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  • 1
    Electronic Resource
    Electronic Resource
    Simple mechanical model for molecular geometry based on the Hellmann-Feynman theorem. I. General principles and applications to AH2, AH3, AH4, AB2, HAB, and ABC molecules (1974)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 96 (1974), S. 2030-2044 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00814a009
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  • 2
    Electronic Resource
    Electronic Resource
    Simple mechanical model for molecular geometry based on the Hellman-Feynman theorem. II. HAAH, BAAB, AB3, H2AB, and B2AC molecules (1974)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 96 (1974), S. 2044-2053 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00814a010
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  • 3
    Electronic Resource
    Electronic Resource
    Direct ab initio calculation of ground-state electronic energies and densities for atoms and molecules through a time-dependent single hydrodynamical equation (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 6229-6239 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: By using an imaginary-time evolution technique, coupled with the minimization of an expectation value, ground-state electron densities and energies have been directly calculated for six atomic and molecular systems (He, Be++, Ne, H2, HeH+, He2++), from a single time-dependent (TD) quantum fluid dynamical equation of motion whose real-time solution yields the TD electron density. For all the systems, a local Wigner-type correlation functional has been employed. For Ne, a local exchange functional is used while, for all the other systems, the exchange energy is calculated exactly. The static (ground-state) results are of beyond-Hartree–Fock quality for all the species. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478527
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  • 4
    Electronic Resource
    Electronic Resource
    Density functional calculation for doubly excited autoionizing states of helium atom (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 5892-5897 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Several doubly excited autoionizing states of He have been calculated within the density functional framework by employing the Harbola–Sahni exchange potential. Correlation effects have been incorporated in the total effective potential through a Wigner-type correlation potential. Although continuum functions are not explicitly incorporated into these calculations, resonance energies of these states are in satisfactory agreement with other theoretical results. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471321
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  • 5
    Electronic Resource
    Electronic Resource
    Theory of hopping transport of holes in amorphous SiO2 (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5248-5255 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A quantum-mechanical theory of hole transport in SiO2 is developed based on modeling of the oxide as an array of time-dependent δ-function potential well distribution. Holes undergo a variable range hopping transport which is dispersive in nature. The oxide, being an insulator, involves a maximum cutoff phonon frequency of 1014–1015 s−1. The Schrödinger equation is solved along with the Poisson equation using a piecewise linear internal field. The theory is applied to metal-oxide-semiconductor structures subjected to a short radiation pulse. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359276
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  • 6
    Electronic Resource
    Electronic Resource
    Comments on the correlation between the Weizsäcker correction and the binding energy of diatomic molecules (1986)
    Springer
    Theoretical chemistry accounts 69 (1986), S. 259-263 
    Details
    ISSN: 1432-2234
    Keywords: Weizsäcker correction ; Binding energy ; Diatomic molecules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Using the double-zeta wavefunctions of Snyder and Basch [5], the Weizsäcker correction $$T_w = \tfrac{1}{8}\int d \vec r(\nabla \rho \cdot \nabla \rho )\rho ^{ - 1} $$ has been evaluated for the molecules H2, HF, BF, N2 and CO. There was no linear correlation between T w and the binding energy for these molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00526424
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  • 7
    Electronic Resource
    Electronic Resource
    A density-functional calculation of dynamic dipole polarizabilities of noble gas atoms (1983)
    Springer
    Theoretical chemistry accounts 62 (1983), S. 209-217 
    Details
    ISSN: 1432-2234
    Keywords: Density-functional theory ; Dynamic polarizability ; Noble gas atoms ; Variation-perturbation method ; Direct density calculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Using a very simple trial function and unperturbed electron densities calculated by a new procedure, the frequency-dependent dipole polarizability α (ω) of Ne, Ar, Kr and Xe has been calculated in the range 0 ≤ ω ≤ 0.45 a.u., by a Karplus-Kolker-type variation-perturbation method. Results progressively worsen for larger systems so that, for Xe, α(0) is only 75% of the experimental value. Probable reasons for this are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00548835
