Study of electron correlations in non-uniform density systems via the work formalism of electronic structure.
Item
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Title
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Study of electron correlations in non-uniform density systems via the work formalism of electronic structure.
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Identifier
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AAI9605664
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identifier
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9605664
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Creator
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Slamet, Marlina.
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Contributor
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Adviser: Viraht Sahni
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Date
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1995
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Language
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English
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Publisher
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City University of New York.
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Subject
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Physics, Condensed Matter | Physics, Atomic
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Abstract
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In this thesis we investigate electron correlations in nonuniform density systems via the work formalism of electronic structure. In the formalism, which is founded in Schrodinger theory, the system wavefunction is determined by solution of a Sturm-Liouville-type equation over both occupied and virtual states. Both the local potential representing electron correlations in this differential equation as well as the electron interaction energy arise by Coulomb's law from a quantum-mechanical source charge distribution. This source charge is the pair-correlation density. The potential is the work done to move an electron in the force field of the pair-correlation density, whereas the energy is the energy of interaction between the electronic and pair-correlation densities. We have investigated Coulomb correlation effects in the Helium atom in its ground-state by studying the structure of the dynamic Coulomb hole charge distribution as a function of electron position, and the local correlation potential to which it gives rise. These calculations confirm the tenet of the work formalism that the asymptotic structure of the effective potential of all nonuniform density systems in the classically forbidden region is a consequence only of the Pauli exclusion principle, and thus exactly determinable. A comparison of the work formalism correlation potential to the corresponding potential of Kohn-Sham density-functional theory then leads to insights into the structure of the latter. We have also studied electron correlations within the Pauli-correlated approximation in a nonspherically symmetric system as represented by a degenerate state of the Carbon atom. These calculations demonstrate the applicability of the work formalism to such systems without having to invoke the central-field approximation. Finally, we provide insights into electron correlations in the local density approximation of Kohn-Sham theory by rederiving the equations of the approximation via the work formalism. The derivation shows the presence of correlations in addition to those assumed by Kohn-Sham theory, and this constitutes the fundamental physical reason for the success of the approximation. This latter conclusion is confirmed by a study of these correlations by application to the inhomogeneous electron gas in atoms and at metal surfaces.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
