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Hydrogen Oxidation-Driven Hot Electron Flow Detected by Catalytic Nanodiodes

Description: Hydrogen oxidation on platinum is shown to be a surface catalytic chemical reaction that generates a steady state flux of hot (>1 eV) conduction electrons. These hot electrons are detected as a steady-state chemicurrent across Pt/TiO{sub 2} Schottky diodes whose Pt surface is exposed to hydrogen and oxygen. Kinetic studies establish that the chemicurrent is proportional to turnover frequency for temperatures ranging from 298 to 373 K for P{sub H2} between 1 and 8 Torr and P{sub O2} at 760 To… more
Date: July 20, 2009
Creator: Hervier, Antoine; Renzas, J. Russell; Park, Jeong Y. & Somorjai, Gabor A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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2008 Photoions, Photoionization & Photodetachment Gordon Research Conference January 27-February 1, 2008

Description: This conference brings together scientists interested in a range of basic phenomena linked to the ejection and scattering of electrons from atoms, molecules, clusters, liquids and solids by absorption of light. Photoionization, a highly sensitive probe of both structure and dynamics, can range from perturbative single-photon processes to strong-field highly non-perturbative interactions. It is responsible for the formation and destruction of molecules in astrophysical and plasma environments an… more
Date: March 31, 2009
Creator: GRay, Klaus Muller-Dethefs Nancy Ryan
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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PROJECTED IMPACT OF SULFATE ATTACK ON THE LONG-TERM PERFORMANCE OF A CONCRETE REPOSITORY

Description: Saltstone is a cementitious waste form made by mixing salt solution originating from liquid waste storage tanks at the DOE Savannah River Site with a dry mix containing blast furnace slag, fly ash, and cement or lime. The wet mix is poured into a concrete repository for on-site disposal. Solidified Saltstone is a dense, alkaline, reducing, micro-porous, monolithic, cementitious matrix, containing a solution of salts within its pore structure. Sodium sulfate concentrations in the pore fluid are … more
Date: December 11, 2009
Creator: Flach, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Obtaining two attosecond pulses pulses for x-ray stimulated Raman spectroscopy

Description: Attosecond x-ray pulses are an indispensable tool for the study of electronic and structural changes in molecules undergoing chemical reactions. They have a wide bandwidth comparable to the energy bands of valence electronic states and, therefore, are well suited for making and probing multiple valence electronic excitations using core electron transitions. Here we propose a method of creating a sequence of two attosecond soft x-ray pulses in a free electron laser by optical manipulation of ele… more
Date: June 23, 2009
Creator: Zholents, Alexander & Penn, G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Overview of geologic storage of natural gas with an emphasis on assessing the feasibility of storing hydrogen.

Description: In many regions across the nation geologic formations are currently being used to store natural gas underground. Storage options are dictated by the regional geology and the operational need. The U.S. Department of Energy (DOE) has an interest in understanding theses various geologic storage options, the advantages and disadvantages, in the hopes of developing an underground facility for the storage of hydrogen as a low cost storage option, as part of the hydrogen delivery infrastructure. Curre… more
Date: September 1, 2009
Creator: Lord, Anna Snider
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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CHARACTERIZATION OF INDIVIDUAL CHEMICAL REACTIONS CONSUMING ACID DURING NUCLEAR WASTE PROCESSING AT THE SAVANNAH RIVER SITE - 136B

Description: Conversion of legacy radioactive high-level waste at the Savannah River Site into a stable glass waste form involves a chemical pretreatment process to prepare the waste for vitrification. Waste slurry is treated with nitric and formic acids to achieve certain goals. The total quantity of acid added to a batch of waste slurry is constrained by the catalytic activity of trace noble metal fission products in the waste that can convert formic acid into hydrogen gas at many hundreds of times the ra… more
Date: September 2, 2009
Creator: Koopman, D.; Pickenheim, B.; Lambert, D.; Newell, J. & Stone, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Next-Generation Photon Sources for Grand Challenges in Science and Energy

Description: The next generation of sustainable energy technologies will revolve around transformational new materials and chemical processes that convert energy efficiently among photons, electrons, and chemical bonds. New materials that tap sunlight, store electricity, or make fuel from splitting water or recycling carbon dioxide will need to be much smarter and more functional than today's commodity-based energy materials. To control and catalyze chemical reactions or to convert a solar photon to an elec… more
Date: May 1, 2009
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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ANALYSIS OF THE REACTIVITY OF RADPRO SOLUTION WITH COTTON RAGS

Description: Rags containing RadPro{reg_sign} solution will be generated during the decontamination of the Plutonium Finishing Plant (PFP). Under normal conditions, the rags will be neutralized with sodium carbonate prior to placing in the drums. The concern with RadPro solutions and cotton rags is that some of the RadPro solutions contain nitric acid. Under the right conditions, nitric acid and cotton rags exothermically react. The concern is, will RadPro solutions react with cotton rags exothermically? Th… more
Date: August 11, 2009
Creator: Marusich, R. M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Progresses in Ab Initio QM/MM Free Energy Simulations of Electrostatic Energies in Proteins: Accelerated QM/MM Studies of pKa, Redox Reactions and Solvation Free Energies

