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
DFT Calculations for Intermediate and Active States of the Diiron Center with a Tryptophan or Tyrosine Radical in Escherichia coli Ribonucleotide Reductase
Wen-Ge Han,Louis Noodleman +1 more
TL;DR: Proton-coupled and simple redox potential calculations show that the kinetic control of proton transfer to Tyr122(•) plays a critical role in preventing reduction from the active Fe(III)Fe(III)-Tyr122( •) state to the met state, which is potentially the reason why Tyr122 in the active state can be stable over a very long period.
Journal ArticleDOI
DFT calculations of comparative energetics and ENDOR/Mössbauer properties for two protonation states of the iron dimer cluster of ribonucleotide reductase intermediate X
Wen-Ge Han,Louis Noodleman +1 more
TL;DR: Two models for the active site structure of class-I ribonucleotide reductase (RNR) intermediate X in subunit R2 have been studied using broken-symmetry density functional theory incorporated with the conductor like screening (COSMO) solvation model and with the finite-difference Poisson-Boltzmann self-consistent reaction field (PB-SCRF) calculations.
Journal ArticleDOI
Are Spin-Forbidden Crossings a Bottleneck in Methanol Oxidation?
TL;DR: In this article, the rate of spin-surface crossing from the singlet to the triplet potential energy surface during methanol oxidation has been examined for classically spin-forbidden crossings.
Journal ArticleDOI
Reaching optimal light-induced intramolecular spin alignment within photomagnetic molecular device prototypes.
TL;DR: Ground-state and excited-state properties of novel photomagnetic molecular devices (PMMDs) are investigated by means of density functional theory and the choice of 2-pyrimidinyl (pm) as B elements to replace the original p-phenylene (ph) is chosen.
Journal ArticleDOI
Reactivity of titanium dimer and molecular nitrogen in rare gas matrices. Vibrational and electronic spectra and structure of Ti2N2
TL;DR: The results show that the in situ formation results from the spontaneous reaction at 9 K of ground state Ti2 with N2, and that several low-lying excited states of Ti2N2 are also observed between 0.78 and 1.1 eV above the ground state.
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.