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Physical Chemistry

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2014

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Articles 1 - 30 of 30

Full-Text Articles in Physical Sciences and Mathematics

Comparison Of Upper Tropospheric Carbon Monoxide From Mopitt, Ace-Fts, And Hippo-Qcls, Sara Martínez-Alonzo, Merritt N. Deeter, Helen M. Worden, John C. Gille, Louisa K. Emmons, Laura L. Pan, Mijeong Park, Gloria L. Manney, Peter F. Bernath, Chris D. Boone Dec 2014

Comparison Of Upper Tropospheric Carbon Monoxide From Mopitt, Ace-Fts, And Hippo-Qcls, Sara Martínez-Alonzo, Merritt N. Deeter, Helen M. Worden, John C. Gille, Louisa K. Emmons, Laura L. Pan, Mijeong Park, Gloria L. Manney, Peter F. Bernath, Chris D. Boone

Chemistry & Biochemistry Faculty Publications

Products from the Measurements Of Pollution In The Troposphere (MOPITT) instrument are regularly validated using in situ airborne measurements. However, few of these measurements reach into the upper troposphere, thus hindering MOPITT validation in that region. Here we evaluate upper tropospheric (~500 hPa to the tropopause) MOPITT CO profiles by comparing them to satellite Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) retrievals and to measurements from the High-performance Instrumented Airborne Platform for Environmental Research Pole to Pole Observations (HIPPO) Quantum Cascade Laser Spectrometer (QCLS). Direct comparison of colocated v5 MOPITT thermal infrared-only retrievals, v3.0 ACE-FTS retrievals, and HIPPO-QCLS measurements shows …

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Development And Application Of Combined Quantum Mechanical And Molecular Mechanical Methods, Rui Lai Dec 2014

Development And Application Of Combined Quantum Mechanical And Molecular Mechanical Methods, Rui Lai

Department of Chemistry: Dissertations, Theses, and Student Research

Compromising of computational cost and accuracy, combined quantum mechanical and molecular mechanical (QM/MM) methods are practical methods for studying large molecular systems. The use of induced dipole polarizable force fields can significantly improve the accuracy of MM and QM/MM methods. However, induced dipole models tend to overestimate the polarization energy at short interaction distances. Damping functions can be applied to reduce the over polarization. MM-MM damping schemes have been developed to correct the overestimated polarization between MM atoms; QM-MM damping scheme has not been developed. In this thesis, a QM-MM damping scheme is developed for the damping of the MM …

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Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman Nov 2014

Catechol Oxidation By Ozone And Hydroxyl Radicals At The Air-Water Interface, Elizabeth A. Pillar, Robert C. Camm, Marcelo I. Guzman

Chemistry Faculty Publications

Anthropogenic emissions of aromatic hydrocarbons promptly react with hydroxyl radicals undergoing oxidation to form phenols and polyphenols (e.g., catechol) typically identified in the complex mixture of humic-like substances (HULIS). Because further processing of polyphenols in secondary organic aerosols (SOA) can continue mediated by a mechanism of ozonolysis at interfaces, a better understanding about how these reactions proceed at the air–water interface is needed. This work shows how catechol, a molecular probe of the oxygenated aromatic hydrocarbons present in SOA, can contribute interfacial reactive species that enhance the production of HULIS under atmospheric conditions. Reactive semiquinone radicals are quickly produced upon …

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Line Lists For The A2Π-X 2Σ+ (Red) And B2Σ+-X 2Σ+ (Violet) Systems Of Cn, 13c14n, And 12c15n, And Application To Astronomicalspectra, Christopher Sneden, Sara Lucatello, Ram S. Ram, James S. A. Brooke, Peter Bernath Oct 2014

Line Lists For The A2Π-X 2Σ+ (Red) And B2Σ+-X 2Σ+ (Violet) Systems Of Cn, 13c14n, And 12c15n, And Application To Astronomicalspectra, Christopher Sneden, Sara Lucatello, Ram S. Ram, James S. A. Brooke, Peter Bernath

