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
Mössbauer, Electron Paramagnetic Resonance, and Density Functional Theory Studies of Synthetic S = 1/2 FeIII−O−FeIV═O Complexes. Superexchange-Mediated Spin Transition at the FeIV═O Site
Raymond F De Hont,Genqiang Xue,Michael P. Hendrich,Lawrence Que,Emile L. Bominaar,Eckard Münck +5 more
TL;DR: Electron paramagnetic resonance (EPR) and Mössbauer studies show that both complexes have an S = 1/2 ground state which results from antiferromagnetic coupling of the spins of a high-spin (S(a) = 5/2) Fe(III) and a high(b) = 2)Fe(IV) site, and the exchange coupling constant J is determined to be 90 ± 20 cm(-1) for both 1-OH and 1-
Journal ArticleDOI
Electron-Rich, Diiron Bis(monothiolato) Carbonyls: C-S Bond Homolysis in a Mixed Valence Diiron Dithiolate.
Qian-Li Li,Noémie Lalaoui,Toby J. Woods,Thomas B. Rauchfuss,Federica Arrigoni,Giuseppe Zampella +5 more
TL;DR: DFT calculations predict that the homolysis of a C-S bond is exergonic for [Fe2(SCH2Ph) 2(CO)2(PR3)4]+ but endergonicfor the neutral complex as well as less substituted cations.
Journal ArticleDOI
Unraveling the Mechanisms of the Selective Oxidation of Methanol to Formaldehyde in Vanadia Supported on Titania Catalyst
TL;DR: In this paper, a computational study based on B3LYP calculations was carried out to investigate the kinetic and mechanistic aspects of the selective oxidation of methanol to formaldehyde using titania-supported vanadate as a catalyst model.
Journal ArticleDOI
Density Functional Theory Study on the Mechanism of the Reductive Cleavage of CO2 by a Bis-β-Diketoiminatediiron Dinitrogen Complex
Alireza Ariafard,Alireza Ariafard,Nigel J. Brookes,Robert Stranger,Peter D. W. Boyd,Peter D. W. Boyd,Brian F. Yates +6 more
TL;DR: The results show that the insertion of CO(2) into the di iron complex is the rate determining step of the reductive cleavage reaction, and further reaction of the released CO with the starting diiron complex is also predicted to be strongly exergonic.
Journal ArticleDOI
Accurate yet feasible post-Hartree–Fock computation of magnetic interactions in large biradicals through a combined variational/perturbative approach: Setup and validation
TL;DR: The results obtained for model diradical species which exhibit ferromagnetic and antiferromagnetic coupling are fully satisfactory and very promising for future applications of the method to larger molecular systems of technological interest in magnetic-based devices.
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.