Chemistry Commons^™

Three Body Interactions Of Rare Gas Solids Calculated Within The Einstein Model, Dan D'Andrea

Masters Theses

Three body interactions can become important in solids at higher pressures and densities as the molecules can come into close contact. At low temperatures, accurate studies of three body interactions in solids require averaging the three-body terms over the molecules' zero point motions. An efficient, but approximate, averaging approach is based on a polynomial approximation of the three-body term. The polynomial approximation can be developed as a function of the symmetry coordinates of a triangle displaced from its average geometry and also as a function of the Cartesian zero point displacements from each atom’s average position. The polynomial approximation approach …

Density Functional Theory Based Electrolyte Design Formulation For Lithium-Sulfur Batteries, Cynthia Ly, Carolyn Sturges, Vijay Murugesan

STAR Program Research Presentations

Lithium-ion (Li-ion) batteries are commonly used in portable electronics such as cellphones and laptops. Most Li-ion batteries operate on intercalation principle with typical theoretical specific energy of 400-600 (Wh/Kg). There is great scientific interest in lithium-sulfur (Li-S) batteries as a possible successor of traditional Li-ion batteries because Li-S holds the potential of being a very powerful (1550 Wh/kg theoretical specific energy) yet very cost-efficient battery (due the abundance and inexpensiveness of sulfur). However, one major problem in Li-S battery research is the polysulfide “shuttle phenomenon”, which is the shuttling of polysulfide species due to the dissolution of sulfide from the …

The First Potential Energy Surfaces For The C₆Hˉ-H₂ And C₆Hˉ-He Collisional Systems And Their Corresponding Inelastic Cross Sections, Kyle M. Walker, Fabien Dumouchel, François Lique, Richard Dawes

Chemistry Faculty Research & Creative Works

Molecular anions have recently been detected in the interstellar and circumstellar media. Accurate modeling of their abundance requires calculations of collisional data with the most abundant species that are usually He atoms and H₂ molecules. In this paper, we focus on the collisional excitation of the first observed molecular anion, C₆H^-, by He and H₂. Theoretical calculations of collisional cross sections rely generally on ab initio interaction potential energy surfaces (PESs). Hence, we present here the first PESs for the C₆H^--H₂ and C₆H^--He van …

A New Set Of Potential Energy Surfaces For Hco: Influence Of Renner-Teller Coupling On The Bound And Resonance Vibrational States, Steve Alexandre Ndengué, Richard Dawes, Hua Guo

Chemistry Faculty Research & Creative Works

It is commonly understood that the Renner-Teller effect can strongly influence the spectroscopy of molecules through coupling of electronic states. Here we investigate the vibrational bound states and low-lying resonances of the formyl radical treating the Renner-Teller coupled X2A' and Ã2A" states using the MultiConfiguration Time Dependent Hartree (MCTDH) method. The calculations were performed using the improved relaxation method for the bound states and a recently published extension to compute resonances. A new set of accurate global potential energy surfaces were computed at the explicitly correlated multireference configuration interaction (MRCI-F12) level and yielded remarkably close agreement with experiment in this …

2016-01-A3dsrinp-Csc-Sta-Cmb-522-Bps-542, Raymond Pulver, Neal Buxton, Xiaodong Wang, John Lucci, Jean Yves Hervé, Lenore Martin

Bioinformatics Software Design Projects

Cholesterol is carried and transported through bloodstream by lipoproteins. There are two types of lipoproteins: low density lipoprotein, or LDL, and high density lipoprotein, or HDL. LDL cholesterol is considered “bad” cholesterol because it can form plaque and hard deposit leading to arteries clog and make them less flexible. Heart attack or stroke will happen if the hard deposit blocks a narrowed artery. HDL cholesterol helps to remove LDL from the artery back to the liver.

Traditionally, particle counts of LDL and HDL plays an important role to understanding and prediction of heart disease risk. But recently research suggested that …

Benchmarking Ab Initio Computational Methods For The Quantitative Prediction Of Sunlight-Driven Pollutant Degradation In Aquatic Environments, Kasidet Trerayapiwat

Honors Projects

Understanding the changes in molecular electronic structure following the absorption of light is a fundamental challenge for the goal of predicting photochemical rates and mechanisms. Proposed here is a systematic benchmarking method to evaluate accuracy of a model to quantitatively predict photo-degradation of small organic molecules in aquatic environments. An overview of underlying com- putational theories relevant to understanding sunlight-driven electronic processes in organic pollutants is presented. To evaluate the optimum size of solvent sphere, molecular Dynamics and Time Dependent Density Functional Theory (MD-TD-DFT) calculations of an aniline molecule in di↵erent numbers of water molecules using CAM-B3LYP functional yielded excited …

Volume 08, Meghan Enzinna, Casey Dawn Gailey, Raven Collins, Chiara Enriquez, Amelia Mcconnell, Alexander Morton, Emma Beckett, Leah G. Parr, Briana Adhikusuma, Taylor Embrey, Rowan Davis, Danielle Sisson, Bianca Cherry, Melissa Cacho, Chloe Woodward, Catherine Rollins, Carson Reeher, Landon Cooper, Haley Vasquez, Marlisha Stewart, Eric Whitehead, Sabrina Walker, James Bates

