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  • 1
    Electronic Resource
    Electronic Resource
    Electron densities in momentum and position spaces. II. Application of density mapping to the helium ground state (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 4758-4762 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The recently proposed method of density mapping between momentum and position spaces is applied to the ground state of the helium atom. The Kellner densities and wave functions are used as reference, and the Eckart densities γ(p) and ρ(r) are employed as test densities keeping their parent wave functions in blind. From the momentum density γ(p), the corresponding position density ργ(r) and the position moments 〈rn〉γ (−2≤n≤4) are generated within a few percent error. The inverse procedure generates the momentum density γρ(p) and the momentum moments 〈pn〉ρ (−2≤n≤4) from the position density ρ(r) with a better accuracy. Density-functional calculations are performed in a simplified manner and the energies close to the Hartree–Fock limit value are obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456764
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  • 2
    Electronic Resource
    Electronic Resource
    Spin-polarized density functional calculations based on local scaling transformations (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 2910-2914 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The recently proposed method for practical density functional calculations is extended to the spin-decomposed electron densities. From given α- and β-spin electron densities ρα(r) and ρβ(r), local scaling transformations are used to generate their possible parent wave function Ψρ({xi}), where xi=(ri,σi) is the combined position-spin coordinate of electron i. The energy E[ρα,ρβ] associated with the given spin-decomposed densities is then defined as the Hamiltonian expectation value over the generated wave function Ψρ({xi}), and the densities ρα and ρβ are determined so as to minimize the energy functional E[ρα,ρβ]. An illustrative application is given for the ground-state Li atom within the unrestricted Hartree–Fock framework.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459812
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  • 3
    Electronic Resource
    Electronic Resource
    Electron densities in momentum and position spaces. I. Mapping relation and density functional aspect (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 1108-1113 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Based on the theory of point transformations, a possible exact relationship between the atomic electron densities in momentum and position spaces is studied through the inverse mapping from the electron density to the N-electron wave function with an appropriate generator or reference N-electron wave function. The results are used to construct the ground-state energy density functional of atoms in momentum space.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457183
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  • 4
    Electronic Resource
    Electronic Resource
    Hydrogen bonding in benzonitrile–water complexes (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 833-841 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The hydrogen bonding between benzonitrile and one and two water molecules is studied ab initio by means of a hybrid B3LYP density functional in conjunction with 6-31+G(d,p) and aug-cc-pVDZ basis sets. The strength of such hydrogen bonding is analyzed in terms of a magnitude of "window region" appearing in the infrared spectra of the studied complexes and experimentally measurable and also in terms of the shifts of the stretching mode of the triple CN bond of benzonitrile. The lower-energy portions of the potential energy surfaces in the neighborhoods of the stable complexes of benzonitrile with one and two water molecules are fully determined, and implications of their landscape on the large-amplitude dynamics of the water moiety around benzonitrile and comparison with experiments are elaborated. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1371516
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  • 5
    Electronic Resource
    Electronic Resource
    Another look at the electron attachment to nitrous oxide (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 114 (2001), S. 7911-7917 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ab initio molecular orbital calculations up to the coupled-cluster level with the aug-cc-pVQZ basis set allowed us to have a new look at the electron affinity of nitrous oxide (N2O) resulting in a detection of a new N2O− entity, and thereby a novel mechanism for the dissociative electron attachment process, N2O+e−→N2+O−. Addition of an electron to the linear N2O ground state (X 1Σ+) leads first to an open-chain bound anion which lies 25 kJ/mol above the neutral. Upon a cyclization of the open anion with an additional energy barrier of 25 kJ/mol, a cyclic anionic species is formed which is more stable than the open isomer and lies now, at most, 3 kJ/mol above the neutral ground state (the transition structure for cyclization being 50 kJ/mol above neutral N2O). The cyclic anionic species constitutes a weak complex between N2 and O− characterized by a binding energy of only 16 kJ/mol. The electronic structure of the anion complex is analyzed, a number of earlier experimental results are clarified and a resolution for the long-standing disagreement between experiment and theory around the electron affinity of N2O is proposed. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1364679
