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2011

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Articles 631 - 660 of 1068

Full-Text Articles in Chemistry

Dications Of Benzylidenefluorene And Diphenylmethylidene Fluorene: The Relationship Between Magnetic And Energetic Measures Of Antiaromaticity, Catherine Do, Julianne Hatfield, Shirali Patel, D Vasudevan, Cornelia Tirla, Nancy S. Mills Jan 2011

Dications Of Benzylidenefluorene And Diphenylmethylidene Fluorene: The Relationship Between Magnetic And Energetic Measures Of Antiaromaticity, Catherine Do, Julianne Hatfield, Shirali Patel, D Vasudevan, Cornelia Tirla, Nancy S. Mills

Chemistry Faculty Research

Oxidation of m- and p-substituted benzylidene fluorenes to antiaromatic dications was attempted by electrochemical and chemical means. Electrochemical oxidation to dications was successful for benzylidene fluorenes with p-methoxy, p-methyl, p-fluoro, and unsubstituted phenyl rings in the 3-position; attempts to oxidize the m-substituted derivatives via electrochemistry were unsuccessful. Chemical oxidation with SbF5/SO2ClF gave the dication of 9-[(4-methoxyphenyl)methylene]-9H-fluorene cleanly; oxidation of all other substituted benzylidene fluorenes resulted in mixtures of products. The excellent linear relationship between the chemical shifts calculated by the GIAO method and the experimental shifts for the p-methoxy-substituted benzylidene fluorene dication …

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Reduction Of Benzylidene Dibenzo[ A, D ]Cycloheptenes: Over-Reduction Of Antiaromatic Dianions To Aromatic Tetraanions, Blakely Tresca, Macdonald Higbee, Nancy S. Mills Jan 2011

Reduction Of Benzylidene Dibenzo[ A, D ]Cycloheptenes: Over-Reduction Of Antiaromatic Dianions To Aromatic Tetraanions, Blakely Tresca, Macdonald Higbee, Nancy S. Mills

Chemistry Faculty Research

The antiaromaticity of a series of dianions of p-substituted benzylidene dibenzo[a,d]cycloheptenes was examined through calculated measures of antiaromaticity. The nucleus-independent chemical shifts (NICS) and magnetic susceptibility exaltation both showed substantial antiaromatic character in the benzannulated tropylium anion. When the antiaromaticity was normalized for the area of the ring, these tropylium anions were shown to be among the most antiaromatic anions in the chemical literature. Attempts to make the dianion through reduction with lithium or potassium gave the tetraanion as the only species observable in the (1)H NMR spectrum. Quench of the reaction mixture with trimethylsilyl chloride or D(2)O confirmed the …

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Trends In Heavy-Duty Diesel Emissions And Analyses Of Colorado's Light-Duty Vehicle Inspection And Maintenance Program, Brent G. Schuchmann Jan 2011

Trends In Heavy-Duty Diesel Emissions And Analyses Of Colorado's Light-Duty Vehicle Inspection And Maintenance Program, Brent G. Schuchmann

Electronic Theses and Dissertations

Emission trends are reported and discussed resulting from the multi-year study of Heavy-Duty Diesel Vehicles (HDDV) at the Port of Los Angeles and at a weigh station in Peralta also in the L.A. basin. Remote sensing data were also collected from the Port of Houston and compared to the data from California. As part of San Pedro Bay Ports Clean Air Action Plan (CAAP) to fast track the turnover rate of cleaner trucks, many truck operators have been subject to modifying their trucks, or have purchased new trucks, with more advanced control technologies to reduce exhaust particulate matter (PM) and …

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A Bulk Water-Dependent Desolvation Energy Model For Analyzing The Effects Of Secondary Solutes On Biological Equilibria, Daryl K. Eggers Jan 2011

A Bulk Water-Dependent Desolvation Energy Model For Analyzing The Effects Of Secondary Solutes On Biological Equilibria, Daryl K. Eggers

Faculty Publications, Chemistry

A new phenomenological model for interpreting the effects of solutes on biological equilibria is presented. The model attributes changes in equilibria to differences in the desolvation energy of the reacting species that, in turn, reflect changes in the free energy of the bulk water upon addition of secondary solutes. The desolvation approach differs notably from that of other solute models by treating the free energy of bulk water as a variable and by not ascribing the observed shifts in reaction equilibria to accumulation or depletion of solutes next to the surfaces of the reacting species. On the contrary, the partitioning …