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  • 8
    Electronic Resource
    Electronic Resource
    A density-functional calculation of dynamic dipole polarizabilities of noble gas atoms (1985)
    Springer
    Theoretical chemistry accounts 68 (1985), S. 336-336 
    Details
    ISSN: 1432-2234
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00527542
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  • 9
    Electronic Resource
    Electronic Resource
    Femtosecond quantum fluid dynamics of helium atom under an intense laser field (1998)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 70 (1998), S. 441-474 
    Details
    ISSN: 0020-7608
    Keywords: quantum fluid dynamics ; atom-laser interaction ; femtosecond dynamics ; density functional theory ; high harmonic generation ; Chemistry ; Theoretical, Physical and Computational Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A comprehensive, nonperturbative, time-dependent quantum mechanical (TDQM) approach is proposed for studying the dynamics of a helium atom under an intense, ultrashort (femtoseconds) laser pulse. The method combines quantum fluid dynamics (QFD) and density functional theory. It solves a single generalized nonlinear Schrödinger equation of motion (EOM), involving time and three space variables, which is obtained from two QFD equations, namely, a continuity equation and an Euler-type equation. A highly accurate finite difference scheme along with a stability analysis is presented for numerically solving the EOM. Starting from the ground-state Hartree-Fock density for He at t=0, the EOM yields the time-dependent (TD) electron density, effective potential surface, difference density, difference effective potential, ground-state probability, 〈r〉, magnetic susceptibility, polarizability, flux, etc. By a Fourier transformation of the TD dipole moment along the linearly polarized-field direction, the power and rate spectra for photoemission are calculated. Eleven mechanistic routes for photoemission are identified, which include high harmonic generation as well as many other spectral transitions involving ionized, singly excited, doubly excited (autoionizing), and continuum He states, based on the evolution of the system up to a particular time. Intimate connections between photoionization and photoemission are clearly observed through computer visualizations. Apart from being consistent with current experimental and theoretical results, the present results offer certain predictions on spectral transitions which are open to experimental verification.   © 1998 John Wiley & Sons, Inc. Int J Quant Chem 70: 441-474, 1998
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New method for the direct calculation of electron density in many-electron systems. I. Application to closed-shell atoms (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1-26 
    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: A new density-functional equation is suggested for the direct calculation of electron density ρ(r) in many-electron systems. This employs a kinetic energy functional T2 + f(r)T0, where T2 is the original Weizsäcker correction, T0 is the Thomas-Fermi term, and f(r) is a correction factor that depends on both r and the number of electrons N. Using the Hartree-Fock relation between the kinetic and the exchange energy density, and a nonlocal approximation to the latter, the kinetic energy-density functional is written (in a.u.) \documentclass{article}\pagestyle{empty}\begin{document}$$ t[\rho] = {\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 4}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$4$}}\nabla ^2 \rho + {\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 8}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$8$}}(\nabla \rho \cdot \nabla \rho)/\rho + C_k f({\bf r})\rho ^{5/3}, $$\end{document} where \documentclass{article}\pagestyle{empty}\begin{document}$ C_k = {\raise0.7ex\hbox{$2$} \!\mathord{\left/ {\vphantom {2 {10}}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{${10}$}}(3\pi ^2)^{2/3} $\end{document}. Incorporating the above expression in the total energy density functional and minimizing the latter subject to N representability conditions for ρ(r) result in an Euler-Lagrange nonlinear second-order differential equation \documentclass{article}\pagestyle{empty}\begin{document}$$ \left[{ - {\raise0.7ex\hbox{$1$} \!\mathord{\left/ {\vphantom {1 2}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$2$}}\nabla ^2 + v_{{\rm nuc}} ({\bf r}) + v_{{\rm cou}} ({\bf r}) + v_{XC} ({\bf r}) + {\raise0.7ex\hbox{$5$} \!\mathord{\left/ {\vphantom {5 3}}\right.\kern-\nulldelimiterspace}\!\lower0.7ex\hbox{$3$}}C_k g({\bf r})\rho ^{2/3}} \right]\phi ({\bf r}) = \mu \phi ({\bf r}) $$\end{document} where μ is the chemical potential, we have ρ(r) = |φ(r)|2, and g(r) is related to f(r). Numerical solutions of the above equation for Ne, Ar, Kr, and Xe, by modeling f(r) and g(r) as simple sums over Gaussians, show excellent agreement with the corresponding Hartree-Fock ground-state densities and energies, indicating that this is likely to be a promising method for calculating fairly accurate electron densities in atoms and molecules.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230104
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