Chemistry & Biochemistry Faculty Publications

New red and violet system line lists for the CN isotopologues 13C14N and 12C15N have been generated. These new transition data are combined with those previously derived for 12C14N, and applied to the determination of CNO abundances in the solar photosphere and in four red giant stars: Arcturus, the bright, very low-metallicity star HD 122563, and the carbon-enhanced metal-poor stars HD 196944 and HD 201626. When both red and violet system lines are detectable in a star, their derived N abundances are in good agreement. The mean N abundances determined in …

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Molecular Interactions With Ice: Molecular Embedding, Adsorption, Detection, And Release, K D. Gibson, Grant G. Langlois, Wenxin Li, Daniel Killelea, S J. Sibener Sep 2014

Molecular Interactions With Ice: Molecular Embedding, Adsorption, Detection, And Release, K D. Gibson, Grant G. Langlois, Wenxin Li, Daniel Killelea, S J. Sibener

Chemistry: Faculty Publications and Other Works

The interaction of atomic and molecular species with water and ice is of fundamental importance for chemistry. In a previous series of publications, we demonstrated that translational energy activates the embedding of Xe and Kr atoms in the near surface region of ice surfaces. In this paper, we show that inert molecular species may be absorbed in a similar fashion.We also revisit Xe embedding, and further probe the nature of the absorption into the selvedge. CF4 molecules with high translational energies (≥3 eV) were observed to embed in amorphous solid water. Just as with Xe, the initial adsorption rate is …

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Determining Force Field Parameters Involved With Metal Organic Framework Synthesis, Marcus A. Tubbs, David Cantu, Vanda Glezakou Aug 2014

Determining Force Field Parameters Involved With Metal Organic Framework Synthesis, Marcus A. Tubbs, David Cantu, Vanda Glezakou

STAR Program Research Presentations

Metal organic frameworks (MOFs) are synthetic materials made of a cage-like lattice with consistently spaced pores. The size of these pores are the defining characteristic of a MOF, as it determines which gases are allowed to pass through and which can be trapped. Examples of their potential use can be greenhouse gas sequestration or storage. Currently, the synthesis of MOFs is based on trial-and-error, and the successes are not well understood. We are working on building the theoretical framework that describes how a particular MOF, MIL-101, comes together during synthesis. Our initial approach was to simulate the possible reactions with …

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Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner Aug 2014

Does A Plastron Improve Heat Transfer?, Madani A. Khan, Jeffrey Alston, Andrew Guenthner

STAR Program Research Presentations

Superamphiphobic surfaces strongly repel both water and oils. In this work, aluminum coupons are processed by sanding with various grit of sand paper to impart microscale roughness. Subsequent submersion of the aluminum substrate in boiling water grows nanoscale grass-like structures. The oxide layer of Al is slightly soluble in water. During a fast diffusion/equilibrium, Al2O3 nanograss grows on the surface. A low energy coating is then deposited on the surface. The micro and nanoscale features create re-entrant structures that trap air enabling contact liquid to be in a Cassie-Baxter state. Superamphiphobicity of the samples were confirmed by …

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Heat Release Of Polyurethanes Containing Potential Flame Retardants Based On Boron And Phosphorus Chemistries, Vladimir Benin, Bastien Gardelle, Alexander Morgan Aug 2014

Heat Release Of Polyurethanes Containing Potential Flame Retardants Based On Boron And Phosphorus Chemistries, Vladimir Benin, Bastien Gardelle, Alexander Morgan

Chemistry Faculty Publications

Using a polyurethane of methylene diphenyl isocyanate and 1,3-propane diol, several new non-halogenated aromatic boron and phosphorus flame retardants were evaluated for heat release reduction potential using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods, and were then analyzed via spectroscopic methods to determine if the flame retardant was still present in the final product. PCFC testing on the resulting products showed that the flame retardant molecule can have different effects on heat release depending upon how it is mixed into the polyurethane. Some …

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Determination Of Corrosion Inhibitor Lubricity Improver In Jet Fuel By Liquid Chromatography-Electrospray Ionization Mass Spectrometry, David W. Johnson, Milissa Flake, Ryan Adams Jul 2014