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The Tyranny Of The Vital Few: The Pareto Principle In Language Design, Victor L. Winter, James L. Perry, Harvey Siy, Satish Srinivasan, Ben Farkas, James Mccoy Jan 2011

The Tyranny Of The Vital Few: The Pareto Principle In Language Design, Victor L. Winter, James L. Perry, Harvey Siy, Satish Srinivasan, Ben Farkas, James Mccoy

Chemistry Faculty Publications

Modern high-level programming languages often contain constructs whose semantics are non-trivial. In practice how- ever, software developers generally restrict the use of such constructs to settings in which their semantics is simple (programmers use language constructs in ways they understand and can reason about). As a result, when developing tools for analyzing and manipulating software, a disproportionate amount of effort ends up being spent developing capabilities needed to analyze constructs in settings that are infrequently used. This paper takes the position that such distinctions between theory and practice are an important measure o f the analyzability of a language.

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Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez Jan 2011

Microfluidic Paper-Based Analytical Devices: From Pocket To Paper-Based Elisa, Andres W. Martinez

Chemistry and Biochemistry

Microfluidic paper-based analytical devices (microPADs) began as a simple idea with an ambitious goal. The idea was to make microfluidic devices out of paper instead of plastic or glass. The goal was to develop low-cost and portable paper-based diagnostic devices to improve healthcare in developing countries. Over the past 6 years, many developments have been made in the emerging field of paper-based microfluidic devices. Reviewing the development of these devices in the Whitesides group at Harvard University (Cambridge, MA, USA) can provide some insight into the future of the field and encourage scientists from a variety of backgrounds to contribute …

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Direct Immunosensor Design Based On The Electrochemical Reduction Of 4-((4-Nitrophenyl) Ethynyl) Benzenethiol Monolayers, Dwight A. Williams, Wraegen A. M. Williams, Melissa C. Rhoten, Charlene D. Crawley, Suzanne Ruder Jan 2011

Direct Immunosensor Design Based On The Electrochemical Reduction Of 4-((4-Nitrophenyl) Ethynyl) Benzenethiol Monolayers, Dwight A. Williams, Wraegen A. M. Williams, Melissa C. Rhoten, Charlene D. Crawley, Suzanne Ruder

Chemistry & Physics Faculty Publications

The synthesis and characterization of novel N-arylhydroxylamine-based molecular wires are described for use in the site-directed covalent immobilization of whole IgG antibodies onto gold electrode surfaces. The hydroxylamine, electrochemically generated in situ from reduction of the corresponding nitrobenzene, is stable under a wide range of solution conditions and reacts selectively with carbohydrate away from the antibody-binding site to allow the development of immunosensors with maximal activity. Cyclic voltammetric responses have shown a direct correlation between the structure and length of the molecular wire and its stability and concentration at the electrode surface.

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Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro Jan 2011

Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro

Faculty Publications, Chemistry

4-(2-Methylbutyl)aminodipicolinic acid (H2MEBADPA) has been synthesized and fully characterized in terms of aqueous phase protonation constants (pKa's) and photophysical measurements. The pKa's were determined by spectrophotometric titrations, utilizing a fully sealed titration system. Photophysical measurements consisted of room temperature fluorescence and frozen solution phosphorescence as well as quantum yield determinations at various pH, which showed that only fully deprotonated MEBADPA2– is appreciably emissive. The fluorescence of MEBADPA2– has been determined to be quenched by hydroxide and methoxide anions, most likely through base-catalyzed excited-state tautomerism or proton transfer. This quenching phenomenon has been quantitatively explored through steady-state and time-resolved fluorescence measurements. …

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Photosensitizer Drug Delivery Via An Optical Fiber, Matibur Zamadar, Goutam Ghosh, Adaic Kapillai Mahendran, Mihaela Minnis, Bonnie I. Kruft, Ashwini Ghogare, David Aebisher, Alexander Greer Jan 2011

Photosensitizer Drug Delivery Via An Optical Fiber, Matibur Zamadar, Goutam Ghosh, Adaic Kapillai Mahendran, Mihaela Minnis, Bonnie I. Kruft, Ashwini Ghogare, David Aebisher, Alexander Greer

