Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization

Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization

Date: May 2013
Creator: Figg, Travis M.
Description: There is a high demand for the development of processes for the conversion of ubiquitous molecules into industrially useful commodities. Transition metal catalysts are often utilized for the activation and functionalization of small organic molecules due to their diverse nature and proven utility with a myriad of chemical transformations. The functionalization of methane (CH4) and dinitrogen (N2) to methanol (CH3OH) and ammonia (NH3) respectively is of particular interest; however, both methane and dinitrogen are essentially inert due to the inherit strength of their bonds. In this dissertation a series of computational studies is performed to better understand the fundamental chemistry behind the functionalization of methane and the activation of dinitrogen in a homogeneous environment. A catalytic cycle is proposed for the oxy-functionalization of methane to methanol. The cycle consists of two key steps: (1) C-H activation across a metal-alkoxide bond (M-OR), and (2) regeneration of the M-OR species through an oxy-insertion step utilizing external oxidants. The C-H activation step has been extensively studied; however, the latter step is not as well understood with limited examples. For this work, we focus on the oxy-insertion step starting with a class of compounds known to do C-H activation (i.e., Pt(II) systems). Computational studies ...
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Water-soluble Phosphors for Hypoxia Detection in Chemical and Biological Media

Water-soluble Phosphors for Hypoxia Detection in Chemical and Biological Media

Access: Use of this item is restricted to the UNT Community.
Date: December 2012
Creator: Satumtira, Nisa Tara
Description: Water-soluble Pt(II) phosphors exist predominantly for photophysical studies. However, fewer are known to be candidates for cisplatin derivatives. If such a molecule could exist, it would be efficient at not only destroying the cancerous cells which harm the body, but the destruction would also be traceable within the human body as it occurred. Herein, research accomplished in chemistry describes the photophysical properties of a water-soluble phosphor. Spectroscopically, this phosphor is unique in that it possesses a strong green emission at room temperature in aqueous media. Its emission is also sensitive to the gaseous environment. These properties have been expanded to both analytical and biological applications. Studies showing the potential use of the phosphor as a heavy metal remover from aqueous solutions have been accomplished. The removal of toxic heavy metals was indicated by the loss of emission as well as the appearance of a precipitate. The gaseous sensitivity was elicited to be used as a potential cancerous cell biomarker. In vivo studies were accomplished in a wide variety of species, including bacteria (E. coli), worms (C. elegans), small crustaceans (Artemia), and fish (D. rerio and S. ocellatus). The phosphor in question is detectable in all of the above. This fundamental ...
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A Comparative Study of Errors in Chemistry and English Found in Examination Papers of Freshman Chemistry

A Comparative Study of Errors in Chemistry and English Found in Examination Papers of Freshman Chemistry

Date: August 1938
Creator: Phillips, Annie
Description: This study attempts to discover what types of errors are commonly made by students in freshman chemistry classes. It considers the errors resulting from the students' lack of knowledge of the subject taught, and errors attributed to their failure to use correct English in their expression of ideas.
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Comparison of Homework Systems (Four Web-Based) used in First-Semester General Chemistry

Comparison of Homework Systems (Four Web-Based) used in First-Semester General Chemistry

Date: May 2009
Creator: Belland, Joshua
Description: Web-based homework systems are becoming more common in general chemistry as instructors face ever-increasing enrollment. Yet providing meaningful feedback on assignments remains of the utmost importance. Chemistry instructors consider completion of homework integral to students' success in chemistry, yet only a few studies have compared the use of Web-based systems to the traditional paper-and-pencil homework within general chemistry. This study compares the traditional homework system to four different Web-based systems. Data from eight, semester classes consisting of a diagnostic pre-test, final semester grades, and the number of successful and unsuccessful students are analyzed. Statistically significant results suggest a chemistry instructor should carefully consider options when selecting a homework system.
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Micro electromechanical systems (MEMS) for mechanical engineers

