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Articles 1 - 30 of 38
Full-Text Articles in Physical Chemistry
Asphalt Pavement Rejuvenation Investigated By Nuclear Magnetic Resonance Relaxometry, Catherine Skaggs
Asphalt Pavement Rejuvenation Investigated By Nuclear Magnetic Resonance Relaxometry, Catherine Skaggs
Miners Solving for Tomorrow Research Conference
Asphalt is a relatively inexpensive material commonly used for road pavements; however, asphalt ages from exposure to oxygen and UV radiation, leading to loss of elasticity, which leads to cracks and potholes. To slow or reverse asphalt aging, pavement preservation treatments are in use. It’s unclear whether these treatments truly rejuvenate the pavement structure or merely offer a short-term benefit. Nuclear Magnetic Resonance (NMR) relaxometry is an analytical technique that uses the recovery of excited nuclear magnetization as a parameter to gain insights into molecular environments. Recovery-time distributions gathered from asphalt materials show differences between regular and rejuvenated asphalt samples, …
Intramolecular Nonbonding Interactions And Geared Phenyl Twisting In Para-Disubstituted 1,4-Diphenylazines: Electron Correlation Effects On Molecular Conformations And Enantiomerization, Kaidi Yang, Harmeet Bhoday, Rainer Glaser
Intramolecular Nonbonding Interactions And Geared Phenyl Twisting In Para-Disubstituted 1,4-Diphenylazines: Electron Correlation Effects On Molecular Conformations And Enantiomerization, Kaidi Yang, Harmeet Bhoday, Rainer Glaser
Chemistry Faculty Research & Creative Works
The results are reported of potential energy surface (PES) analyses of six symmetrical azines Yp − Ph − RC=N − N=CR − Ph − Yp, namely, the benzaldehyde azines 1H, 2H, and 8H with R = H and the acetophenone azines 1M, 2M, and 8M with R = Me. The Y substituents Cl (1), Br (2), and Me (8) were studied because sets of polymorphs I (C2-symmetry, azine twist τ ≈ 135 ± 10°, disrotatory phenyl twists ϕi ≠ 0°) and II (Ci-symmetry, τ = 180°, conrotatory ϕi ≠ 0°) were crystallized for these three azines. The …
Long-Range Fit: A Software Package For The Representation And Study Of Long-Range Molecular Interactions, Adrian L. Batista-Planas, Ernesto Quintas-Sánchez, Richard Dawes
Long-Range Fit: A Software Package For The Representation And Study Of Long-Range Molecular Interactions, Adrian L. Batista-Planas, Ernesto Quintas-Sánchez, Richard Dawes
Chemistry Faculty Research & Creative Works
Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions with electrostatic, induction, and dispersion as the main components play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via a multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed long-range-fit (LRF), an interactive and user-friendly …
Theoretical Study Of Long-Range Molecular Interactions, Adrian Luis Batista-Planas
Theoretical Study Of Long-Range Molecular Interactions, Adrian Luis Batista-Planas
Doctoral Dissertations
Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions—with electrostatic, induction, and dispersion as main components—play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well-established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed Long-Range-Fit (LRF), an interactive and user-friendly software package designed to automate …
Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis
Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
We report a new class of graphitic carbon aerogel precursors based on iron oxide-doped poly(phloroglucinol-terephthalaldehyde–urethane) (T-POL/PU-FeOx) networks. The hybrid polymeric network incorporates a rigid aromatic triisocyanate, tris(4-isocyanatophenyl)methane, which reacts in situ with the hydroxyl groups of phloroglucinol to form a polyurethane-containing framework. Monolithic aerogels derived from this system undergo catalytic graphitization at significantly reduced temperatures (800–1500 °C) compared to conventional graphitization (2500–3300 °C). An oxidative ring fusion aromatization step (240 °C, air) prior to pyrolysis enhanced the degree of graphitization. The resulting graphitic aerogels were characterized by XRD, Raman spectroscopy, TGA, TEM, SEM, XPS, and N₂ sorption porosimetry. Compared to …