Faculty Publications

: An optical fiber has been developed with a maneuverable miniprobe tip that sparges O2 gas and photodetaches pheophorbide (sensitizer) molecules. Singlet oxygen is produced at the probe tip surface which reacts with an alkene spacer group releasing sensitizer upon fragmentation of a dioxetane intermediate. Optimal sensitizer photorelease occurred when the probe tip was loaded with 60 nmol sensitizer, where crowding of the pheophorbide molecules and self-quenching were kept to a minimum. The fiber optic tip delivered pheophorbide molecules and singlet oxygen to discrete locations. The 60 nmol sensitizer was delivered into petrolatum; however, sensitizer release was less efficient in …

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Dft/Td-Dft Investigation Of Optical Absorption Spectra, Electron Affinities, And Ionization Potentials Of Mono-Nitrated Benzanthrones [Abstract], Kefa Karimu Onchoke Jan 2011

Dft/Td-Dft Investigation Of Optical Absorption Spectra, Electron Affinities, And Ionization Potentials Of Mono-Nitrated Benzanthrones [Abstract], Kefa Karimu Onchoke

Faculty Publications

No abstract provided.

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Incremental Binding Energies Of Gold (I) And Silver (I) Thiolate Clusters, Brian M. Barngrover, Christine M. Aikens Jan 2011

Incremental Binding Energies Of Gold (I) And Silver (I) Thiolate Clusters, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

Density functional theory is used to find incremental fragmentation energy, overall dissociation energy, and average monomer fragmentation energy of cyclic gold(I) thiolate clusters and anionic chain structures of gold(I) and silver(I) thiolate clusters as a measure of the relative stability of these systems. Two different functionals, BP86 and PBE, and two different basis sets, TZP and QZ4P, are employed. Anionic chains are examined with various residue groups including hydrogen, methyl, and phenyl. Hydrogen and methyl are shown to have approximately the same binding energy, which is higher than phenyl. Gold–thiolate clusters are bound more strongly than corresponding silver clusters. Lastly, …

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Electron And Hydride Addition To Gold (I) Thiolate Oligomers: Implications For Gold–Thiolate Nanoparticle Growth Mechanisms, Brian M. Barngrover, Christine M. Aikens Jan 2011

Electron And Hydride Addition To Gold (I) Thiolate Oligomers: Implications For Gold–Thiolate Nanoparticle Growth Mechanisms, Brian M. Barngrover, Christine M. Aikens

Faculty Publications

Electron and hydride addition to Au(I):SR oligomers is investigated using density functional theory. Cyclic and chain-like clusters are examined in this work. Dissociation to Au– ions and Aun(SR)n+1– chains is observed after 2–4 electrons are added to these systems. The free thiolate (SR–) is rarely produced in this work; dissociation of Au– is preferred over dissociation of SR–. Electron affinities calculated in gas phase, toluene, and water suggest that the electron addition process is unlikely, although it may be possible in polar solvents. In contrast, hydride addition to Au(I):SR …

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Better Biomolecule Thermodynamics From Kinetics, Kiran Girdhar, Gregory Scott, Yann R. Chemla, Martin Gruebele Jan 2011

Better Biomolecule Thermodynamics From Kinetics, Kiran Girdhar, Gregory Scott, Yann R. Chemla, Martin Gruebele

Chemistry and Biochemistry

Protein stability is measured by denaturation: When solvent conditions are changed (e.g., temperature, denaturant concentration, or pH) the protein population switches between thermodynamic states. The resulting denaturation curves have baselines. If the baselines are steep, nonlinear, or incomplete, it becomes difficult to characterize protein denaturation. Baselines arise because the chromophore probing denaturation is sensitive to solvent conditions, or because the thermodynamic states evolve structurally when solvent conditions are changed, or because the barriers are very low (downhill folding). Kinetics can largely eliminate such baselines: Relaxation of chromophores, or within thermodynamic states, is much faster than the transition over activation …

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Computational Models Of Chemical Systems Inspired By Braess’ Paradox, Dante Lepore, Carl Barratt, Pauline Schwartz Jan 2011

Computational Models Of Chemical Systems Inspired By Braess’ Paradox, Dante Lepore, Carl Barratt, Pauline Schwartz

Chemistry and Chemical Engineering Faculty Publications

Systems chemistry is a new discipline which investigates the interactions within a network of chemical reactions. We have studied several computational models of chemical systems inspired by mathematical paradoxes and have found that even simple systems may behave in a counterintuitive, non-linear manner depending upon various conditions. In the present study, we modeled a set of reactions inspired by one such paradox, Braess’ paradox, an interesting phenomenon whereby the introduction of additional capacity (e.g. pathways) in some simple network systems can lead to an unexpected reduction in the overall flow rate of “traffic” through the system. We devised several chemical …

