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Articles 1 - 8 of 8
Full-Text Articles in Physics
Computational Study Of The Hydration Of Sulfuric Acid Dimers: Implications For Acid Dissociation And Aerosol Formation, Berhane Temelso, Thuong Ngoc Phan, George C. Shields
Computational Study Of The Hydration Of Sulfuric Acid Dimers: Implications For Acid Dissociation And Aerosol Formation, Berhane Temelso, Thuong Ngoc Phan, George C. Shields
Berhane Temelso
We have investigated the thermodynamics of sulfuric acid dimer hydration using ab initio quantum mechanical methods. For (H2SO4)2(H2O)n where n = 0−6, we employed high-level ab initio calculations to locate the most stable minima for each cluster size. The results presented herein yield a detailed understanding of the first deprotonation of sulfuric acid as a function of temperature for a system consisting of two sulfuric acid molecules and up to six waters. At 0 K, a cluster of two sulfuric acid molecules and one water remains undissociated. Addition of a second water begins the deprotonation of the first sulfuric acid …
Cosmological Constant As Confining U(1) Charge In Two-Dimensional Dilaton Gravity, Daniel Grumiller, Robert A. Mcnees Iv, Jakob Salzer
Cosmological Constant As Confining U(1) Charge In Two-Dimensional Dilaton Gravity, Daniel Grumiller, Robert A. Mcnees Iv, Jakob Salzer
Physics: Faculty Publications and Other Works
The cosmological constant is treated as a thermodynamical parameter in the framework of two-dimensional dilaton gravity. We find that the cosmological constant behaves as a U(1) charge with a confining potential, and that such potentials require a novel Born-Infeld boundary term in the action. The free energy and other thermodynamical quantities of interest are derived, from first principles, in a way that is essentially model independent. We discover that there is always a Schottky anomaly in the specific heat and explain its physical origin. Finally, we apply these results to specific examples, like anti-de Sitter–Schwarzschild–Tangherlini black holes, Bañados-Teitelboim-Zanelli black holes …
Hydration Of The Sulfuric Acid−Methylamine Complex And Implications For Aerosol Formation, Danielle J. Bustos, Berhane Temelso, George C. Shields
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 …
First-Principles Atomistic Simulations Of Energetic Materials, Aaron Christopher Landerville
First-Principles Atomistic Simulations Of Energetic Materials, Aaron Christopher Landerville
USF Tampa Graduate Theses and Dissertations
This dissertation is concerned with the understanding of physico-chemical properties of energetic materials (EMs). Recently, a substantial amount of work has been directed towards calculations of equations of state and structural changes upon compression of existing EMs, as well as elucidating the underlying chemistry of initiation in detonating EMs. This work contributes to this effort by 1) predicting equations of state and thermo-physical properties of EMs, 2) predicting new phases of novel EMs, and 3) examining the initial stages of chemistry that result in detonation in EMs. The motivation for the first thrust, is to provide thermodynamic properties as input …
Approximate Equations Of State In Two-Temperature Plasma Mixtures, John D. Ramshaw, Andrew W. Cook
Approximate Equations Of State In Two-Temperature Plasma Mixtures, John D. Ramshaw, Andrew W. Cook
Physics Faculty Publications and Presentations
Approximate thermodynamic state relations for multicomponent atomic and molecular gas mixtures are often constructed by artificially partitioning the mixture into its constituent materials and requiring the separated materials to be in temperature and pressure equilibrium. Iterative numerical algorithms have been employed to enforce this equilibration and compute the resulting approximate state relations in single-temperature mixtures. In partially ionized gas mixtures, there is both theoretical and empirical evidence that equilibrating the chemical potentials, number densities, or partial pressures of the free electrons is likely to produce more accurate results than equilibrating the total pressures. Moreover, in many situations of practical interest …
Size-Induced Chemical And Magnetic Ordering In Individual Fe–Au Nanoparticles, Pinaki Mukherjee, Priyanka Manchanda, Pankaj Kumar, Lin Zhou, Matthew J. Kramer, Arti Kashyap, Ralph Skomski, David J. Sellmyer, Jeffrey E. Shield
Size-Induced Chemical And Magnetic Ordering In Individual Fe–Au Nanoparticles, Pinaki Mukherjee, Priyanka Manchanda, Pankaj Kumar, Lin Zhou, Matthew J. Kramer, Arti Kashyap, Ralph Skomski, David J. Sellmyer, Jeffrey E. Shield
David Sellmyer Publications
Formation of chemically ordered compounds of Fe and Au is inhibited in bulk materials due to their limited mutual solubility. However, here we report the formation of chemically ordered L12-type Fe3Au and FeAu3 compounds in Fe–Au sub-10 nm nanoparticles, suggesting that they are equilib-rium structures in size-constrained systems. The stability of these L12-ordered Fe3Au and FeAu3 com-pounds along with a previously discovered L10-ordered FeAu has been explained by a size-dependent equilibrium thermodynamic model. Furthermore, the spin ordering of these three com-pounds has been computed using ab initio first-principle calculations. All ordered compounds exhibit a …
Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger
Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger
Physics Faculty Research & Creative Works
We present experimental and theoretical results for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane. Using an (e,2e) technique in asymmetric coplanar kinematics, angular distributions of the slow ejected electron, with an energy of 20 eV, are measured when incident electrons at 250 eV ionize the target and scatter through an angle of either -10° or -15°. The data are compared with calculations performed at the molecular 3-body distorted wave level. Fair agreement between the theoretical model and the experimental measurements was observed. The similar structures for these targets provide key insights for assessing the …
Probing Secondary And Tertiary Rna Folding Using Force And Temperature, William Stephenson
Probing Secondary And Tertiary Rna Folding Using Force And Temperature, William Stephenson
Legacy Theses & Dissertations (2009 - 2024)
RNA folding is the process whereby a single stranded RNA molecule assumes its three-dimensional functional conformation. Along with the protein folding problem, the RNA folding problem remains as one of the great unsolved problems in biophysics. Generally RNA folding occurs in a hierarchical manner whereby the sequence of an RNA (primary structure) determines which regions will form helical segments (secondary structure) before further rearrangement and base pairing of secondary structure motifs (tertiary structure). Due to the intimate connection between structure and function within molecular biology, increased familiarity with the thermodynamic and kinetic factors that govern RNA folding will permit the …