Determination Of Corrosion Inhibitor Lubricity Improver In Jet Fuel By Liquid Chromatography-Electrospray Ionization Mass Spectrometry, David W. Johnson, Milissa Flake, Ryan Adams

Chemistry Faculty Publications

Military jet fuel (JP-8) is very similar to commercial jet fuel (Jet A) except for the presence of three additives, fuel system icing inhibitor, corrosion inhibitor–lubricity improver (CI-LI), and antistatic additive, which are added to improve characteristics of JP-8. Of particular interest is the CI-LI additive; the most common active ingredient is a dimer of linoleic acid. This article focuses on quantification of the active ingredient in the CI-LI additive by liquid chromatography–mass spectrometry (LC–MS). This method will allow the determination of CI-LI content in military jet fuel samples.

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Co2 Reduction Under Periodic Illumination Of Zns, Ruixin Zhou, Marcelo I. Guzman May 2014

Co2 Reduction Under Periodic Illumination Of Zns, Ruixin Zhou, Marcelo I. Guzman

Chemistry Faculty Publications

The photoreduction of CO2 to formate (HCOO–) in sphalerite (ZnS) aqueous suspensions is systematically studied in the presence of Na2S hole scavenger. A series of cut-on filters at λcut-on ≥ 280, 295, 305, 320, and 400 nm are used to measure the reaction rate of formate production. The dependence of the measured reaction rates on λcut-on indicates that a wavelength of λ = 345 nm is associated with the actual bandgap of the semiconductor nanocrystallites suspended in water. The results from apparent quantum yield measurements during periodic illumination experiments suggest that (1) valence-band …

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Using A Spreadsheet To Solve The SchröDinger Equations For The Energies Of The Ground Electronic State And The Two Lowest Excited States Of H2, Yingbin Ge, Robert C. Rittenhouse, Jacob C. Buchanan, Benjamin Livingston May 2014

Using A Spreadsheet To Solve The SchröDinger Equations For The Energies Of The Ground Electronic State And The Two Lowest Excited States Of H2, Yingbin Ge, Robert C. Rittenhouse, Jacob C. Buchanan, Benjamin Livingston

All Faculty Scholarship for the College of the Sciences

We have designed an exercise suitable for a lab or project in an undergraduate physical chemistry course that creates a Microsoft Excel spreadsheet to calculate the energy of the S0 ground electronic state and the S1 and T1 excited states of H2. The spreadsheet calculations circumvent the construction and diagonalization of the Fock matrix and thus can be accomplished by any undergraduate chemistry student with basic calculus skills. The wave functions of the S0, S1, and T1 states of H2 are constructed from the symmetry-adapted bonding and antibonding molecular …

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Selection Of The Process Parameters For The Mass Plating Of Discrete Electronic Components, Ann Hopper May 2014

Selection Of The Process Parameters For The Mass Plating Of Discrete Electronic Components, Ann Hopper

Articles

The miniaturisation of electronic components coupled with requirements for high temperature lead free soldering has forced the improvement of the termination finish of surface mount components to meet the critical demands of the electronic industry. In the present work the processing parameters necessary to plate miniature multilayer varistors (MLV’s) have been explored. The tooling selected was a “Rotary flow-thru’ plater” which achieved high volume plating with

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Electrically Controlled Formation And Release Of Admicelles For Solid Phase Extraction, Sukyeon Lee May 2014

Electrically Controlled Formation And Release Of Admicelles For Solid Phase Extraction, Sukyeon Lee

Masters Theses & Specialist Projects

Solid phase extraction is one of the most widely used methods to concentrate diluted compounds in a solution. Substances can be extracted into admicelles and hemimicelles, which are surface adsorbed micelles and surfactant monolayers, respectively. Investigations of the electrical control of surfactants on surfaces for the purpose of analyte preconcentration prior to chromatographic analysis are presented. The surfactant layer serves as the “stationary phase” in a solid phase extraction sorbent scenario. Analytes are adsorbed on this layer, and then released from the solid phase via surfactant removal. The attachment and removal of the surfactant are controlled by means of an …