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Characterization Of Oxidation Resistant Fe@M (M=Cr, Ni) Core@Shell Nanoparticles Prepared By A Modified Reverse Micelle Reaction, Sweta H. Naik, Kyler J. Carroll, Everett E. Carpenter Jan 2011

Characterization Of Oxidation Resistant Fe@M (M=Cr, Ni) Core@Shell Nanoparticles Prepared By A Modified Reverse Micelle Reaction, Sweta H. Naik, Kyler J. Carroll, Everett E. Carpenter

Chemistry Publications

Iron-based nanoparticles are the forerunners in the field of nanotechnology due to their high magnetizationsaturation and biocompability which affords them use in a variety of applications. However, iron-based nanoparticles, due to a high surface-to-volume ratio, suffer from oxidation and limit its practicality by lowering the magnetic moment significantly. To avoid this oxidation, the surfaces of the particles have to be passivated. One such way to accomplish this passivation is to synthesize core@shell nanoparticles that have a surface treatment of chromium or nickel. These core@shell nanoparticles have been synthesized using a reverse micelle technique. The Cr and Ni passivated ironnanoparticles were …

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Structure And Hydration Of The C4h4 •+ Ion Formed By Electron Impact Ionization Of Acetylene Clusters, Paul O. Momoh, Ahmed Hamid, Samuel A. Abrash, M. Samy El-Shall Jan 2011

Structure And Hydration Of The C4h4 •+ Ion Formed By Electron Impact Ionization Of Acetylene Clusters, Paul O. Momoh, Ahmed Hamid, Samuel A. Abrash, M. Samy El-Shall

Chemistry Publications

Here we report ion mobility experiments and theoretical studies aimed at elucidating the identity of the acetylene dimer cation and its hydrated structures. The mobility measurement indicates the presence of more than one isomer for the C4H4 •+ ion in the cluster beam. The measured average collision cross section of the C4H4 •+ isomers in helium (38.9 ± 1 Å2) is consistent with the calculated cross sections of the four most stable covalent structures calculated for the C4H4 •+ ion [methylenecyclopropene (39.9 Å2), 1,2,3-butatriene (41.1 Å2), cyclobutadiene (38.6 Å2), and vinyl acetylene …

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Bottom-Up Synthesis Of Gold Octahedra With Tailorable Hollow Features, Mark R. Langille, Michelle L. Personick, Jian Zhang, Chad A. Mirkin Jan 2011

Bottom-Up Synthesis Of Gold Octahedra With Tailorable Hollow Features, Mark R. Langille, Michelle L. Personick, Jian Zhang, Chad A. Mirkin

Department of Chemistry: Faculty Publications

Gold octahedra with hollow features have been synthesized in high yield via the controlled overgrowth of preformed concave cube seeds. This Ag+-assisted, seed-mediated synthesis allows for the average edge length of the octahedra and the size of the hollow features to be independently controlled. We propose that a high concentration of Ag+ stabilizes the {111} facets of the octahedra through underpotential deposition while the rate of Au+ reduction controls the dimensions of the hollow features. This synthesis represents a highly controllable bottom-up approach for the preparation of hollow gold nanostructures.

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Chemical Characterization Of Lake Gregory, Eric Steven Torres Jan 2011

Chemical Characterization Of Lake Gregory, Eric Steven Torres

Theses Digitization Project

The purpose of this study is to characterize the water chemistry of Lake Gregory in Crestline, California. The collection of water samples occurred a short time after the end of the summer recreational season in the late fall. Several chemical parameters were measured in an effort to determine the overall water quality during this time.

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Osmotic-Controlled Release Oral Delivery System (Oros) - The Application Of Oros Medication Delivery Technology: Present And Future, Adam J. Hood Jan 2011

Osmotic-Controlled Release Oral Delivery System (Oros) - The Application Of Oros Medication Delivery Technology: Present And Future, Adam J. Hood

Natural Sciences Student Research Presentations

No abstract provided.

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Carbon Nanotubes For Radiation Therapy, Pratyush Kolli Jan 2011

Carbon Nanotubes For Radiation Therapy, Pratyush Kolli

Natural Sciences Student Research Presentations

No abstract provided.