Collisional Excitation Of Hcn By Co To Refine The Modeling Of Cometary Comae, Francesca Tonolo, Ernesto Quintas-Sánchez, Adrian Batista-Planas, Richard Dawes, François Lique
Collisional Excitation Of Hcn By Co To Refine The Modeling Of Cometary Comae, Francesca Tonolo, Ernesto Quintas-Sánchez, Adrian Batista-Planas, Richard Dawes, François Lique
Chemistry Faculty Research & Creative Works
We present the first dataset of collisional (de)-excitation rate coefficients of HCN induced by CO, one of the main perturbing gases in cometary atmospheres. The dataset spans the temperature range of 5–50 K. It includes both state-to-state rate coefficients involving the lowest ten and nine rotational levels of HCN and CO, respectively, and the so-called "thermalized" rate coefficients over the rotational population of CO at each kinetic temperature. The derivation of these coefficients exploited the good performance of the statistical adiabatic channel model (SACM) on top of an accurate interaction potential computed at the CCSD(T)-F12b/CBS level of theory. The reliability …
Revisiting The Spin–Lattice Relaxation Of Homonuclear In-Phase And Antiphase Nmr Magnetization, Lauren M. Kehoe, Zachary G. Mayes, Kelsey E. Brakensiek, Emma L. Ellis, Adam J. Alderfer, Lingyu Chi, Klaus Woelk
Revisiting The Spin–Lattice Relaxation Of Homonuclear In-Phase And Antiphase Nmr Magnetization, Lauren M. Kehoe, Zachary G. Mayes, Kelsey E. Brakensiek, Emma L. Ellis, Adam J. Alderfer, Lingyu Chi, Klaus Woelk
Chemistry Faculty Research & Creative Works
Hyperpolarization techniques such as dynamic nuclear polarization (DNP), chemically induced dynamic nuclear polarization (CIDNP), and parahydrogen-induced polarization (PHIP) enhance the sensitivity of NMR spectroscopy and MRI, but the associated antiphase magnetization patterns often relax faster than those of conventional in-phase signals. This study analyzes the spin–lattice relaxation matrix for single-quantum transitions in an isolated, weakly coupled two-spin AX system to identify eigenvectors and eigenvalues that govern the time evolution of in-phase and antiphase longitudinal magnetization. The analysis predicts that AX antiphase magnetization, such as that generated by PHIP hydrogenations in high magnetic field, can relax up to twice as fast …
High-Capacity, Reversible, And Energy-Efficient Water Vapor Sorption By Hierarchical Micro-To-Macroporous Carbon Aerogels From Polybenzoxazine And Polybenzodiazine, Vaibhav A. Edlabadkar, Rushi U. Soni, Stephen Y. Owusu, A. B.M.Shaheen Ud Doulah, Nicholas Leventis, Chariklia Sotiriou-Leventis
High-Capacity, Reversible, And Energy-Efficient Water Vapor Sorption By Hierarchical Micro-To-Macroporous Carbon Aerogels From Polybenzoxazine And Polybenzodiazine, Vaibhav A. Edlabadkar, Rushi U. Soni, Stephen Y. Owusu, A. B.M.Shaheen Ud Doulah, Nicholas Leventis, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
Quantitative, reversible water vapor sorption is in rising demand for applications ranging from home appliances to atmospheric water harvesting. However, most sorbents suffer from low water-uptake capacities, nonreusability, and especially high regeneration temperatures. This study addresses this challenge by introducing polybenzoxazine- (PBO) and polybenzodiazine-derived (PBDAZ) carbon aerogels as reversible high-capacity desiccants. PBO and PBDAZ aerogels were prepared from structurally related monomers via HCl-catalyzed ring opening polymerization. Both types of aerogels were first aromatized at 200–240 °C under air or O2 and then were carbonized at 800 °C under Ar. These as-prepared carbon aerogels were further etched at 1000 °C under …
Efficient Decontamination Of Organophosphate-Based Pesticides And Nerve Agent Simulants Mediated By N-Containing Nucleophiles, Emmanuel Kingsley Darkwah, Puspa Aryal, Saidulu Todeti, Jared Kenik, Samuel Insall, V. Prakash Reddy, Chariklia Sotiriou-Leventis
Efficient Decontamination Of Organophosphate-Based Pesticides And Nerve Agent Simulants Mediated By N-Containing Nucleophiles, Emmanuel Kingsley Darkwah, Puspa Aryal, Saidulu Todeti, Jared Kenik, Samuel Insall, V. Prakash Reddy, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