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Implementation And Application Of The Mmff94 Force Field, Hongbo Zhu Apr 2014

Implementation And Application Of The Mmff94 Force Field, Hongbo Zhu

Department of Chemistry: Dissertations, Theses, and Student Research

MMFF94 is implemented for molecular mechanics calculation in the quantum chemistry polarizable force field program (QuanPol). As a general force field for organic molecules, the availability of MMFF94 expends the capability of the QuanPol program. The MMFF94 force field atom type determination and parameter matching methods are established and corresponding program routines are written in the FORTRAN language. In this implementation, the MMFF94 atom types can be determined automatically from the connectivity of the input atoms with no or minimum information of formal charges. This implementation of MMFF94 is validated using the 761 standard tests, thus is a complete implementation. …

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A Small Molecule That Binds And Inhibits The Etv1 Transcription Factor Oncoprotein, Marius C. Pop, Nicolas Stransky, Colin W. Garvie, Jean-Philippe Theurillat, Emily C. Hartman, Timothy A. Lewis, Cheng Zhong, Elizabeth K. Culyba, Fallon Lin, Douglas S. Daniels, Raymond Pagliarini, Lucienne Ronco, Angela N. Koehler, Levi A. Garraway Apr 2014

A Small Molecule That Binds And Inhibits The Etv1 Transcription Factor Oncoprotein, Marius C. Pop, Nicolas Stransky, Colin W. Garvie, Jean-Philippe Theurillat, Emily C. Hartman, Timothy A. Lewis, Cheng Zhong, Elizabeth K. Culyba, Fallon Lin, Douglas S. Daniels, Raymond Pagliarini, Lucienne Ronco, Angela N. Koehler, Levi A. Garraway

Chemistry Faculty Publications

Members of the ETS transcription factor family have been implicated in several cancers, where they are often dysregulated by genomic derangement. ETS variant 1 (ETV1) is an ETS factor gene that undergoes chromosomal translocation in prostate cancers and Ewing's sarcomas, amplification in melanomas, and lineage dysregulation in gastrointestinal stromal tumors. Pharmacologic perturbation of ETV1 would be appealing in these cancers; however, oncogenic transcription factors are often deemed “undruggable” by conventional methods. Here, we used small-molecule microarray (SMM) screens to identify and characterize drug-like compounds that modulate the biological function of ETV1. We identified the 1,3,5-triazine small molecule BRD32048 as a …

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Hydration Of The Sulfuric Acid−Methylamine Complex And Implications For Aerosol Formation, Danielle J. Bustos, Berhane Temelso, George C. Shields Apr 2014

Hydration Of The Sulfuric Acid−Methylamine Complex And Implications For Aerosol Formation, Danielle J. Bustos, Berhane Temelso, George C. Shields

Faculty Journal Articles

The binary H2SO4−H2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H …

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Capping Amyloid Β‑Sheets Of The Tau-Amyloid Structure Vqivyk With Hexapeptides Designed To Arrest Growth. An Oniom And Density Functional Theory Study, Joshua A. Plumley, Jorge Ali-Torres, Gabor Pohl, J. J. Dannenberg Mar 2014

Capping Amyloid Β‑Sheets Of The Tau-Amyloid Structure Vqivyk With Hexapeptides Designed To Arrest Growth. An Oniom And Density Functional Theory Study, Joshua A. Plumley, Jorge Ali-Torres, Gabor Pohl, J. J. Dannenberg

Publications and Research

We present ONIOM calculations using density functional theory (DFT) as the high and AM1 as the medium level that explore the abilities of different hexapeptide sequences to terminate the growth of a model for the tau-amyloid implicated in Alzheimer’s disease. We delineate and explore several design principles (H-bonding in the side chains, using antiparallel interactions on the growing edge of a parallel sheet, using all-D residues to form rippled interactions at the edge of the sheet, and replacing the H-bond donor N−H’s that inhibit further growth) that can be used individually and in combination to design such peptides that will …

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Analysis Of Localized Diabatic States Beyond The Condon Approximation For Excitation Energy Transfer Processes, Ethan Alguire, Shervin Fatehi, Yihan Shao, Joseph E. Subotnik Jan 2014