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Blast Furnace And Iron Production, Xin Ma Jan 2011

Blast Furnace And Iron Production, Xin Ma

Natural Sciences Student Research Presentations

No abstract provided.

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Self-Healing Polymers, Laura Ward Jan 2011

Self-Healing Polymers, Laura Ward

Natural Sciences Student Research Presentations

No abstract provided.

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The Fire Inventory From Ncar (Finn): A High Resolution Global Model To Estimate The Emissions From Open Burning, C. Wiedinmyer, S. K. Akagi, Robert J. Yokelson, L. K. Emmons, J. A. Al-Saadi, J. J. Orlando, A. J. Soja Jan 2011

The Fire Inventory From Ncar (Finn): A High Resolution Global Model To Estimate The Emissions From Open Burning, C. Wiedinmyer, S. K. Akagi, Robert J. Yokelson, L. K. Emmons, J. A. Al-Saadi, J. J. Orlando, A. J. Soja

Chemistry and Biochemistry Faculty Publications

The Fire INventory from NCAR version 1.0 (FINNv1) provides daily, 1 km resolution, global estimates of the trace gas and particle emissions from open burning of biomass, which includes wildfire, agricultural fires, and prescribed burning and does not include biofuel use and trash burning. Emission factors used in the calculations have been updated with recent data, particularly for the non-methane organic compounds (NMOC). The resulting global annual NMOC emission estimates are as much as a factor of 5 greater than some prior estimates. Chemical speciation profiles, necessary to allocate the total NMOC emission estimates to lumped species for use by …

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Emission Factors For Open And Domestic Biomass Burning For Use In Atmospheric Models, S. K. Akagi, Robert J. Yokelson, C. Wiedinmyer, M. Alvarado, J. S. Reid, T. Karl, J. D. Crounse, P. O. Wennberg Jan 2011

Emission Factors For Open And Domestic Biomass Burning For Use In Atmospheric Models, S. K. Akagi, Robert J. Yokelson, C. Wiedinmyer, M. Alvarado, J. S. Reid, T. Karl, J. D. Crounse, P. O. Wennberg

Chemistry and Biochemistry Faculty Publications

Biomass burning (BB) is the second largest source of trace gases and the largest source of primary fine carbonaceous particles in the global troposphere. Many recent BB studies have provided new emission factor (EF) measurements. This is especially true for non-methane organic compounds (NMOC), which influence secondary organic aerosol (SOA) and ozone formation. New EF should improve regional to global BB emissions estimates and therefore, the input for atmospheric models. In this work we present an up-to-date, comprehensive tabulation of EF for known pyrogenic species based on measurements made in smoke that has cooled to ambient temperature, but not yet …

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Airborne And Ground-Based Measurements Of The Trace Gases And Particles Emitted By Prescribed Fires In The United States, I. R. Burling, Robert J. Yokelson, S. K. Akagi, S. P. Urbanski, C. E. Wold, David W. T. Griffith, T. J. Johnson, J. Reardon, D. R. Weise Jan 2011

Airborne And Ground-Based Measurements Of The Trace Gases And Particles Emitted By Prescribed Fires In The United States, I. R. Burling, Robert J. Yokelson, S. K. Akagi, S. P. Urbanski, C. E. Wold, David W. T. Griffith, T. J. Johnson, J. Reardon, D. R. Weise

Chemistry and Biochemistry Faculty Publications

We have measured emission factors for 19 trace gas species and particulate matter (PM2.5) from 14 prescribed fires in chaparral and oak savanna in the southwestern US, as well as conifer forest understory in the southeastern US and Sierra Nevada mountains of California. These are likely the most extensive emission factor field measurements for temperate biomass burning to date and the only published emission factors for temperate oak savanna fuels. This study helps to close the gap in emissions data available for temperate zone fires relative to tropical biomass burning. We present the first field measurements of the biomass burning …

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Trace Gas And Particle Emissions From Open Biomass Burning In Mexico, Robert J. Yokelson, I. R. Burling, S. P. Urbanski, E. Atlas, K. Adachi, P. R. Buseck, C. Wiedinmyer, S. K. Akagi, D. W. Toohey, C. E. Wold Jan 2011

Trace Gas And Particle Emissions From Open Biomass Burning In Mexico, Robert J. Yokelson, I. R. Burling, S. P. Urbanski, E. Atlas, K. Adachi, P. R. Buseck, C. Wiedinmyer, S. K. Akagi, D. W. Toohey, C. E. Wold