There is a growing interest in developing safer and more effective decontaminating agents for organophosphate-based pesticides and nerve agents. In this study, we present an effective method for the nonaqueous decontamination of these compounds using small-molecule-based decontaminating agents under ambient conditions. Our approach utilizes aryl and heteroaryl carboxaldehyde hydrazones and hydrazides to effectively hydrolyze nerve agent simulants into their nontoxic degradation products. The effectiveness of this method was evaluated using a range of nerve agent simulants, including dimethyl 4-nitrophenyl phosphate (DMNP), dimethyl methyl phosphonate (DMMP), and triphenyl phosphate (TPhP). In the presence of the heteroaryl hydrazone, the rate of hydrolysis …
A Promising Statistical Approach For Studying The Collisional Excitation Induced By Co: Application To The Cs-Co System, Amélie Godard Palluet, Richard Dawes, Ernesto Quintas-Sánchez, Adrian Batista-Planas, François Lique
A Promising Statistical Approach For Studying The Collisional Excitation Induced By Co: Application To The Cs-Co System, Amélie Godard Palluet, Richard Dawes, Ernesto Quintas-Sánchez, Adrian Batista-Planas, François Lique
Chemistry Faculty Research & Creative Works
The calculations of rate coefficients for the interpretation of molecular spectra are a recognized computationally expensive task. This is particularly true for media like comets, where the dominant species (CO, CO2, and H2O) have relatively high masses. Currently, no clear methodology exists to treat the collisional excitation of heavy species at low temperatures, thus limiting the number of collisional studies on such species. We present here a promising statistical approach to determine collisional rate coefficients of heavy systems as an alternative to fully quantum calculations when heavy projectiles such as CO are considered. This is illustrated …
An Open-Framework Iron-Selenite As Cathode For Li- Ion Batteries, Sutapa Bhattacharya, Aleksandr V. Chernatynskiy, Amitava Choudhury
An Open-Framework Iron-Selenite As Cathode For Li- Ion Batteries, Sutapa Bhattacharya, Aleksandr V. Chernatynskiy, Amitava Choudhury
Miners Solving for Tomorrow Research Conference
No abstract provided.
The Effect Of Nanomorphology As Quantified Via The K‑Index On The Drug Delivery Properties Of Isocyanate-Derived Aerogels, Stephen Y. Owusu, A. B. M. Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Kamden J. George, Chariklia Sotiriou-Leventis
The Effect Of Nanomorphology As Quantified Via The K‑Index On The Drug Delivery Properties Of Isocyanate-Derived Aerogels, Stephen Y. Owusu, A. B. M. Shaheen Ud Doulah, Vaibhav A. Edlabadkar, Kamden J. George, Chariklia Sotiriou-Leventis
Miners Solving for Tomorrow Research Conference
No abstract provided.
Products Of Laser Ablated Actinides And Actinide Comparators In The Presence Of Carbonyl Sulfide Characterized By Rotational Spectroscopy, Joshua Edward Isert
Products Of Laser Ablated Actinides And Actinide Comparators In The Presence Of Carbonyl Sulfide Characterized By Rotational Spectroscopy, Joshua Edward Isert
Doctoral Dissertations
As the consumption of energy continues to rise globally, so too has interest in alternative energy sources such as nuclear power. However, a fundamental understanding of the actinide series is needed in order to safely and efficiently utilize these elements. Rotational or microwave spectroscopy, depending on if one is speaking of the physical outcome of the experiment or the region of the electromagnetic spectrum being operated in, is a gas phase molecular study utilized for structural determination. This technique can be utilized to gain an in depth understanding of bonding within the actinide series. However, when studying species that are …
Tailoring Selected Aerogels To Targeted Applications, Stephen Yaw Owusu
Tailoring Selected Aerogels To Targeted Applications, Stephen Yaw Owusu
Doctoral Dissertations
Aerogels are ultra-lightweight, porous solid materials characterized by a three-dimensional nanostructured network. Owing to their exceptional physical and chemical properties, aerogels have garnered considerable attention within the materials science community and were recognized by IUPAC in 2022 as one of the top ten emerging technologies in chemistry. Although numerous aerogels have been synthesized, only a few have been effectively tailored for specific applications. Optimizing the properties of known aerogels for targeted uses remains challenging. This dissertation investigates strategies for tailoring aerogels derived from isocyanate-benzoxazine, benzodiazine, and phenolic resins to meet the requirements of various advanced applications. The approaches employed include …
