the exchangethrough the different halide ions themselves via a combination of changes in geometry, bond lengths, and anion volume.
Journal ArticleDOI
Bimetallic Complexes Supported by a Redox-Active Ligand with Fused Pincer-Type Coordination Sites.
TL;DR: The coordination chemistry of a novel pentadentate ligand (L(N3O2) that provides two closely spaced NNO pincer-type compartments fused together at a central diarylamido unit is described.
Journal ArticleDOI
Initial members of the family of molecular mid-valent high-nuclearity iron nitrides : [Fe4N2X10]4- and [Fe10N8x12]5- (X = Cl-, Br-)
TL;DR: Current theoretical and experimental evidence points toward X = N as the identity of the interstitial atom in the [MoFe7S9X] core of the iron-molybdenum cofactor cluster of nitrogenase, which raises a question as to the existence of a family of molecular iron nitrides of higher nuclearity than known dinuclear Fe(III,IV) species with linear [Fe-N-Fe]5+,4+ bridges.
Journal ArticleDOI
Theoretical investigation of intramolecular magnetic interaction through an ethylenic coupler.
TL;DR: It is shown that an ethylenic coupler provides a very strong intramolecular magnetic interaction and the broken symmetry approach yields a coupling constant -541 K that is in good agreement with the observed value in solid state.
Journal ArticleDOI
Odd electrons and covalent bonding in fullerenes
TL;DR: In this paper, the electronic structure of X60 molecules (XC, Si) was considered in terms of 60 odd electrons and the spin-dependent interaction between them, and conditions for the electrons to be excluded from the covalent pairing were discussed.
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.