Incite: The Journal of Undergraduate Scholarship

Introduction from Interim Dean Dr. Jennifer Apperson

Indigenous Peoples and the Modern Era by Meghan Enzinna

"Who Says": How Selena Gomez and the Scene Attempt to Subvert the Popular Standards of Beauty by Casey Dawn Gailey

Art by Raven Collins

Meltdown on Social Media: Amy's Baking Company Meets Kitchen Nightmares by Nathena Haddrill

Art by Chiara Enriquez

Design by Amelia Mcconnell

Worth More Than a Thousand Words: A Visual Rhetorical Discussion of Virtual Reality by Examining "Clouds Over Sidra" by Alexander Morton

Design by Emma Beckett

The Sonata: An Analysis of Piano Sonata No. 14 in C Minor, K. …

Alignment For Comprehensive Two-Dimensional Gas Chromatography (Gcxgc) With Global, Low-Order Polynomial Transformations, Davis Rempe, Stephen Reichenbach, Stephen Scott

UCARE Research Products

As columns age and differ between systems, retention times for GC x GC may vary between runs. In order to properly analyze chromatograms, it is often desirable to align chromatographic features between chromatograms. This alignment can be characterized by a mapping of retention times from one chromatogram to the retention times of another chromatogram. Alignment methods can be classified as global or local, i.e., whether the geometric differences between chromatograms are characterized by a single function for the entire chromatogram or by a combination of many functions for different regions of the chromatogram. Previous work has shown that global, low-degree …

Hydrogeochemical Modeling Of Saltwater Intrusion And Water Supply Augmentation In South Florida, Yonas T. Habtemichael

FIU Electronic Theses and Dissertations

The Biscayne Aquifer is a primary source of water supply in Southeast Florida. As a coastal aquifer, it is threatened by saltwater intrusion (SWI) when the natural groundwater flow is altered by over-pumping of groundwater. SWI is detrimental to the quality of fresh groundwater sources, making the water unfit for drinking due to mixing and reactions with aquifer minerals. Increasing water demand and complex environmental issues thus force water utilities in South Florida to sustainably manage saltwater intrusion and develop alternative water supplies (e.g., aquifer storage and recovery, ASR).

The objectives of this study were to develop and use calibrated …

Calculated Vibrational States Of Ozone Up To Dissociation, Steve Alexandre Ndengué, Richard Dawes, Xiaogang Wang, Tucker Carrington Jr., Zhigang Sun, Hua Guo

Chemistry Faculty Research & Creative Works

A new accurate global potential energy surface for the ground electronic state of ozone [R. Dawes et al., J. Chem. Phys. 139, 201103 (2013)] was published fairly recently. The topography near dissociation differs significantly from previous surfaces, without spurious submerged reefs and corresponding van der Waals wells. This has enabled significantly improved descriptions of scattering processes, capturing the negative temperature dependence and large kinetic isotope effects in exchange reaction rates. The exchange reactivity was found to depend on the character of near-threshold resonances and their overlap with reactant and product wavefunctions, which in turn are sensitive to the potential. Here …

Procesy Cieplne I Aparaty (Lab), Wojciech M. Budzianowski

Wojciech Budzianowski

-

Inżynieria Chemiczna Lab., Wojciech M. Budzianowski

Wojciech Budzianowski

-

Calculating Potential Energy Curves With Fixed-Node Diffusion Monte Carlo: Co And N₂, Andrew D. Powell, Richard Dawes

Chemistry Faculty Research & Creative Works

This study reports on the prospect for the routine use of Quantum Monte Carlo (QMC) for the electronic structure problem, applying fixed-node Diffusion Monte Carlo (DMC) to generate highly accurate Born-Oppenheimer potential energy curves (PECs) for small molecular systems. The singlet ground electronic states of CO and N₂ were used as test cases. The PECs obtained by DMC employing multiconfigurational trial wavefunctions were compared with those obtained by conventional high-accuracy electronic structure methods such as multireference configuration interaction and/or the best available empirical spectroscopic curves. The goal was to test whether a straightforward procedure using available QMC codes could …

Rcd+: Fast Loop Modeling Server, José R. López-Blanco, Alejandro J. Canosa-Valis, Yaohang Li, Pablo Chacón

Computer Science Faculty Publications

Modeling loops is a critical and challenging step in protein modeling and prediction. We have developed a quick online service (http://rcd.chaconlab.org) for ab initio loop modeling combining a coarse-grained conformational search with a full-atom refinement. Our original Random Coordinate Descent (RCD) loop closure algorithm has been greatly improved to enrich the sampling distribution towards near-native conformations. These improvements include a new workflow optimization, MPI-parallelization and fast backbone angle sampling based on neighbor-dependent Ramachandran probability distributions. The server starts by efficiently searching the vast conformational space from only the loop sequence information and the environment atomic coordinates. The generated closed loop …