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  • 6
    Electronic Resource
    Electronic Resource
    Local-scaling transformations and the direct determination of Kohn–Sham orbitals and potentials for beryllium (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 318-326 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Local-scaling transformations are used in the present work to obtain accurate Kohn–Sham 1s and 2s orbitals for the beryllium atom by means of a density-constrained variation of the single-determinant kinetic energy functional. An analytic representation of these Kohn–Sham orbitals is given and the quality of the different types of orbitals generated is discussed with particular reference to their kinetic energy and momenta mean values. In addition, we determine the effective Kohn–Sham potential and analyze it in terms of its exchange-only and correlation contributions. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469405
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  • 7
    Electronic Resource
    Electronic Resource
    Formulation of N- and v-representable density functional theory. VIII. Relationship between the density-driven and the local-scaling versions (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 9054-9059 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: It is shown that Cioslowski's density-driven construction of one-particle orbitals corresponds to a finite basis representation of local-scaling transformations. Implications of this correspondence, with respect to the formulation and implementation of a variational principle for the density, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.461184
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  • 8
    Electronic Resource
    Electronic Resource
    On classical theory of moments: Finite-set-of-moments approach. I. Non-negative distribution: Its even moments and Hankel transform (1987)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 28 (1987), S. 8-14 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: For an unknown non-negative distribution Ω(z), the corresponding Hankel transform F(k) is introduced. It is proposed to partition F(k) in such a way that each component satisfies a linear differential relation whose solution gives an approximate Hankel transform in terms of a given finite set of even moments. As a result, for a known finite set of even moments, the non-negative distribution Ω(z) is obtained in the form of a finite sum of the definite differential and integral forms of the Gaussian distributions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.527758
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  • 9
    Electronic Resource
    Electronic Resource
    Quenching of Li (2P) by H2: potential energy surfaces, conical intersection seam, and diabatic bases (1998)
    Springer
    Theoretical chemistry accounts 100 (1998), S. 154-170 
    Details
    ISSN: 1432-2234
    Keywords: Key words: Electronic quenching ; Nonadiabatic coupling ; Diabatic states ; Conical intersection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract. The quenching of Li (1s 22p; 2P) to Li (1s 22s; 2S) by H2 is considered using coupled-cluster and multireference configuration-interaction techniques. C 2 v (2A1, 2B2) and C ∞ v (2Π,2Σ+) sections of the 12A′ and 22A′ potential energy surfaces are determined. The C 2 v portion of the 12A′−22A′ seam of conical intersection is studied. Perhaps the most significant finding is a surprising trifurcation of this seam into a portion with only C s symmetry and the aforementioned C 2 v portion. The adiabatic-to-diabatic state transformation is considered in the vicinity of the seam of conical intersection using both perturbation theory and the dipole moment operator. The 2B2 section of the 22A′ potential energy surface exhibits an exciplex in the general vicinity of the seam of conical intersection. The 2Π section of the 22A′ potential energy surface possesses a global minimum lying 1.86kcal/mol below the Li (2P)+H2 asymptote. A van der Waals-like minimum with C ∞ v symmetry was found on the 12A′ potential energy surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002140050376
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  • 10
    Electronic Resource
    Electronic Resource
    Formulation ofN- and υ-representable density functional theory. III: Excited states (1992)
    Springer
    Journal of mathematical chemistry 11 (1992), S. 325-339 
    Details
    ISSN: 1572-8897
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mathematics
    Notes: Abstract The local-scaling transformation version of density functional theory is extended to the treatment of excited states. This is accomplished in the context of the super-particle formulation of Katriel [Int. J. Quant. Chem. 23(19$3)1767]. It is shown that for a given superparticle generating wave function, the energy density functional corresponding to the excited-state super-system may be explicitly constructed. The derivation of an Euler-Lagrange equation for the composite excited-state density is discussed. A preliminary calculation for the 21S state of helium is reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01164212
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