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  • 1
    Electronic Resource
    Electronic Resource
    Electron correlation in weakly coupled transition metal dimers: Bimetallocenylenes and bimetallocenes (1981)
    Springer
    Theoretical chemistry accounts 60 (1981), S. 233-268 
    Details
    ISSN: 1432-2234
    Keywords: Hartree-Fock instabilities ; Electron correlation in binuclear transition metal compounds ; INDO calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Hartree-Fock (HF) instabilities in a series of bimetallocenes (1) and bimetallocenylenes (2) with Fe, Co, Ni and Cr as 3d centers have been investigated by means of a semiempirical INDO Hamiltonian. The HF picture is only valid in the case of the iron dimers. Strong correlation effects are encountered in the Co, Ni and Cr complexes. The necessary conditions for singlet, non-singlet (triplet) and non-real variations of the HF orbitals are discussed in detail. Singlet fluctuations are the result of intraatomic angular correlation (short-range) at each 3d center. The violation of the spin symmetry corresponds to a long-range interaction between the transition metal centers. Only for MOs with large 3d xz amplitudes there exists a channel for the interatomic spin decoupling. Consequences for polymetallocenes are shortly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02394726
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The electronic structures of some extended conjugated electron acceptors within the Hartree-Fock approximation and beyond the mean-field approach as verified by the Hartree-Fock instabilities (1984)
    Springer
    Theoretical chemistry accounts 66 (1984), S. 51-64 
    Details
    ISSN: 1432-2234
    Keywords: Extended conjugated electron acceptors ; electronic structure in the INDO and π-electronic approximations ; Hartree-Fock instabilities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The electronic structures of the extended conjugated electron acceptors1–3 were investigated within the framework of a semiempirical INDO and a π-electronic Hartree-Fock Hamiltonian. Utilizing Koopmans' theorem, predictions are made of the magnitude of the ionization potentials and the electron affinities and their dependence on the molecular geometry (“olefinic” vs. “aromatic”) and the nature of the acceptor functions. The validity of the Hartree-Fock approximation has been studied by means of the Thouless stability conditions. The INDO and π-SCF wave functions turn out to be adequate descriptions of the ground states of1–3. A single particle hole pair, due to a small energy separation between the highest occupied and lowest virtual orbital and a large Coulomb integral with respect to these orbitals leads to non-singlet (triplet) instabilities or near instabilities of the wave functions indicating the importance of spin correlation in1–3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00577139
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electron correlation in weakly coupled transition metal dimers: Bimetallocenylenes and bimetallocenes (1981)
    Springer
    Theoretical chemistry accounts 60 (1981), S. 233-268 
    Details
    ISSN: 1432-2234
    Keywords: Hartree-Fock instabilities ; Electron correlation in binuclear transition metal compounds ; INDO calculations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The Hartree-Fock (HF) instabilities in a series of bimetallocenes (1) and bimetallocenylenes (2) with Fe, Co, Ni and Cr as 3d centers have been investigated by means of a semiempirical INDO Hamiltonian. The HF picture is only valid in the case of the iron dimers. Strong correlation effects are encountered in the Co, Ni and Cr complexes. The necessary conditions for singlet, non-singlet (triplet) and non-real variations of the HF orbitals are discussed in detail. Singlet fluctuations are the result of intraatomic angular correlation (short-range) at each 3d center. The violation of the spin symmetry corresponds to a long-range interaction between the transition metal centers. Only for MOs with large 3d xz amplitudes there exists a channel for the interatomic spin decoupling. Consequences for polymetallocenes are shortly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00553747
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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