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
Density-functional study of the Cr 8 antiferromagnetic ring
TL;DR: In this paper, an ab initio characterization of the electronic and magnetic properties of the molecular ring of the Cr 8$ molecular ring has been presented, and it has been shown that the Cr atoms attain a local spin moment of Ω(3.2) and that the preferred arrangement of Cr atoms in the ground state is antiferromagnetic.
Journal ArticleDOI
Combining experimental and theoretical methods to learn about the reactivity of gas-processing metalloenzymes
Claudio Greco,Vincent Fourmond,Carole Baffert,Po-hung Wang,Sébastien Dementin,Patrick Bertrand,Maurizio Bruschi,Jochen Blumberger,Luca De Gioia,Christophe Léger +9 more
TL;DR: Karplus et al. as mentioned in this paper discuss the interplay between the information obtained from theoretical and experimental methods, by focussing on enzymes that process small molecules such as H2 or CO2 (hydrogenases, CO-dehydrogenase and carbonic anhydrase).
Journal ArticleDOI
Electronic Structures of “Low-Valent” Neutral Complexes [NiL2]0 (S = 0; L = bpy, phen, tpy) – An Experimental and DFT Computational Study
TL;DR: The electronic structures of the neutral complexes [Ni(bpy)2]0, [Ni[tpy]2] 0, Ni(tpy)0, and Ni(phen)0) have been investigated by a combination of UV/Vis spectroscopy, magnetochemistry, and X-ray crystallography.
Book ChapterDOI
Dealing with Complexity in Open-Shell Transition Metal Chemistry from a Theoretical Perspective: Reaction Pathways, Bonding, Spectroscopy, And Magnetic Properties
Frank Neese,William Ames,Gemma J. Christian,Mario Kampa,Dimitrios G. Liakos,Dimitrios A. Pantazis,Michael Roemelt,Panida Surawatanawong,Y.E. Shengfa +8 more
TL;DR: In this article, the authors illustrate the challenges that are met in theoretical transition metal chemistry: reactivity of high-valent iron-oxo sites and the challenge of multiple spin-state channels; treatment of magnetic spectroscopic observables in the case of (near) orbital degeneracy; experimentally validated description of transition metal complexes with coordinated ligand radicals; calculation of the magnetic properties of oligonuclear transition metal clusters with applications to Photosystem II.
Journal ArticleDOI
Theory of chemical bonds in metalloenzymes III: Full geometry optimization and vibration analysis of ferredoxin-type [2Fe–2S] cluster
Mitsuo Shoji,Kenichi Koizumi,Takeshi Taniguchi,Yasutaka Kitagawa,Shusuke Yamanaka,Mitsutaka Okumura,Kizashi Yamaguchi +6 more
TL;DR: In this paper, the nature of chemical bonds in a ferredoxin-type [2Fe-2S] cluster has been investigated on the basis of natural orbitals and several bond indices developed in Parts I and II of this study.
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.