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Electron energy loss spectroscopy of CH/sub 3/N/sub 2/CH/sub 3/ adsorbed on Ni(100), Ni(111), Cr(100), Cr(111)

Description: A study of the adsorption of CH/sub 3/N/sub 2/CH/sub 3/ on Ni(100), Ni(111), Cr(100), and Cr(111) using high resolution electron energy loss spectroscopy (EELS) is presented. Under approximately the same conditions of coverage, the vibrational spectra of CH/sub 3/N/sub 2/CH/sub 3/ on these four surfaces are quite distinct from one another, implying that the CH/sub 3/N/sub 2/CH/sub 3/-substrate interaction is very sensitive to the physical and electronic structure of each surface. In addition to… more
Date: July 1, 1985
Creator: Schulz, M.A.
Partner: UNT Libraries Government Documents Department
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Relativistic heavy ion physics

Description: In 1992 a proposal by the Iowa State University experimental nuclear physics group entitled Relativistic Heavy Ion Physics'' was funded by the US Department of Energy, Office of Energy Research, for a three-year period beginning November 15, 1991. This is a progress report for the first six months of that period but, in order to give a wider perspective, we report here on progress made since the beginning of calendar year 1991. In the first section, entitled Purpose and Trends,'' we give some b… more
Date: January 1, 1992
Creator: Hill, J. C. & Wohn, F. K.
Partner: UNT Libraries Government Documents Department
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Investigations of the potential functions of weakly bound diatomic molecules and laser-assisted excitive Penning ionization

Description: Three variations on the Dunham series expansion function of the potential of a diatomic molecule are compared. The differences among these expansions lie in the choice of the expansion variable, lambda. The functional form of these variables are lambda/sub s/ = l-r/sub e//r for the Simon-Parr-Finlan version, lambda/sub T/ - 1-(r/sub e//r)/sup p/ for that of Thakkar, and lambda/sub H/ = 1-exp(-rho(r/r/sub e/-1) for that of Huffaker. A wide selection of molecular systems are examined. It is found… more
Date: May 1, 1982
Creator: Goble, J.H. Jr.
Partner: UNT Libraries Government Documents Department
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Chemical activation of molecules by metals: Experimental studies of electron distributions and bonding

Description: The formal relationship between measured molecular ionization energies and thermodynamic bond dissociation energies has been developed into a single equation which unifies the treatment of covalent bonds, ionic bonds, and partially ionic bonds. This relationship has been used to clarify the fundamental thermodynamic information relating to metal-hydrogen, metal-alkyl, and metal-metal bond energies. We have been able to obtain a direct observation and measurement of the stabilization energy prov… more
Date: October 1991
Creator: Lichtenberger, Dennis L.
Partner: UNT Libraries Government Documents Department
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Catalytic hydrogenation of carbon monoxide

Description: This project is focused on developing strategies to accomplish the reduction and hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. Our approaches to this issue are based on the recognition that rhodium macrocycles have unusually favorable thermodynamic values for producing a series of intermediate implicated in the catalytic hydrogenation of CO. Observations of metalloformyl complexes produced by reactions of H{sub 2} and CO, and reductive coupling of CO to form… more
Date: December 1, 1992
Creator: Wayland, B.B.
Partner: UNT Libraries Government Documents Department
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Spectroscopic probes of vibrationally excited molecules at chemically significant energies

Description: These experiments apply multiple-laser spectroscopic techniques to investigate the bond energies, potential surface topologies, and dissociation dynamics of highly vibrationally excited molecules. Infrared-optical double resonance pumping of light atom stretch vibrations in H{sub 2}O{sub 2} and HN{sub 3} prepares reactant molecules in single rovibrational states above the unimolecular dissociation threshold on the ground potential surface, and laser induced fluorescence detection of the OH or N… more
Date: March 1, 1992
Creator: Rizzo, T.R.
Partner: UNT Libraries Government Documents Department
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Diosmacycloalkanes as models for the formation of hydrocarbons from surface methylenes

Description: We are making progress on our investigation of the mechanism of olefin exchange with Os{sub 2}(C{sub 2}H{sub 4})(CO){sub 8}. We are probing this system by kinetic study of the reaction of Os{sub 2}(C{sub 2}H{sub 4})(CO){sub 8} with butyl acrylate (BA) under various pressures of ethylene.
Date: May 1, 1992
Creator: Norton, J.R.
Partner: UNT Libraries Government Documents Department
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Surface extended x-ray absorption fine structure of low-Z absorbates using fluorescence detection

Description: Comparison of x-ray fluorescence yield (FY) and electron yield surface extended x-ray absorption fine structure spectra above the S K-edge for c(2 x 2) S on Ni(100) reveals an order of magnitude higher sensitivity of the FY technique. Using FY detection, thiophene (C/sub 4/H/sub 4/S) chemisorption on Ni(100) is studied with S coverages down to 0.08 monolayer. The molecule dissociates at temperatures as low as 100K by interaction with fourfold hollow Ni sites. Blocking of these sites by oxygen l… more
Date: May 1, 1985
Creator: Stoehr, J.; Kollin, E.B.; Fischer, D.A.; Hastings, J.B.; Zaera, F. & Sette, F.
Partner: UNT Libraries Government Documents Department
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Evaluation of the photochemical production of hydrogen from solar energy

