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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Journal ArticleDOI
Electrostatic effects on proton coupled electron transfer in oxomanganese complexes inspired by the oxygen-evolving complex of photosystem II.
Muhamed Amin,Leslie Vogt,Serguei Vassiliev,Ivan Rivalta,Mohammad M. Sultan,Doug Bruce,Gary W. Brudvig,Victor S. Batista,Marilyn R. Gunner +8 more
TL;DR: The reported study introduces an enhanced multiconformer continuum electrostatics model, parametrized at the density functional theory (DFT) level with a classical valence model for the oxomanganese core, and provides the foundation for analysis of electrostatic effects in other oxomangese complexes and metalloenzymes, where proton coupled electron transfer plays a fundamental role in redox-leveling mechanisms.
Journal ArticleDOI
Heisenberg Exchange in Dinuclear Manganese Complexes: A Density Functional Theory Study.
TL;DR: The obtained results indicate that quantitative agreement with available experimental data for the Heisenberg exchange constants can be achieved for most of the investigated complexes but also that there are significant failures for some compounds.
Journal ArticleDOI
Effects of Substitution on the Singlet−Triplet Energy Splittings and Ground-State Multiplicities of m-Phenylene-Based Diradicals: A Density Functional Theory Study
TL;DR: In this article, the effects of substitution on the singlet−triplet (S−T) energy gaps and the ground-state multiplicities were investigated for a series of m-phenylene-bridged diradicals.
Journal ArticleDOI
Spectroscopic and Electronic Structure Description of the Reduced Binuclear Non-Heme Iron Active Site in Ribonucleotide Reductase from E. coli: Comparison to Reduced Δ9 Desaturase and Electronic Structure Contributions to Differences in O2 Reactivity
TL;DR: Ribonucleotide reductase catalyzes the first committed and rate-determining step in DNA biosynthesis, the reduction of ribonucleotides to deoxyribon nucleotides.
Journal ArticleDOI
The origin of the two-electron/four-centers C--C bond in pi-TCNE(2)2- dimers: electrostatic or dispersion?
TL;DR: The results show that the only minima of this aggregate that preserves the π‐TCNE22− structure has the two K+ atoms placed in equatorial positions in between the two TCNE− planes, and the bond results from the combination of the electrostatic and dispersion components, being the first the dominant one.
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.