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  • 1
    Electronic Resource
    Electronic Resource
    Electronegativities, electron affinities, ionization potentials, and hardnesses of the elements within spin polarized density functional theory (1984)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 106 (1984), S. 3723-3727 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00325a003
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  • 2
    Electronic Resource
    Electronic Resource
    An exchange energy functional based on the Dirac and the Fermi–Amaldi approximations (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 7188-7192 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The exchange energy density functional of an N electron atom is approximated by a combination of the Dirac and the Fermi–Amaldi approximations. The unknown coefficients of the combination are estimated by requiring that the sum of the Coulombic and exchange energies vanish when evaluated with the exact one-electron density. Evaluating the present functional with the Hartree–Fock densities of 1785 atoms and ions, and comparing the resulting exchange energies with the corresponding Hartree–Fock values gave an average error of 2%. The functional derivative has the correct long-range behavior, and leads to an Euler–Lagrange equation whose solutions gave energies which were in very good agreement with the Hartree–Fock values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451354
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  • 3
    Electronic Resource
    Electronic Resource
    A virial expansion of the pressure in a quantum system within the local thermodynamic transcription of density functional theory (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 7245-7250 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The concept of local pressure in an electronic system is extended and developed, starting from an integral relation of Bartolotti and Parr (Ref. 11) and using the local thermodynamic language of Ghosh, Berkowitz, and Parr (GBP) (Ref. 3), who have shown that for an ideal, noninteracting microscopic system the internal pressure at a point r is purely kinetic and given by ps=ρ(r)kT˜(r), where T˜(r) is an appropriately defined local temperature. In the present paper, we show that this equation, exact for the noninteracting, ideal system within the local thermodynamic transcription is a first order truncation of the real, interacting system pressure density functional, which contains explicit correlation and exchange pressure contributions, which act as "deviations from ideality'' in the real system. From analogy with the macroscopic situation, the pressure density functional is written as a virial expansion in terms of the density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451362
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  • 4
    Electronic Resource
    Electronic Resource
    Theoretical study of the reactive intermediate Si2Me4[(η5-C5H4) Fe(CO)2] 2 2− (1994)
    Springer
    Journal of inorganic and organometallic polymers and materials 4 (1994), S. 79-84 
    Details
    ISSN: 1572-8870
    Keywords: Theoretical ; extended Huckel ; molecular mechanics ; silyl organometallic complexes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In two previous papers (Kinget al., J. Organomet. Chem. 19, 327, 1969; Pannellet al., Organometallics 9, 859, 1990), the synthesis and X-ray structure of the two tetramethyl disilyl complexes [(η5-C5H5) Fe(CO)2]2Si2Me4 (I) and Si2Me4[(η5-C5H4) Fe(CO)2CH3]2 (II) were reported. ComplexII is obtained fromI [2]. However, attempts to form other derivatives fromI have generally failed. In the chemical process to getII fromI, an intermediate complex, Si2Me4[(η5-C5H4) Fe(CO)2] 2 2− (III), is probably formed. This is similar to complexII without the two methyl groups bonded to the Fe atoms. Therefore, a theoretical study that may shed some light on the intermediate structure, stability, and reactivity is justified. We have developed theoretical studies consisting of extended Huckel electronic structure calculations on the simulated intermediate geometry. The results obtained from these calculations suggest that it might be stable enough to form during reactions of complexI. The more reactive sites, which suggest reaction alternatives, are pointed out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00684029
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  • 5
    Electronic Resource
    Electronic Resource
    Local hardness revisited: Definition and the spin-polarized Kohn-Sham formulation of density functional theory (1994)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 49 (1994), S. 159-169 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The definition of local hardness is clarified within the Kohn-Sham formulation of the density functional theory. Exact equations for the local hardness of open- and closed-shell electronic systems are derived. It is found that the Kohn-Sham independent particle kinetic energy does not contribute to local hardness. The apparent contradiction with previous work of Parr et al. is cleared up when the local hardness definition is revised. © 1994 John Wiley & Sons, Inc.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560490308
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  • 6
    Electronic Resource
    Electronic Resource
    On the conjoint gradient correction to the Hartree - Fock kinetic and exchange energy density functionals (1996)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 57 (1996), S. 3-6 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetic and the exchange energy functionals are expressed in the form T[ρ] = CTF∫ drρ5/3(r)ft(s) and K[ρ] = CD∫ drρ4/3(r)fK(s), where CTF = (3/10)(3π2)2/3 and CD = -(3/4)(3/π)4/3 are the Thomas-Fermi and the Dirac coefficients, respectively, and s = |∇ρ(r)|/Csρ4/3(r), with Cs = 2(3π2)1/3. These expressions are used to perform a comparison of fT(s) and fK(s) in terms of their generalized gradient expansion approximations. It is shown that fκ(s) and is congruent to fT(s) in the range characteristic of the interior regions of atoms and many solids and that the second-order gradient expansion of the kinetic energy provides a rather reasonable approximation to the generalized gradient expansion approximation of both the kinetic and the exchange energy functionals. © 1996 John Wiley & Sons, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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