CALCULATIONS OF CHEMISORPTION OF HYDROGEN AND NITROGEN ON TITANIUM USING X-ALPHA-SW AND SCF-CI METHODS.
Item
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Title
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CALCULATIONS OF CHEMISORPTION OF HYDROGEN AND NITROGEN ON TITANIUM USING X-ALPHA-SW AND SCF-CI METHODS.
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Identifier
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AAI8312354
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identifier
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8312354
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Creator
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HUNG, SING-CHANG.
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Contributor
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C. Rutherford Fischer
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Date
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1983
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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
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Abstract
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Two theoretical studies are used as examples of chemisorption on transition metal surfaces. The first calculation employs the SCF-X(alpha)-SW method to determine the electronic structures of several close-packed Ti-Ti and Ti-H systems. The relative importance of Ti s, p, and d electron bonding to its Ti neighbors and to H are reported. The roles of the d electrons in the Ti-Ti and Ti-H bond are discussed. The effect of the presence of an H atom on the first few layers of the metal is also studied. The second set of calculations employs the Hartree-Fock-Roothaan SCF formulation supplemented by configuration-interaction (CI) to determine the energetics of adsorption of an N(,2) molecule at a Ti surface. These calculations are made tractable by using a Ti core potential and by a unitary localization transformation to define a local surface region of localized lattice plus adsorbate orbitals. The results show that an underlayer of N atoms forms at the octahedral sites. The calculated adsorption energy of 115 kcal/mole compares favorably with experiment. Binding energy contributions in the several successive steps of the calculations are discussed. Eigenvalue spectra for the selected lattice-adsorbate geometries are compared to the UPS experimental data.
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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.
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Program
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Physics