Analysis Of Localized Diabatic States Beyond The Condon Approximation For Excitation Energy Transfer Processes, Ethan Alguire, Shervin Fatehi, Yihan Shao, Joseph E. Subotnik

Chemistry Faculty Publications and Presentations

In a previous paper [Fatehi, S.; et al. J. Chem. Phys. 2013, 139, 124112], we demonstrated a practical method by which analytic derivative couplings of Boys-localized CIS states can be obtained. In this paper, we now apply that same method to the analysis of triplet–triplet energy transfer systems studied by Closs and collaborators [Closs, G. L.; et al. J. Am. Chem. Soc.1988, 110, 2652]. For the systems examined, we are able to conclude that (i) the derivative coupling in the BoysOV basis is negligible, and (ii) the diabatic coupling will likely change little over the configuration space explored …

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Van Der Waals Trilayers And Superlattices: Modification Of Electronic Structures Of Mos2 By Intercalation, Ning Lu, Hongyan Guo, Lu Wang, Xiaojun Wu, Xiao Cheng Zeng Jan 2014

Van Der Waals Trilayers And Superlattices: Modification Of Electronic Structures Of Mos2 By Intercalation, Ning Lu, Hongyan Guo, Lu Wang, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We perform a comprehensive first-principles study of the electronic properties of van der Waals (vdW) trilayers via intercalating a twodimensional (2D) monolayer (ML = BN, MoSe2, WS2, orWSe2) between a MoS2 bilayer to form various MoS2/ML/MoS2 sandwich trilayers. We find that the BN monolayer is themost effective sheet to decouple the interlayer vdW coupling of the MoS2 bilayer, and the resulting sandwich trilayer can recover the electronic structures of the MoS2 monolayer, particularly the direct-gap character. Further study of the MoS2/BN superlattices confirms the effectiveness of …

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Spontaneous Formation Of One-Dimensional Hydrogen Gas Hydrate In Carbon Nanotubes, Wenhui Zhao, Lu Wang, Jaeil Bai, Joseph S. Francisco, Xiao Cheng Zeng Jan 2014

Spontaneous Formation Of One-Dimensional Hydrogen Gas Hydrate In Carbon Nanotubes, Wenhui Zhao, Lu Wang, Jaeil Bai, Joseph S. Francisco, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We present molecular dynamics simulation evidence of spontaneous formation of quasi-one-dimensional (Q1D) hydrogen gas hydrates within single-walled carbon nanotubes (SW-CNTs) of nanometer-sized diameter (1−1.3 nm) near ambient temperature. Contrary to conventional 3D gas hydrates in which the guest molecules are typically contained in individual and isolated cages in the host lattice, the guest H2 molecules in the Q1D gas hydrates are contained within a 1D nanochannel in which the H2 molecules form a molecule wire. In particular, we show that in the (15,0) zigzag SW-CNT, the hexagonal H2 hydrate tends to form, with one H2 molecule …

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Mos2/Mx2 Heterobilayers: Bandgap Engineering Via Tensile Strain Or External Electrical Field, Ning Lu, Hongyan Guo, Lei Li, Jun Dai, Lu Wang, Wai-Ning Mei, Xiaojun Wu, Xiao Cheng Zeng Jan 2014

Mos2/Mx2 Heterobilayers: Bandgap Engineering Via Tensile Strain Or External Electrical Field, Ning Lu, Hongyan Guo, Lei Li, Jun Dai, Lu Wang, Wai-Ning Mei, Xiaojun Wu, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

We have performed a comprehensive first-principles study of the electronic and magnetic properties of two-dimensional (2D) transition-metal dichalcogenide (TMD) heterobilayers MX2/MoS2 (M = Mo, Cr, W, Fe, V; X = S, Se). For M = Mo, Cr, W; X = S, Se, all heterobilayers show semiconducting characteristics with an indirect bandgap with the exception of the WSe2/MoS2 heterobilayer which retains the directbandgap character of the constituent monolayer. For M = Fe, V; X = S, Se, the MX2/MoS2 heterobilayers exhibit metallic characters. Particular attention of this study has been focused on engineering the bandgap …