Polybenzodiazine Aerogels: All-Nitrogen Analogues Of Polybenzoxazines - Synthesis, Characterization, And Their Application In Carbon Dioxide Capture, Vaibhav Edlabadkar
Polybenzodiazine Aerogels: All-Nitrogen Analogues Of Polybenzoxazines - Synthesis, Characterization, And Their Application In Carbon Dioxide Capture, Vaibhav Edlabadkar
Doctoral Dissertations
"The rapidly risen concentration of carbon dioxide in the atmosphere over recent years contributed to global warming and ocean acidification. Carbon capture is viewed as an essential tool from keeping atmospheric CO2 levels from rising further. This thesis focuses on the development of new materials for high capacity and selective adsorption of CO2. One such material was based on a newly synthesized tetrahydroquinazoline (THQ), which was designed as an all-nitrogen analogue of main-stream benzoxazine monomers. THQ solutions in DMF gelled at 100 °C via HCl-catalyzed ring opening polymerization to polybenzodiazine (PBDAZ) wet gels, which were dried in …
Development Of Dual-Scan Nuclear Magnetic Resonance (Nmr) Pulse Programs For Spin-Lattice Relaxation Measurements, Zachary Mayes
Development Of Dual-Scan Nuclear Magnetic Resonance (Nmr) Pulse Programs For Spin-Lattice Relaxation Measurements, Zachary Mayes
Doctoral Dissertations
This research develops and refines the Split Inversion Pulse and Recovery (SIP R) methodology for spin-lattice relaxation (T₁) measurements in NMR spectroscopy. SIP R introduces a two-scan difference technique using a split inversion pulse sequence, where the 180° pulse is split into two 90° pulses phase-shifted with respect to each other. This approach simplifies data fitting, requiring only two parameters to extract T₁ values, compared to the traditional inversion-recovery method, which needs three. The SIP-R-DS and SIP-R-S adaptations extend this framework by incorporating selective NMR resonance excitations, enhancing its applicability to cross-polarization experiments and enabling unobstructed NOE measurements. These adaptations …
Fitting Quality Of Nmr Relaxation Data To Differentiate Asphalt Binders, Rebecca M. Herndon, Kevin Lai, Magdy Abdelrahman, Klaus Woelk
Fitting Quality Of Nmr Relaxation Data To Differentiate Asphalt Binders, Rebecca M. Herndon, Kevin Lai, Magdy Abdelrahman, Klaus Woelk
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt binder performance grades (PGs) are important metrics in designing pavements for effective transportation infrastructure. the PG system relies on the binder's stiffness and is determined through energy- and time-intensive physical testing. Physical properties, like stiffness, can also be determined by spin–lattice NMR relaxometry, a non-destructive chemical method. NMR relaxometry can quantify the molecular mobility of materials by determining relaxation times from exponential decays of excited nuclear magnetization. While relaxation times have been used to determine physical properties of materials, a quantitative relation to the PG grades of asphalt binder is yet to be established. in this study, T1 NMR …
Multiphase Electrochemical Li-Ion Intercalation In Iron Selenite: Evidence Of Fe³⁺/⁴⁺ Redox And Single-Crystal-To-Single-Crystal Topochemical Transformation During Chemical Lithiation, Sutapa Bhattacharya, Aleksandr V. Chernatynskiy, Amitava Choudhury
Multiphase Electrochemical Li-Ion Intercalation In Iron Selenite: Evidence Of Fe³⁺/⁴⁺ Redox And Single-Crystal-To-Single-Crystal Topochemical Transformation During Chemical Lithiation, Sutapa Bhattacharya, Aleksandr V. Chernatynskiy, Amitava Choudhury
Physics Faculty Research & Creative Works
An iron selenite-based cathode compound, LiFe(SeO3)2, is synthesized via a simple hydrothermal route. The bulk purity of the compound is confirmed by powder X-ray diffraction (PXRD), Mössbauer spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The crystal structure determined from the single-crystal X-ray diffraction and Rietveld refinement of synchrotron PXRD data perfectly matches the previously reported structure in the I4̅2d space group. The crystal structure is built up of edge-sharing of FeO6 octahedra and LiO4 tetrahedra interconnected by SeO3 trigonal pyramidal units, forming a three-dimensional open framework network with channels through all three axes. …
Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. The aging of asphalt binder during construction is traditionally modeled by rolling thin film oven (RTFO) testing, while aging during service life is modeled by pressure aging vessel (PAV) testing. Comparing these models to the aging of binders in actual pavements is limited because, to be used for current testing, binders must be separated from the pavement's aggregate by solvent extraction. Solvent extraction will, at …
Nuclear Magnetic Resonance (Nmr) Assessment Of Bio And Crude Oil-Based Rejuvenation, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Nuclear Magnetic Resonance (Nmr) Assessment Of Bio And Crude Oil-Based Rejuvenation, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt binders in pavements lose their stability through aging and eventually fail in the field. Using nuclear magnetic resonance (NMR) to monitor the primary longitudinal relaxation time of asphalt samples and the ratio of material that carries this primary relaxation time has been shown to indicate the impact of ultraviolet (UV) radiation on the aging of asphalt pavements. Longitudinal NMR relaxation was used to investigate two types of proposed asphalt rejuvenators, a bio-oil-based rejuvenator and a crude-oil-based rejuvenator. Two different binders with the performance grades (PG) 64-22 and 76-22 were considered for their interactions with the rejuvenators. After 72 h …
Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Asphalt-Binder Mixtures Evaluated By T1 Nmr Relaxometry, Rebecca M. Herndon, Jay Balasubramanian, Magdy Abdelrahman, Klaus Woelk
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Asphalt pavements make up a majority of the essential transportation systems in the US. Asphalt mixtures age and degrade over time, reducing the pavement performance. Pavement performance critically depends on the aging of asphalt binder. the aging of asphalt binder during construction is traditionally modeled by rolling thin film oven (RTFO) testing, while aging during service life is modeled by pressure aging vessel (PAV) testing. Comparing these models to the aging of binders in actual pavements is limited because, to be used for current testing, binders must be separated from the pavement's aggregate by solvent extraction. Solvent extraction will, at …
Physical And Chemical Methods To Assess Performance Of Tpo-Modified Asphalt Binder, Rebecca M. Herndon, Jay Balasubramanian, Klaus Woelk, Magdy Abdelrahman
Physical And Chemical Methods To Assess Performance Of Tpo-Modified Asphalt Binder, Rebecca M. Herndon, Jay Balasubramanian, Klaus Woelk, Magdy Abdelrahman
Chemistry Faculty Research & Creative Works
The Demand for Effective Asphalt Additives is Growing as Road Infrastructure Ages and More Sustainable Pavement Solutions Are Needed. Tire Pyrolysis Oil (TPO) is an Example Material that Has Been Gaining Attention as a Potential Asphalt Additive. While Physical Performance Grade (PG) Temperatures Are the Predominant Performance Requirements for Asphalt Binders, Chemical Properties Are Also Significant in the Evaluation of Asphalt Performance. There is a Need to Chemically Characterize the Aging of Asphalt Binders Modified with TPO and Link Chemical Changes in Binder Components to Binder Performance. This Study Compares 2%, 4%, and 8% TPO and Asphalt Binder Blends Via …
Ab Initio Quantum Scattering Calculations And A New Potential Energy Surface For The Hcl(X¹Σ+)-O2( X 3 Σ G − ) System: Collision-Induced Line Shape Parameters For O2-Perturbed R(0) 0-0 Line In H35cl, Artur Olejnik, Hubert Jóźwiak, Maciej Gancewski, Ernesto Quintas-Sánchez, Richard Dawes, Piotr Wcisło
Ab Initio Quantum Scattering Calculations And A New Potential Energy Surface For The Hcl(X¹Σ+)-O2( X 3 Σ G − ) System: Collision-Induced Line Shape Parameters For O2-Perturbed R(0) 0-0 Line In H35cl, Artur Olejnik, Hubert Jóźwiak, Maciej Gancewski, Ernesto Quintas-Sánchez, Richard Dawes, Piotr Wcisło
Chemistry Faculty Research & Creative Works