Micro electromechanical systems (MEMS) for mechanical engineers

Date: November 18, 1996
Creator: Lee, A. P., LLNL
Description: The ongoing advances in Microelectromechanical Systems (MEMS) are providing man-kind the freedom to travel to dimensional spaces never before conceivable. Advances include new fabrication processes, new materials, tailored modeling tools, new fabrication machines, systems integration, and more detailed studies of physics and surface chemistry as applied to the micro scale. In the ten years since its inauguration, MEMS technology is penetrating industries of automobile, healthcare, biotechnology, sports/entertainment, measurement systems, data storage, photonics/optics, computer, aerospace, precision instruments/robotics, and environment monitoring. It is projected that by the turn of the century, MEMS will impact every individual in the industrial world, totaling sales up to $14 billion (source: System Planning Corp.). MEMS programs in major universities have spawned up all over the United States, preparing the brain-power and expertise for the next wave of MEMS breakthroughs. It should be pointed out that although MEMS has been initiated by electrical engineering researchers through the involvement of IC fabrication techniques, today it has evolved such that it requires a totally multi-disciplinary team to develop useful devices. Mechanical engineers are especially crucial to the success of MEMS development, since 90% of the physical realm involved is mechanical. Mechanical engineers are needed for the design of MEMS, ...
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Fundamental limits on NOx reduction by plasma

Fundamental limits on NOx reduction by plasma

Date: April 7, 1997
Creator: Penetrante, B. M., LLNL
Description: This paper discusses the gas-phase reaction mechanisms for removal of NO{sub x} in a plasma. The effect of oxygen content on the competition between the reduction and oxidation processes is discussed. The effect of the electron kinetic energy distribution on the radical production and subsequent chemistry is then discussed in order to predict the best performance that can be achieved for NO{sub x} reduction using the plasma alone. The fundamental limit on the minimum electrical energy consumption that will be required to implement NO{sub x} reduction in any type of plasma reactor is established.
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Removal of NOx from diesel generator exhaust by pulsed electron beams

Removal of NOx from diesel generator exhaust by pulsed electron beams

Date: July 3, 1997
Creator: Penetrante, B. M., LLNL
Description: The objective of this paper is to determine the effects of electron beam pulse parameters on the utilization of the reactive free radicals for removal of NO{sub x} from diesel generator exhaust. A dose per pulse less than 1 kGy has been determined to be optimum for effective radical utilization. During each post-pulse period, the radicals are utilized in the removal of NO{sub x} in a timescale of around 100 microseconds; thus, with pulse frequencies of around 10 kHz or less, the radical concentrations remain sufficiently low to prevent any significant competition between radical-pollutant and radical-radical reactions. It is shown that a pulsed electron beam reactor, operating with a dose per pulse of less than 1 kGy/pulse and pulse repetition rate of less than 10 kHz, will have the same plasma chemistry efficiency (parts per million of removed NO{sub x} per kGy of electron beam dose) as an electron beam reactor operating with a low dose rate of 50 kGy/s in continuous mode. Ozone accumulation is a limiting factor under high pulse frequency conditions. The total dose requirement determines the optimum combination of dose per pulse and pulse frequency for both radical utilization and prevention of ozone buildup.
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Changes in permeability and fluid chemistry of the Topopah Spring Member of the Paintbrush tuff (Nevada Test Site) when held in a temperature gradient: summary of results

Changes in permeability and fluid chemistry of the Topopah Spring Member of the Paintbrush tuff (Nevada Test Site) when held in a temperature gradient: summary of results

