1,096 research outputs found

    Exact energy of the spin-polarized two-dimensional electron gas at high density

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    We derive the exact expansion, to O(rs)O(r_s), of the energy of the high-density spin-polarized two-dimensional uniform electron gas, where rsr_s is the Seitz radius.Comment: 7 pages, 1 figure and 1 table, submitted to Phys. Rev.

    Gozintographs for By-Products and Cyclic Production: An Approach for ERP System Application

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    Advanced Information Technology Application in ERP Systems

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    Current Enterprise Resource Planning Systems (ERP) are used to track companies’ finances, human resources, and logistics. Upcoming market-driven requirements focus on outside connectivity and up-to-date information supply, including business-to-business support, e-commerce, and virtual enterprises. How can these requirements be met by applying emerging information technologies? This paper focuses on future development of ERP systems emphasizing on technical aspects of information technology application as enabler. It briefly discusses existing research approaches and potential research and development issues

    Specifying Business Components in Virtual Engineering Communities

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    Chemistry in One Dimension

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    We report benchmark results for one-dimensional (1D) atomic and molecular systems interacting via the Coulomb operator ∣x∣−1|x|^{-1}. Using various wavefunction-type approaches, such as Hartree-Fock theory, second- and third-order M{\o}ller-Plesset perturbation theory and explicitly correlated calculations, we study the ground state of atoms with up to ten electrons as well as small diatomic and triatomic molecules containing up to two electrons. A detailed analysis of the 1D helium-like ions is given and the expression of the high-density correlation energy is reported. We report the total energies, ionization energies, electron affinities and other interesting properties of the many-electron 1D atoms and, based on these results, we construct the 1D analog of Mendeleev's periodic table. We find that the 1D periodic table contains only two groups: the alkali metals and the noble gases. We also calculate the dissociation curves of various 1D diatomics and study the chemical bond in H2+_2^+, HeH2+^{2+}, He23+_2^{3+}, H2_2, HeH+^+ and He22+_2^{2+}. We find that, unlike their 3D counterparts, 1D molecules are primarily bound by one-electron bonds. Finally, we study the chemistry of H3+_3^+ and we discuss the stability of the 1D polymer resulting from an infinite chain of hydrogen atoms.Comment: 27 pages, 7 figure

    Uniform Electron Gases. II. The Generalized Local Density Approximation in One Dimension

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    We introduce a generalization (gLDA) of the traditional Local Density Approximation (LDA) within density functional theory. The gLDA uses both the one-electron Seitz radius \rs and a two-electron hole curvature parameter η\eta at each point in space. The gLDA reduces to the LDA when applied to the infinite homogeneous electron gas but, unlike the LDA, is is also exact for finite uniform electron gases on spheres. We present an explicit gLDA functional for the correlation energy of electrons that are confined to a one-dimensional space and compare its accuracy with LDA, second- and third-order M{\o}ller-Plesset perturbation energies and exact calculations for a variety of inhomogeneous systems.Comment: 26 pages, 2 figures, accepted for publication in Journal of Chemical Physic
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