The Remote Sensing of Abundance and Properties of HCl—the Main Atmospheric Reservoir of Cl Atoms that Directly Participate in Ozone Depletion—is Important for Monitoring the Partitioning of Chlorine between "Ozone-Depleting" and "Reservoir" Species. Such Remote Studies Require Knowledge of the Shapes of Molecular Resonances of HCl, Which Are Perturbed by Collisions with the Molecules of the Surrounding Air. in This Work, We Report the First Fully Quantum Calculations of Collisional Perturbations of the Shape of a Pure Rotational Line in H35Cl Perturbed by an Air-Relevant Molecule [As the First Model System We Choose the R(0) Line in HCl Perturbed by …
Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier
Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier
Chemistry Faculty Research & Creative Works
Interstellar Anions Play an Important Role in Astrochemistry as Being Tracers of the Physical and Chemical Conditions in Cold Molecular Clouds and Circumstellar Gas. the Local Thermodynamic Equilibrium is Generally Not Fulfilled in Media Where Anions Are Detected and Radiative and Collisional Data Are Required to Model the Observed Lines. the C2H- Anion Has Not Yet Been Detected in the Interstellar Medium; However, Collisional Data Could Be Used for Non-LTE Models that Would Help in Identifying the Most Intense Lines. for This Purpose, We Have Computed the First 4D Potential Energy Surface (PES) of the C2H--H2 Complex using an Explicitly …
Rovibrational States Calculations Of The H2o-Hcn Heterodimer With The Multiconfiguration Time Dependent Hartree Method, Hervé Tajouo Tela, Ernesto Quintas-Sánchez, Marie Lise Dubernet, Yohann Scribano, Richard Dawes, Fabien Gatti, Steve Ndengué
Rovibrational States Calculations Of The H2o-Hcn Heterodimer With The Multiconfiguration Time Dependent Hartree Method, Hervé Tajouo Tela, Ernesto Quintas-Sánchez, Marie Lise Dubernet, Yohann Scribano, Richard Dawes, Fabien Gatti, Steve Ndengué
Chemistry Faculty Research & Creative Works
Water and hydrogen cyanide are two of the most common species in space and the atmosphere with the ability of binding to form dimers such as H2O-HCN. In the literature, while calculations characterizing various properties of the H2O-HCN cluster (equilibrium distance, vibrational frequencies and rotational constants) have been done in the past, extensive calculations of the rovibrational states of this system using a reliable quantum dynamical approach have yet to be reported. In this work, we intend to mend that by performing the first calculation of the rovibrational states of the H2O-HCN van der …
Temperature Dependence Of The Electronic Absorption Spectrum Of No2, Steve Ndengué, Ernesto Quintas Sánchez, Richard Dawes, Christopher C. Blackstone, David L. Osborn
Temperature Dependence Of The Electronic Absorption Spectrum Of No2, Steve Ndengué, Ernesto Quintas Sánchez, Richard Dawes, Christopher C. Blackstone, David L. Osborn
Chemistry Faculty Research & Creative Works
The nitrogen dioxide (NO2) radical is composed of the two most abundant elements in the atmosphere, where it can be formed in a variety of ways including combustion, detonation of energetic materials, and lightning. Relevant also to smog and ozone cycles, together these processes span a wide range of temperatures. Remarkably, high-resolution NO2 electronic absorption spectra have only been reported in a narrow range below about 300 K. Previously, we reported [ J. Phys. Chem. A 2021, 125, 5519−5533 ] the construction of quasi-diabatic potential energy surfaces (PESs) for the lowest four electronic states (X̃, Ã, B̃, …
Fluorination Of Rubisco-Mimetic Co2 Capture Systems. Theoretical And Experimental Studies Of Ammonium Ion Acidity Depression And Carbamylation, Brian Michael Jameson
Fluorination Of Rubisco-Mimetic Co2 Capture Systems. Theoretical And Experimental Studies Of Ammonium Ion Acidity Depression And Carbamylation, Brian Michael Jameson
Doctoral Dissertations
"RuBisCO-inspired CO2 capture and release (CCR) systems featuring amines have been developed for the purpose of reversable CO2 capture from air. The enzyme active site consists of the tetrapeptide sequence Lys-Asp-Asp-Glu. The Lys sidechain amine undergoes carbamylation and an Mg2+ cation stabilizes the resulting carbamate. The Na-acyl-lysinyl-aspratyl-aspartyl-glutamide (Lys-Asp-Asp-Glu, KDDE) peptide featured maximum capture at pH ≈ 10; a pH region too high for Mg2+ ions to remain in solution. This work aims to achieve pKa depression by introducing fluorine in the proximity of the lysine’s sidechain amine. A comparative analysis was made of butylamine, …