Chemistry and Biochemistry Faculty Publications

We report airborne measurements of emission factors (EF) for trace gases and PM(2.5) made in southern Mexico in March of 2006 on 6 crop residue fires, 3 tropical dry forest fires, 8 savanna fires, 1 garbage fire, and 7 mountain pine-oak forest fires. The savanna fire EF were measured early in the local dry season and when compared to EF measured late in the African dry season they were at least 1.7 times larger for NO(x), NH(3), H(2), and most non-methane organic compounds. Our measurements suggest that urban deposition and high windspeed may also be associated with significantly elevated NOx …

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Boreal Forest Fire Emissions In Fresh Canadian Smoke Plumes: C-1-C-10 Volatile Organic Compounds (Vocs), Co2, Co, No2, No, Hcn And Ch3cn, Isobel J. Simpson, S. K. Akagi, B. Barletta, N. J. Blake, Y. Choi, G. S. Diskin, A. Fried, H. E. Fuelberg, S. Meinardi, F. S. Rowland, S. A. Vay, A. J. Weinheimer, P. O. Wennberg, P. Wiebring, A. Wisthaler, M. Yang, Robert J. Yokelson, Donald R. Blake Jan 2011

Boreal Forest Fire Emissions In Fresh Canadian Smoke Plumes: C-1-C-10 Volatile Organic Compounds (Vocs), Co2, Co, No2, No, Hcn And Ch3cn, Isobel J. Simpson, S. K. Akagi, B. Barletta, N. J. Blake, Y. Choi, G. S. Diskin, A. Fried, H. E. Fuelberg, S. Meinardi, F. S. Rowland, S. A. Vay, A. J. Weinheimer, P. O. Wennberg, P. Wiebring, A. Wisthaler, M. Yang, Robert J. Yokelson, Donald R. Blake

Chemistry and Biochemistry Faculty Publications

Boreal regions comprise about 17% of the global land area, and they both affect and are influenced by climate change. To better understand boreal forest fire emissions and plume evolution, 947 whole air samples were collected aboard the NASA DC-8 research aircraft in summer 2008 as part of the ARCTAS-B field mission, and analyzed for 79 non-methane volatile organic compounds (NMVOCs) using gas chromatography. Together with simultaneous measurements of CO2, CO, CH4, CH2O, NO2, NO, HCN and CH3CN, these measurements represent the most comprehensive assessment of trace gas emissions from boreal forest fires to date. Based on 105 air samples …

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A Topological Approach To Molecular Chirality, Erica Flapan Jan 2011

A Topological Approach To Molecular Chirality, Erica Flapan

Pomona Faculty Publications and Research

Topology is the study of deformations of geometric figures. Chemistry is the study of molecular structures. At first glance these fields seem to have nothing in common. But let’s take a closer look to see how these fields come together in the study of molecular symmetries.

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Density Functional Theory Study Of Molecules And Crystals Containing D And F Metals, Shruba Gangopadhyay Jan 2011

Density Functional Theory Study Of Molecules And Crystals Containing D And F Metals, Shruba Gangopadhyay

Electronic Theses and Dissertations

Density Functional Theory (DFT) method is applied to study the crystal structure of transition metal and lanthanide oxides, as well as molecular magnetic complexes. DFT is a widely popular computational approach because it recasts a many-body problem of interacting electrons into an equivalent problem of non-interacting electrons, greatly reducing computational cost. We show that for certain structural properties like phase stability, lattice parameter and oxygen migration energetics pure DFT can give good agreement with experiments. But moving to more sensitive properties like spin state energetic certain modifications of standard DFT are needed. First we investigated mixed ionic-electronic conducting perovskite type …

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Self-Assembly Of Squaraine Dyes, Maher A. Qaddoura Jan 2011

Self-Assembly Of Squaraine Dyes, Maher A. Qaddoura

Electronic Theses and Dissertations

Squaraine dyes have been a subject of extensive investigations lately due to their wide applications in important technological fields such as bioimaging probes, bioconjucation, second generation photosensitizers for photodynamic therapy, second harmonic generating organic dyes, two-photon absorbing materials with large cross section values, and, finally, photoconducting materials in photovoltaic cells. While a large number of patents and papers has been produced regarding their applications limited work has been done concerning their thermotropic behavior, including their liquid crystalline properties, or correlation of the crystalline structure to both the solid state aggregation and their photophysical properties. In the first chapter of this …

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