Description: Hybrid quantum mechanical / molecular mechanical (QM/MM) approaches have been used to provide a general scheme for chemical reactions in proteins. However, such approaches still present a major challenge to computational chemists, not only because of the need for very large computer time in order to evaluate the QM energy but also because of the need for propercomputational sampling. This review focuses on the sampling issue in QM/MM evaluations of electrostatic energies in proteins. We chose t… more
Date: March 1, 2009
Creator: Kamerlin, Shina C. L.; Haranczyk, Maciej & Warshel, Arieh
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A simplified model of TiH1.65/KClO4 pyrotechnic ignition.

Description: A simplified model was developed and is presented in this report for simulating thermal transport coupled with chemical reactions that lead to the pyrotechnic ignition of TiH1.65/KClO4 powder. The model takes into account Joule heating via a bridgewire, thermal contact resistance at the wire/powder interface, convective heat loss to the surroundings, and heat released from the TiH1.65- and KClO4-decomposition and TiO2-oxidation reactions. Chemical kinetic sub-models were put forth to describe t… more
Date: April 1, 2009
Creator: Chen, Ken Shuang
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes

Description: Tunneling electrons in a scanning tunneling microscope were used to excite specific vibrational quantum states of adsorbed water and hydroxyl molecules on a Ru(0 0 0 1) surface. The excited molecules relaxed by transfer of energy to lower energy modes, resulting in diffusion, dissociation, desorption, and surface-tip transfer processes. Diffusion of H{sub 2}O molecules could be induced by excitation of the O-H stretch vibration mode at 445 meV. Isolated molecules required excitation of one sing… more
Date: May 7, 2009
Creator: Mugarza, Aitor; Shimizu, Tomoko K.; Ogletree, D. Frank & Salmeron, Miquel
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Time-Resolved Molecular Frame Dynamics of Fixed-in-Space CS2 Molecules

Description: Random orientation of molecules within a sample leads to blurred observationsof chemical reactions studied from the laboratory perspective. Methodsdeveloped for the dynamic imaging of molecular structures and processesstruggle with this, as measurements are optimally made in the molecular frame.Here we uselaser alignment to transiently fix CS2 molecules in space longenough to elucidate, in the molecular reference frame, details of ultrafast electronic vibrationaldynamics during a photochemical … more
Date: April 2, 2009
Creator: Bisgaard, Christer; Clarkin, Owen; Wu, Guorong; Lee, Anthony; Gessner, Oliver; Hayden, Carl et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Photosynthesis

Description: Encyclopedia article entry in the Encyclopedia of Time: Science, Philosophy, Theology, and Culture by H. James Birx. This encyclopedia article discusses photosynthesis.
Date: 2009
Creator: O'Toole, Erin
Item Type: Refine your search to only Text
Partner: UNT Libraries
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Kinetic studies and computational modeling of atomic chlorine reactions in the gas phase.

Description: The gas phase reactions of atomic chlorine with hydrogen sulfide, ammonia, benzene, and ethylene are investigated using the laser flash photolysis / resonance fluorescence experimental technique. In addition, the kinetics of the reverse processes for the latter two elementary reactions are also studied experimentally. The absolute rate constants for these processes are measured over a wide range of conditions, and the results offer new accurate information about the reactivity and thermochemi… more
Date: August 2009
Creator: Alecu, Ionut M.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Quantifying Transient States in Materials with the Dynamic Transmission Electron Microscope

Description: The Dynamic Transmission Electron Microscope (DTEM) offers a means of capturing rapid evolution in a specimen through in-situ microscopy experiments by allowing 15 ns electron micrograph exposure times. The rapid exposure time is enabled by creating a burst of electrons at the emitter by ultraviolet pulsed laser illumination. This burst arrives a specified time after a second laser initiates the specimen reaction. The timing of the two Q-switched lasers is controlled by high-speed pulse generat… more
Date: September 21, 2009
Creator: Campbell, Geoffrey H.; LaGrange, Thomas; Kim, Judy S.; Reed, Bryan W. & Browning, Nigel D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Molecule-based approach for computing chemical-reaction rates in upper atmosphere hypersonic flows.

Description: This report summarizes the work completed during FY2009 for the LDRD project 09-1332 'Molecule-Based Approach for Computing Chemical-Reaction Rates in Upper-Atmosphere Hypersonic Flows'. The goal of this project was to apply a recently proposed approach for the Direct Simulation Monte Carlo (DSMC) method to calculate chemical-reaction rates for high-temperature atmospheric species. The new DSMC model reproduces measured equilibrium reaction rates without using any macroscopic reaction-rate info… more
Date: August 1, 2009
Creator: Gallis, Michail A.; Bond, Ryan Bomar & Torczynski, John R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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