Description: The potential for utilizing solar energy through photochemical storage were investigated. Both water and nitrosyl chloride systems are examined. A comprehensive review of the literature led to the conclusion that many major questions must be answered before photochemical energy storage becomes a viable alternate means of exploiting solar energy.
Date: August 9, 1977
Creator: Heppert, J. A.
Partner: UNT Libraries Government Documents Department
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Photogenerated carrier-induced reactions on uhv semiconductor surfaces

Description: The objective for this experimental work was to examine the reaction mechanisms, half-collision dynamics, and other optically induced chemical effects, that are operable on a well characterized single-crystal semiconductor surface. Of particular interest were reactions induced by charge transfer from the semiconductor surface including hot carrier and thermalized carrier processes. The primary technique to measure the desorbed fragment translational energies was time-of-flight mass-spectroscopy… more
Date: May 28, 1992
Creator: Osgood, R.M. Jr.
Partner: UNT Libraries Government Documents Department
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Fundamental studies of catalytic gasification

Description: The major purpose of this project was to finding catalysts which will permit steam gasification of carbonaceous material at reasonable rates and at lower temperatures than currently practiced. This quarter, experiments with steam gasification of graphite were performed. Catalysts studied were potassium, calcium, and nickel oxides. Reaction kinetics are discussed. 28 refs., 34 figs., 8 tabs.
Date: June 1, 1991
Creator: Heinemann, H. & Somorjai, G.A.
Partner: UNT Libraries Government Documents Department
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Equilibrium dissociation pressures of lithium hydride and lithium deuteride. [450 to 750/sup 0/C]

Description: The equilibrium dissociation pressures of plateau composition lithium hydride and lithium deuteride have been measured from 450 to 750/sup 0/C. These data were used to derive the relationship of dissociation pressure with temperature over this range and to calculate several thermodynamic properties of these materials. Thermodynamic properties determined included the enthalpy, entropy, and free energy of formation; the enthalpy and entropy of fusion; and the melting points.
Date: December 1, 1977
Creator: Smith, H. M. & Webb, R. E.
Partner: UNT Libraries Government Documents Department
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Reactions of ions with atomic and molecular free radicals. Progress report, May 1, 1981-April 30, 1982. [Summaries of research activities at the University of Minnesota]

Description: Analysis and interpretation of the data on the reactions of H/sub 2//sup +/ with N, C, O and F were completed, along with some supplementary investigations of collision-induced dissociation of the exotic species NH/sub 3//sup 2 +/ and CS/sub 2//sup 3 +/. As the focus of this project shifts to other systems and phenomena, construction of a new crossed, pulsed molecular beam apparatus has been begun, and is now about 75% complete. The new instrument will permit state-resolved studies of energy tr… more
Date: November 1, 1981
Creator: Gentry, W.R.
Partner: UNT Libraries Government Documents Department
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Studies of atmospheric molecules by multiphoton spectroscopy

Description: Carbon dioxide presents a great challenge to spectroscopy because of its propensity toward dissociation in all of its excited states. Multiphoton ionization spectroscopy is usually not applicable to the study of dissociating molecules because the dissociation competes effectively with ionization, resulting in no signal. We reasoned, however, that with high enough laser fluence, ionization could compete with dissociation in the longer lived states, exposing them for study from the continuous spe… more
Date: October 1, 1991
Creator: Johnson, P.M.
Partner: UNT Libraries Government Documents Department
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Excitation of atoms and molecules in collisions with highly charged ions

Description: This report discusses research of multicharged nitrogen, oxygen and carbon monoxide molecular ions produced with collision with multicharged argon ions. Properties like ionization, dissociation, and excitation are investigated. (LSP)
Date: March 1, 1992
Creator: Watson, R.L.
Partner: UNT Libraries Government Documents Department
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Automotive storage of hydrogen using modified magnesium hydrides. Final report, March 1976-March 1978

Description: Metal hydrides can store more hydrogen per unit volume than normal high pressure or cryogenic techniques. Little energy is required to store the hydrogen in the hydride, and high stability at room temperature ensures low losses over long storage periods. Safety features of metal hydride storage are favorable. Because of its low weight and high hydrogen storage densities, modified magnesium hydride offers the greatest potential for automotive storage of hydrogen. Experimental and analytical work… more
Date: January 1, 1979
Creator: Rohy, D. A.; Nachman, J. F.; Hammer, A. N. & Duffy, T. E.
Partner: UNT Libraries Government Documents Department
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Experimental and computer modeling studies of isotopically selective two-step laser photodissociation of small molecules