Date: June 1, 1984
Creator: Moore, D.E.; Morrow, C.A. & Byerlee, J.D.
Description: The permeability and groundwater chemistry results for the Topopah Spring Member are reported and compared with the results from the previous work on Bullfrog. Permeability measurements made on samples of the Topopah Spring Member of the Paintbrush Tuff at room-temperature and in a temperature gradient show that the initially high (3-65 {mu}da) permeabilities are little affected by heating to at least 150{sup 0}C. These permeability relationships are favvorable for the disposal of nuclear waste in this stuff in an unsaturated zone at the Nevada Test Site. The fluids discharged from the samples of tuff during the experiments are dilute, nearly neutral solutions that differ only slightly from the starting groundwater composition. 8 references, 10 figures, 5 tables.
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REMEDIATION OF LEON WATER FLOOD, BUTLER COUNTY, KANSAS

REMEDIATION OF LEON WATER FLOOD, BUTLER COUNTY, KANSAS

Date: November 26, 2001
Creator: Korphage, M.L.; Kindscher, Kelly & Langhus, Bruce G.
Description: The Leon Water Flood site has undergone one season of soil amendments and growth of specialized plants meant to colonize and accelerate the remediation of the salt-impacted site. The researchers characterized the impacted soil as to chemistry, added soil amendments, and planted several species of seedlings, and seeded the scarred areas. After the first growing season, the surface soil was again characterized and groundcover was also characterized. While plant growth was quite meager across the area, soil chemistry did improve over most of the two scars.
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AISI/DOE Technology Roadmap Program: Cold Work Embrittlement of Interstitial Free Steel

AISI/DOE Technology Roadmap Program: Cold Work Embrittlement of Interstitial Free Steel

Date: October 31, 2002
Creator: Bowker, John T & Martin, Pierre
Description: This work addresses the issues of measurement of secondary cold work embrittlement (SCWE) of an IF steel in deep-drawn parts using laboratory tests, and its correlation with real part fracture. It aimed at evaluating the influence of the steel chemistry and processing condition, microstructure, and test conditions, on SCWE as well as the effect of SCWE on fatigue properties. Size 6-in. cups produced with various draw ratios or trimmed at different heights were tested to determine the ductile-to-brittle-transition temperature (DBTT) as a function of strain. The 2-in. cup/expansion test, bend test and fracture of notched specimens were also used to generate information complementary to that provided by the 6-inch cup/expansion test. The relationship between laboratory tests and fracture in real parts was established by testing large-scale parts. The fatigue behavior was investigated in the as-rolled and deep drawn (high stain) conditions, using prestrained specimens taken from the wall of a formed part.
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DNAPL Surface Chemistry: Its Impact on DNAPL Distribution in the Vadose Zone and its Manipulation to Enhance Remediation

DNAPL Surface Chemistry: Its Impact on DNAPL Distribution in the Vadose Zone and its Manipulation to Enhance Remediation

Date: June 16, 2003
Creator: Power, Suan; Grimberg, Stefan & Denham, Miles
Description: The remediation of DNAPLs in subsurface environments is often limited by the heterogeneous distribution of the organic fluid. The fraction of DNAPL that is in the high conductivity regions of the subsurface can often be recovered relatively easily, although DNAPL in lower conductivity regions is much more difficult to extract, either through direct pumping or remediation measures based on interface mass transfer. The distribution of DNAPL within the vadose zone is affected by a complex interplay of heterogeneities in the porous matrix and the interfacial properties defining the interactions among all fluid and solid phases. Decreasing the interfacial tension between a DNAPL and water in the vadose zone could change the spreading of the DNAPL, thereby increase the surface area for mass transfer and the effectiveness of soil vapor extraction remediation.
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CONTROL OF POLLUTANT EMISSIONS IN NATURAL GAS DIFFUSION FLAMES BY USING CASCADE BURNERS