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Unraveling Crystalline Structure Of High-Pressure Phase Of Silicon Carbonate, Rulong Zhou, Bingyan Qu, Jun Dai, Xiao Cheng Zeng Jan 2014

Unraveling Crystalline Structure Of High-Pressure Phase Of Silicon Carbonate, Rulong Zhou, Bingyan Qu, Jun Dai, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Although CO2 and SiO2 both belong to group-IV oxides, they exhibit remarkably different bonding characteristics and phase behavior at ambient conditions. At room temperature, CO2 is a gas, whereas SiO2 is a covalent solid with rich polymorphs. A recent successful synthesis of the silicon-carbonate solid from the reaction between CO2 and SiO2 under high pressure [M. Santoro et al., Proc. Natl. Acad. Sci. U.S.A. 108, 7689 (2011)] has resolved a long-standing puzzle regarding whether a SixC1−xO2 compound between CO2 and SiO2 exists in nature. Nevertheless, the detailed …

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Science Classics, Mark Masthay Jan 2014

Science Classics, Mark Masthay

Chemistry Faculty Publications

An essay on the impact of the works in the Imprints and Impressions: Milestones in Human Progress, an exhibition of rare books from the collection of Stuart Rose. Exhibition was held Sept. 29-Nov. 9, 2014, at the University of Dayton.

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Passive Sampling For Quality Monitoring Of Irish Marine Waters, Philip White Jan 2014

Passive Sampling For Quality Monitoring Of Irish Marine Waters, Philip White

Doctoral

This study details the steps involved in fabrication, deployment and retrieval of mainly polydimethyl siloxane (PDMS) passive sampling devices deployed in a number of locations in and around Ireland in an attempt to derive dissolved water concentrations of contaminants in-situ. PDMS samplers were initially deployed in the Burrishoole catchment, Co. Mayo in conjunction with the collection of biological tissues and sediment to investigate the source of elevated dioxins in the catchment. Passive samplers were used to generate dissolved water concentrations of persistent organic pollutants (POPs) and also to successfully screen for the presence of dioxins in the water column. The …

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Molecular Dynamics Determination Of Edge-Sticking Parameters Of Vicinal Ice Crystals, Sam Naatz Jan 2014

Molecular Dynamics Determination Of Edge-Sticking Parameters Of Vicinal Ice Crystals, Sam Naatz

Summer Research

I will be investigating the key processes associated with the vicinal growth of ice crystals and how they are manifested at a molecular dynamics level. I will be attempting to find a vicinal edge within the quasi-liquid layer of ice crystals and assigning values to the atomistic edge-sticking parameters k+/-. My research will consist of converting code for vicinal slabs to usable Gromacs files, running MD simulations with these slabs, and analyzing the trajectories. This research will provide valuable insight to the mechanisms behind ice crystal growth and morphology.

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Ferroelectric Hexagonal And Rhombic Monolayer Ice Phases, Wen-Hui Zhao, Jaeil Bai, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng Jan 2014

Ferroelectric Hexagonal And Rhombic Monolayer Ice Phases, Wen-Hui Zhao, Jaeil Bai, Lan-Feng Yuan, Jinlong Yang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Two new phases of water, the mid-density hexagonal monolayer ice and the high-density flat rhombic monolayer ice, are observed in our molecular dynamics simulations of monolayer water confined between two smooth hydrophobic walls. These are in addition to the two monolayer ices reported previously, namely, the low-density 4∙82 monolayer ice and the high-density puckered rhombic monolayer ice (HD-pRMI). Stabilities of the structures are confirmed by ab initio computation. Importantly, both new phases and the HD-pRMI are predicted to be ferroelectric. An in-plane external electric field can further stabilize these ferroelectric monolayer ices.