Perfect Polar Alignment Of Parallel Beloamphiphile Monolayers: Synthesis, Characterization, And Crystal Architectures Of Unsymmetrical Phenoxy-Substituted Acetophenone Azines, Harmeet Bhoday, Michael Lewis, Steven P. Kelley, Rainer Glaser
Perfect Polar Alignment Of Parallel Beloamphiphile Monolayers: Synthesis, Characterization, And Crystal Architectures Of Unsymmetrical Phenoxy-Substituted Acetophenone Azines, Harmeet Bhoday, Michael Lewis, Steven P. Kelley, Rainer Glaser
Chemistry Faculty Research & Creative Works
It remains a great challenge to achieve polar order in organic molecular crystals because anti-parallel alignment of side-by-side molecules is intrinsically preferred. We have addressed this problem with a rational design that focuses on the polar stacking of parallel beloamphiphile monolayers (PBAMs) with strong lateral quadrupole-quadrupole attractions. We employ arene-arene interactions as lateral synthons. The first successes were achieved with unsymmetrical donor (X), acceptor (Y) substituted acetophenone azines which form polar PBAMs with double T-contacts between the azines. Near-perfect alignment was achieved with the methoxy series of (MeO, Y)-azines with Y=Cl, Br, I. Here, we report on the synthesis, the …
Discovery Of An Olivine-Type Lithium Manganese Thiophosphate, Limnps4,: Via A Building Block Approach, Srikanth Balijapelly, Kartik Ghosh, Aleksandr V. Chernatynskiy, Amitava Choudhury
Discovery Of An Olivine-Type Lithium Manganese Thiophosphate, Limnps4,: Via A Building Block Approach, Srikanth Balijapelly, Kartik Ghosh, Aleksandr V. Chernatynskiy, Amitava Choudhury
Physics Faculty Research & Creative Works
An olivine-type orthothiophospate LiMnPS4 has been synthesized for the first time through a building block approach by reacting preformed ternary lithium thiophospate with MnCl2. Diffuse reflectance measurements show an optical band gap of 2.36 eV, which is further confirmed by DFT calculations. Irreversible weak ferromagnetic ordering and metamagnetism are verified through preliminary magnetic measurements.
Relating Detonation Parameters To The Detonation Synthesis Of Nanomaterials, Martin Langenderfer
Relating Detonation Parameters To The Detonation Synthesis Of Nanomaterials, Martin Langenderfer
Doctoral Dissertations
“This research investigates the physical and chemical processes that contribute to the detonation synthesis of silicon carbide nanoparticles. Bulk production of SiC nanoparticles through detonation is possible due to pressures achieved over 20 GPa and temperatures over 2000 K as well as quenching rates in excess of 13 billion K/second. These conditions catalyze reaction and bottom-up molecular growth while retaining particles < 100 nm in diameter. In this work, detonation synthesis of SiC was demonstrated by incorporation of polycarbosilane, an SiC precursor material, into an RDX/TNT explosive matrix prior to detonation. Detonation Synthesis of SiC was also accomplished by reacting elemental silicon with carbon liberated by the detonation of negatively oxygen balanced TNT. Hydrodynamic simulation of a 60:40 mass ratio RDX/TNT detonation created conditions thermodynamically suitable to produce cubic silicon carbide within the first 500 nanoseconds after the passage of the detonation wave while carbon remains chemically reactive for molecular formation. Simulations and experimental tests indicated that loading configuration and impedance mismatch of the precursor additives used in detonation synthesis results in conditions in the additives that exceed the accepted detonation pressure of the explosive by greater than three times. Finally, a full factorial experimental design showed increasing silicon concentration, reducing silicon size, and reducing oxygen balance by adjusting the ratio of RDX to TNT decreased the explosives detonation pressure by 20% and increased the soot yield and concentration of SiC observed in the detonation products by 82% and 442% respectively”--Abstract, page iv.