CONTROL OF POLLUTANT EMISSIONS IN NATURAL GAS DIFFUSION FLAMES BY USING CASCADE BURNERS

Date: December 30, 2001
Creator: Qubbaj, Dr. Ala
Description: The goal of this exploratory research project is to control the pollutant emissions of diffusion flames by modifying the air infusion rate into the flame. The modification was achieved by installing a cascade of venturis around the burning gas jet. The basic idea behind this technique is controlling the stoichiometry of the flame through changing the flow dynamics and rates of mixing in the combustion zone with a set of venturis surrounding the flame. A natural gas jet diffusion flame at burner-exit Reynolds number of 5100 was examined with a set of venturis of specific sizes and spacing arrangement. The thermal and composition fields of the baseline and venturi-cascaded flames were numerically simulated using CFD-ACE+, an advanced computational environment software package. The instantaneous chemistry model was used as the reaction model. The concentration of NO was determined through CFD-POST, a post processing utility program for CFD-ACE+. The numerical results showed that, in the near-burner, midflame and far-burner regions, the venturi-cascaded flame had lower temperature by an average of 13%, 19% and 17%, respectively, and lower CO{sub 2} concentration by 35%, 37% and 32%, respectively, than the baseline flame. An opposite trend was noticed for O{sub 2} concentration; the cascaded flame ...
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FULL-SCALE TESTING OF ENHANCED MERCURY CONTROL TECHNOLOGIES FOR WET FGD SYSTEMS

FULL-SCALE TESTING OF ENHANCED MERCURY CONTROL TECHNOLOGIES FOR WET FGD SYSTEMS

Date: May 7, 2003
Creator: McDonald, D.K.; Amrhein, G.T.; Kudlac, G.A. & Yurchison, D. Madden
Description: Wet flue gas desulfurization (wet FGD) systems are currently installed on about 25% of the coal-fired utility generating capacity in the U.S., representing about 15% of the number of coal-fired units. Depending on the effect of operating parameters such as mercury content of the coal, form of mercury (elemental or oxidized) in the flue gas, scrubber spray tower configuration, liquid-to-gas ratio, and slurry chemistry, FGD systems can provide cost-effective, near-term mercury emissions control options with a proven history of commercial operation. For boilers already equipped with FGD systems, the incremental cost of any vapor phase mercury removal achieved is minimal. To be widely accepted and implemented, technical approaches that improve mercury removal performance for wet FGD systems should also have low incremental costs and have little or no impact on operation and SO{sub 2} removal performance. The ultimate goal of the Full-scale Testing of Enhanced Mercury Control for Wet FGD Systems Program was to commercialize methods for the control of mercury in coal-fired electric utility systems equipped with wet flue gas desulfurization (wet FGD). The program was funded by the U.S. Department of Energy's National Energy Technology Laboratory, the Ohio Coal Development Office within the Ohio Department of Development, and ...
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Direct Production of Silicones From Sand

Direct Production of Silicones From Sand

Date: September 30, 2001
Creator: Lewis, Larry N. & Lemmon, F.J. Schattenmann: J.P.
Description: Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.
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Final Report: Theoretical Studies on Radiation-Induced Transformations in Nucleic Acid Bases, May 1, 1993 - April 30, 1996

Final Report: Theoretical Studies on Radiation-Induced Transformations in Nucleic Acid Bases, May 1, 1993 - April 30, 1996

Date: April 30, 1996
Creator: Adamowicz, Ludwik
Description: In the proposal we identified several elemental molecular properties related to the effects observed in genetic material exposed to ionizing irradiation, and we studied them by means of the ab-initio quantum chemistry. The chemistry of irradiation is complex and biological consequences are significant. This includes cell death, mutations, carcinogenic transformations, etc. In the proposal we theoretically modeled several elemental processes related to the radiolysis of components of the nucleic acids, i.e., the pyrimidine nucleobases cytosine, uracine and thymine. Based on the state-of-the-art ab-initio calculations, we obtained information on the structural and spectroscopic properties of transition intermediate reactants.
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Gamma scale chemistry progress report