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A Photoelectron Spectroscopy And Ab Initio Study Of The Structures And Chemical Bonding Of The B25 − Cluster, Zachary A Piazza, Ivan H. Popov, Wei-Li Li, Rhitankar Pal, Xiao Cheng Zeng, Alexander I. Boldyrev, Lai-Sheng Wang Jan 2014

A Photoelectron Spectroscopy And Ab Initio Study Of The Structures And Chemical Bonding Of The B25 − Cluster, Zachary A Piazza, Ivan H. Popov, Wei-Li Li, Rhitankar Pal, Xiao Cheng Zeng, Alexander I. Boldyrev, Lai-Sheng Wang

Xiao Cheng Zeng Publications

Photoelectron spectroscopy and ab initio calculations are used to investigate the structures and chemical bonding of the B25 − cluster. Global minimum searches reveal a dense potential energy landscape with 13 quasi-planar structures within 10 kcal/mol at the CCSD(T)/6-311+G(d) level of theory. Three quasi-planar isomers (I, II, and III) are lowest in energy and nearly degenerate at the CCSD(T) level of theory, with II and III being 0.8 and 0.9 kcal/mol higher, respectively, whereas at two density functional levels of theory isomer III is the lowest in energy (8.4 kcal/mol more stable than I at PBE0/6-311+G(2df) level). Comparison with …

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Satellite Observations Of Stratospheric Carbonyl Fluoride, J. J. Harrison, M. P. Chipperfield, A. Dudhia, S. Cai, S. Dhomse, C. D. Boone, Peter F. Bernath Jan 2014

Satellite Observations Of Stratospheric Carbonyl Fluoride, J. J. Harrison, M. P. Chipperfield, A. Dudhia, S. Cai, S. Dhomse, C. D. Boone, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). These molecules slowly degrade in the atmosphere, leading to the formation of HF, COF2, and COClF, which are the main fluorine-containing species in the stratosphere. Ultimately both COF2 and COClF further degrade to form HF, an almost permanent reservoir of stratospheric fluorine due to its extreme stability. Carbonyl fluoride (COF2) is the second-most abundant stratospheric "inorganic" fluorine reservoir, with main sources being the atmospheric degradation of CFC-12 (CCl2F2), HCFC-22 (CHF2Cl), and CFC-113 (CF2ClCFCl2).

This work reports the first global distributions …

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Beam-Energy Dependence Of Charge Separation Along The Magnetic Field In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, M. Zyzak, Et Al., Star Collaboration Jan 2014

Beam-Energy Dependence Of Charge Separation Along The Magnetic Field In Au + Au Collisions At Rhic, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, A. Banerjee, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, M. Zyzak, Et Al., Star Collaboration

Physics Faculty Publications

Local parity-odd domains are theorized to form inside a quark-gluon plasma which has been produced in high-energy heavy-ion collisions. The local parity-odd domains manifest themselves as charge separation along the magnetic field axis via the chiral magnetic effect. The experimental observation of charge separation has previously been reported for heavy-ion collisions at the top RHIC energies. In this Letter, we present the results of the beam-energy dependence of the charge correlations in Au+Au collisions at midrapidity for center-of-mass energies of 7.7, 11.5, 19.6, 27, 39, and 62.4 GeV from the STAR experiment. After background subtraction, the signal gradually reduces with …

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Recommended Isolated-Line Profile For Representing High-Resolution Spectroscopic Transitions (Iupac Technical Report), Jonathan Tennyson, Peter F. Bernath, Alain Campargue, Attila G. Császár, Ludovic Daumont, Robert R. Gamache, Joseph T. Hodges, Daniel Lisak, Olga V. Naumenko, Laurence S. Rothman Jan 2014

Recommended Isolated-Line Profile For Representing High-Resolution Spectroscopic Transitions (Iupac Technical Report), Jonathan Tennyson, Peter F. Bernath, Alain Campargue, Attila G. Császár, Ludovic Daumont, Robert R. Gamache, Joseph T. Hodges, Daniel Lisak, Olga V. Naumenko, Laurence S. Rothman

Chemistry & Biochemistry Faculty Publications

The report of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules is presented. The well-documented inadequacies of the Voigt profile (VP), used almost universally by databases and radiative-transfer codes, to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule have resulted in the development of a variety alternative line-profile models. These models capture more of the physics of the influence of pressure …

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