Description: The approach to laser isotope separation taken in this study is based on isotopically selective, two-step, laser photodissociation of small molecules. A primary goal of this study is the measurement of fundamental molecular processes which control the two-step, photodissociative isotope enrichment process. This objective has led to experimental measurements of uv photodissociation cross sections for vibrationally excited states of several small molecules, including the first cross section repor… more
Date: March 25, 1992
Creator: Zittel, P.F.
Partner: UNT Libraries Government Documents Department
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Dissociative excitation as the source of neutral atoms in hydrogen discharges

Description: Electron impact dissociative excitation of H/sub 2/ molecules is identified as the origin of the narrow width and structure of Balmer lines observed in various low density hydrogen discharges. On the basis of this data and estimates of the rates of competing processes in plasmas, dissociative excitation, together with other molecular reactions, is proposed as the source of neutral atoms and protons in these discharges.
Date: January 1, 1980
Creator: McNeill, D.H.
Partner: UNT Libraries Government Documents Department
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Spectroscopy, reaction, and photodissociation in highly vibrationally excited molecules

Description: Highly vibrationally excited molecules often control the course of chemical reactions in the atmosphere, combustion, plasmas, and many other environments. The research described in this Progress Report uses laser excitation and interrogation techniques to study and control the dynamics of highly vibrationally excited molecules. In particular, they show that it is possible to unravel the details and influence the course of photodissociation and bimolecular reaction. The experiments use laser exc… more
Date: January 1, 1991
Partner: UNT Libraries Government Documents Department
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Multiphoton processes in isolated atoms and molecules

Description: The theory of coherent excitation of a multilevel quantum mechanical system is developed. Damping of the system is taken into account by the use of a density matrix formalism. General properties of the wave function and/or the density matrix are discussed. The physical implications for the behavior of the system are described, together with possible applications of the formalism, including the infrared multiphoton excitation of molecules, and optical pumping in alkali atoms. Experimental result… more
Date: November 1, 1979
Creator: Sudbo, A.S.
Partner: UNT Libraries Government Documents Department
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C/sub 3/ /sub 4/ /sub 5//sup -/ and NCO/sup +/ /sup -/ molecular ion structure determination by Coulomb explosion

Description: The purpose of these experiments is to acquire structural information about molecules through their Coulomb explosion in thin carbon foils. The data presented here relate to the structure of C/sub 3//sup -/, C/sub 4//sup -/, C/sub 5//sup -/, NCO/sup -/, and NCO/sup +/ molecular ions where the resulting multiple charged ions from the Coulomb explosion were detected in polycarbonate sheets. A preliminary analysis of the C/sub 3//sup -/ and NCO/sup -/ molecular structure data has been made and is … more
Date: February 1, 1980
Creator: Goldring, G; Eisen, Y; Filevich, A; Thieberger, P & Wegner, H E
Partner: UNT Libraries Government Documents Department
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Laser Drilling: Drilling with the Power of Light Phase 1: Feasibility Study

Description: A laser drilling research team was formed from members of academia, industry and national laboratory to explore the feasibility of using modern high-powered lasers to drill and complete oil and gas wells. The one-year Phase 1 study discussed in this report had the goals of quantifying the amount of pulsed infrared laser energy needed to spall and melt rock of varying lithologies and to investigate the possibility of accomplishing the same task in water under atmospheric conditions. Previous wor… more
Date: September 1, 2001
Creator: Gahan, Brian C.; Parker, Richard A.; Graves, Ramona; Batarseh, Samih; Reed, Claude B.; Xu, Zhiyue et al.
Partner: UNT Libraries Government Documents Department
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Petrophysical Characterization and Reservoir Simulator for Methane Gas Production from Gulf of Mexico Hydrates

Description: Gas hydrates are crystalline, ice-like compounds of gas and water molecules that are formed under certain thermodynamic conditions. Hydrate deposits occur naturally within ocean sediments just below the sea floor at temperatures and pressures existing below about 500 meters water depth. Gas hydrate is also stable in conjunction with the permafrost in the Arctic. Most marine gas hydrate is formed of microbially generated gas. It binds huge amounts of methane into the sediments. Estimates of the … more
Date: June 30, 2006
Creator: Mohanty, Kishore; Cook, Bill; Hakimuddin, Mustafa; Pitchumani, Ramanan; Ogunlana, Damiola; Burger, Jon et al.
Partner: UNT Libraries Government Documents Department
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TOUGH+Hydrate v1.0 User's Manual: A Code for the Simulation of System Behavior in Hydrate-Bearing Geologic Media

Description: TOUGH+HYDRATE v1.0 is a new code for the simulation of the behavior of hydrate-bearing geologic systems. By solving the coupled equations of mass and heat balance, TOUGH+HYDRATE can model the non-isothermal gas release, phase behavior and flow of fluids and heat under conditions typical of common natural CH{sub 4}-hydrate deposits (i.e., in the permafrost and in deep ocean sediments) in complex geological media at any scale (from laboratory to reservoir) at which Darcy's law is valid. TOUGH+HYD… more
Date: March 1, 2008
Creator: Moridis, George; Moridis, George J.; Kowalsky, Michael B. & Pruess, Karsten
Partner: UNT Libraries Government Documents Department
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