Gamma scale chemistry progress report

Date: June 1, 1948
Creator: Economides, M.; Estabrook, E. & Joy, E.F.
Description: This report considers the work done during the year ending June 30, 1948, present work being done and future plans on the determination of formulas, methods of preparation, and properties of as many compounds of postum as possible. An experimental approach to such a research problem on the element postum requires that procedures which may be used deal with ultramicro quantities of material. Such procedures on an ultramicro or gamma scale require special techniques by personnel trained in manipulating these small quantities of radioactive material. Equipment which may be used varies with the experiment considered. Often new apparatus must be developed or equipment previously developed and used in some other experiment must be modified. This generalized research problem is subdivided in the {open_quotes}Research Problems Outline{close_quotes}. The presentation of a survey of these research problems with reference to the outline for the year ending June 30, 1948 is a critical review of the work done by the Gamma Scale Chemistry Group as well as a consideration of future plans. The course which these future plans may follow will depend upon information which may be obtained when carrying out planned experiments.
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DOE pollution prevention in the 21st century

DOE pollution prevention in the 21st century

Date: October 1, 1996
Creator: unknown
Description: This document presents abstracts of the topics covered in the DOE Pollution Prevention in the 21st Century conference held July 9-11, 1996. These topics include: model facilities; Federal/NEPA/stake- holders; microchemistry; solvents and reduction; education and outreach; return on investments; energy management; decontamination and decommissioning; planning and regulations; environmental restoration; recycling; affirmative procurement in the executive branch; construction and demolition; materials exchange; and ISO 2000.
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Technical documentation of HGSYSTEM/UF{sub 6} model

Technical documentation of HGSYSTEM/UF{sub 6} model

Date: January 1, 1996
Creator: Hanna, S.R.; Chang, J.C. & Zhang, J.X.
Description: MMES has been directed to upgrade the safety analyses for the gaseous diffusion plants at Paducah KY and Piketon OH. These will require assessment of consequences of accidental releases of UF{sub 6} to the atmosphere at these plants. The HGSYSTEM model has been chosen as the basis for evaluating UF{sub 6} releases; it includes dispersion algorithms for dense gases and treats the chemistry and thermodynamics of HF, a major product of the reaction of UF{sub 6} with water vapor in air. Objective of this project was to incorporate additional capability into HGSYSTEM: UF{sub 6} chemistry and thermodynamics, plume lift-off algorithms, and wet and dry deposition. The HGSYSTEM modules are discussed. The hybrid HGSYSTEM/UF{sub 6} model has been evaluated in three ways.
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Research in the chemical sciences. Summaries of FY 1995

Research in the chemical sciences. Summaries of FY 1995

Date: September 1, 1995
Creator: unknown
Description: This summary book is published annually to provide information on research supported by the Department of Energy`s Division of Chemical Sciences, which is one of four Divisions of the Office of Basic Energy Sciences in the Office of Energy Research. These summaries provide the scientific and technical public, as well as the legislative and executive branches of the Government, information, either generally or in some depth, about the Chemical Sciences program. Scientists interested in proposing research for support will find the publication useful for gauging the scope of the present basic research program and it`s relationship to their interests. Proposals that expand this scope may also be considered or directed to more appropriate offices. The primary goal of the research summarized here is to add significantly to the knowledge base in which existing and future efficient and safe energy technologies can evolve. As a result, scientific excellence is a major criterion applied in the selection of research supported by the Division of Chemical Sciences, but another important consideration is emphasis on science that is advancing in ways that will produce new information related to energy.
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Theoretical and experimental study of mixed solvent electrolytes. Final report

Theoretical and experimental study of mixed solvent electrolytes. Final report

Date: January 31, 1995
Creator: Cummings, P.T. & O'Connell, J.P.
Description: The goals of the research program evolved into six areas: Molecular simulation of phase equilibria in aqueous and mixed solvent electrolyte solutions. Molecular simulation of solvation and structure in supercritical aqueous systems. Extension of experimental database on mixed solvent electrolytes. Analysis of the thermodynamic properties of mixed solvent electrolyte solutions and mixed electrolyte solutions using fluctuation solution theory. Development of analytic expressions for thermodynamic properties of mixed solvent electrolyte solutions using analytically solved integral equation approximations. Fundamental modeling of mixed solvent electrolytes using numerically solved integral equation approximation theories.
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A generic approach to improved semi-solid forming of metals

A generic approach to improved semi-solid forming of metals

Date: June 5, 2002
Creator: Klier, E. M.
Description: Lack of technology for the production of large inexpensive feedstock, with uniform spherical primary phase throughout as required for semi-solid forming, has restricted realization of the full potential for the semi-solid forming process. Furthermore, narrow process windows and alloy chemistry restrictions increase process costs and limit performance attributes possible with existing semi-solid metal systems. Successful semi-solid forming trials utilizing Chesapeake Composites Corporation's DSC trademark Metals for feedstock indicate that this represents a generic approach to providing a permanent highly uniform, spherical solid phase, without electromagnetic or mechanical shearing. This approach also provides for further growth of semi-solid forming by providing for: low cost large diameter billet stock, reduced semi-solid forming costs, extension of semi-solid forming to new alloy systems, and semi-solid formed components with substantially enhanced physical and mechanical proper ties.
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Final report of research supported by DOE Grant No. DE-FG02-96ER14635: Photochemical studies of two component systems within the restricted spaces of zeolites.

Final report of research supported by DOE Grant No. DE-FG02-96ER14635: Photochemical studies of two component systems within the restricted spaces of zeolites.

Date: May 5, 2002
Creator: Ramamurthy, V.
Description: Most chemistry in nature occurs within a closed and confined space. In contrast to this time-evolved [m?] organic chemists have focused their interests in developing reaction methods in solution. The price for this is paid in terms of non-selectivity in product formation, expensive reagents, and enormous wastes. Eventually 'man-developed' solution methods to make molecules have to be replaced by more selective, more environmentally friendly, and less expensive strategies. One approach in this direction would be to use controlled environments. The project focused towards developing energy efficient methods to prepare energy rich molecules that were useful to the public. In this context synthetic zeolites, the counterpart of naturally occurring minerals, were explored as the reaction media.
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Plant training grant: DE-FG02-94ER20162. Final technical report

Plant training grant: DE-FG02-94ER20162. Final technical report

Date: February 1, 2003
Creator: Cashmore, Anthony R.
Description: The aim of this training grant was to educate students of Plant Science in the disciplines of Biochemistry and Chemistry, in addition to the more traditional courses in Plant Biology. Annual retreats were held which involved a day-long meeting and included lectures from Penn faculty as well as famous national and international scientists. Programs for two of these retreats are included. In addition to lecture courses, students performed research within the Departments of Biology, Chemistry, and Biochemistry and Biophysics; a publications list is given.
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Final Report: A Novel Tandem Homojunction Solar Cell, July 1, 1995 - June 30, 1999

Final Report: A Novel Tandem Homojunction Solar Cell, July 1, 1995 - June 30, 1999

Date: June 30, 1999
Creator: Parkinson, Bruce
Description: The eventual target material, ZnSnP{sub 2}, was difficult to grow with MBE because of the high phosphorus vapor pressure. We decided to begin by growing a similar material, ZnSnAs{sub 2}, that also has a band gap dependent on the growth temperature that is related to the metal sub lattice site disorder. We were successful at growing and characterizing this material with MBE. Single crystals of a variety of the chalcopyrite materials were also prepared and characterized. The single crystals were used for optical and electronic property comparisons with the MBE and MOMBE grown thin films. Films of ZnSnP{sub 2} were eventually grown using organophosphorus precursors in an MOMBE growth process. This was also described in a published paper. We also completed the most thorough solid state NMR characterization of 11-IV-V{sub 2} chalcopyrite semiconductors yet done. This paper will soon be submitted to ''Chemistry of Materials''. Although we did not succeed in preparing a photovoltaic device we did pioneer new growth methods for preparing epitaxial layers of these materials and were able to obtain acceptable electronic properties from the thin film materials. Five high quality publications and two PhD thesis were also a direct result of this research project.
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