Computational Chemistry Commons^™

Rate Law For Photoelectrochemical Water Splitting Over Cuo, Bo-Yuan Gao, Wen-Hua Leng

Journal of Electrochemistry

Photocatalytic splitting of water over p-type semiconductors is a promising strategy for production of hydrogen. However, the determination of rate law is rarely reported. To this purpose, copper oxide (CuO) is selected as a model photocathode in this study, and the photogenerated surface charge density, interfacial charge transfer rate constant and their relation to the water reduction rate (in terms of photocurrent) were investigated by a combination of (photo)electrochemical techniques. The results showed that the charge transfer rate constant is exponential-dependent on the surface charge density, and that the photocurrent equals to the product of the charge transfer rate constant …

Winning Results Of The 2Nd Xiamen University Short Video Abstract Contest For Science And Technology Papers, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Winning Works From Journal Of Electrochemistry: The 2Nd Xiamen University Short Video Abstract Contest For Science And Technology Journal Papers, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

2024 "Electrochemical Research Paradigms" Summer School Successfully Held, Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Upcoming Meeting-The 1St Young Investigator Symposium On Electrosynthesis, Chinese Chemical Society, Chinese Society Of Electrochemistry (Cse)

Journal of Electrochemistry

No abstract provided.

A Coarse-Grained Molecular Dynamics Study Of Gas Hydrate Formation And Dissociation, Meisam Adibifard

LSU Doctoral Dissertations

The study of gas hydrates has increased significantly over the last two decades because of their potential application in energy storage, production and transportation, water desalination, refrigeration, gas separation, etc. There is a significant interest in commercially developing natural gas hydrates because the energy content of methane hydrate reservoirs (MHRs) is at least twice that of all conventional fossil fuels combined. Additionally, due to the higher storage capacity of hydrates, it is proposed to sequester CO₂ in the form of CO₂ hydrate, thereby reducing the amount of greenhouse gases. Hence, hydrates offer a dual solution to two of …

Structure-Function Relationships In Neurodegenerative And Infectious Diseases: Biophysical Characterization Of Rna Secondary Structures By Computational Techniques, Kendy Guarinoni

Electronic Theses and Dissertations

The research described in this dissertation focuses on the investigation of the structure and dynamics of regions of RNA implicated in two diseases: COVID-19 and amyotrophic lateral sclerosis/frontotemporal dementia (ALS/FTD). Both studies sought to create experimentally corroborated models that were used to characterize the structure and dynamics of the C9orf72 repeat expansion and the s2m region in coronaviruses, respectively and provided the foundation for future work. In our work involving the s2m region of SARS-CoV-2, the virus responsible for COVID-19, we determined that the homology modeling approach commonly used to derive atomistic structures when no coordinates are available yields a …

Use Of Computational Methods To Determine The Relative Thermodynamic Stability Of Myricetin, Quercetin And 4-Methylesculetin For Use As Spin Traps, Cole Walker

Electronic Theses and Dissertations

The research conducted focused on the oxidative intermediates of antioxidants known as Myricetin, Quercetin, and 4-Methylesutin by calculating the reaction mechanism. During this research, computational quantum chemistry on selected parts for the 3 antioxidants previously mentioned were performed to find the most stable intermediate to act as a spin trap. The hypothesis is that the intermediates found can act as spin traps which will allow longer preservation of a free radical to be identified using Electron Paramagnetic Resonance (EPR) spectroscopy. This may be because the buildup of excess free radicals in a system leads them to cause damage down to …

Secondary Electron Yield Of Metals, Alloys, And Metal Oxides From First Principles Based Monte Carlo Simulations, Raul E. Gutierrez

Electrical and Computer Engineering ETDs

Density Functional Theory (DFT) based Monte Carlo (MC) simulations of the Sec-
ondary Electron Yield (SEY) of metals, alloys, and metal oxides are performed to
find material properties that could help reduce or influence the multipactor effect.
In order to accurately model the SEY of materials, knowledge of the frequency- and
momentum-dependent Energy Loss Function (qDepELF) is required. The qDepELF
is difficult to determine from experiment; however, it can be calculated from first
principles. The DFT-MC approach for simulating the secondary electron genera-
tion, propagation, and emission processes is described herein. Material properties,
which are calculated using DFT and used …

First Announcement Of 76th Annual Meeting Of The International Society Of Electrochemistry, International Society Of Electrochemistry (Ise)

Journal of Electrochemistry

No abstract provided.

Data-Driven Viewpoint For Developing Next-Generation Mg-Ion Solid-State Electrolytes, Fang-Ling Yang, Ryuhei Sato, Eric Jian-Feng Cheng, Kazuaki Kisu, Qian Wang, Xue Jia, Shin-Ichi Orimo, Hao Li

Journal of Electrochemistry

Magnesium (Mg) is a promising alternative to lithium (Li) in solid-state batteries due to its abundance and high theoretical volumetric capacity. However, the sluggish Mg-ion conduction in the lattice of solid-state electrolytes (SSEs) is one of the key challenges that hamper the development of Mg-ion solid-state batteries. Though various Mg-ion SSEs have been reported in recent years, key insights are hard to be derived from a single literature report. Besides, the structure-performance relationships of Mg-ion SSEs need to be further unraveled to provide a more precise design guideline for SSEs. In this Viewpoints article, we analyze the structural characteristics of …

Theoretical And Spectroscopic Insights Into Molybdenum- And Tungsten-Sulfur Bonding, Jesse Lepluart

Chemistry and Chemical Biology ETDs

Molybdenum and tungsten chemistry in biology is dominated by bonding interactions with sulfur and the other chalcogens. The highly-conserved structures of these enzymes’ active sites suggest an early evolution in the history of life, with molybdenum and/or tungsten enzymes likely expressed by the last universal common ancestor. Despite their active site similarities, molybdenum and tungsten enzymes catalyze a diverse array of reactions via equally diverse mechanisms. A deep understanding of the electronic structures of these enzyme active sites and their catalytic intermediates is key to understanding this remarkable chemistry.

The work presented here aims to deepen the understanding of molybdenum …

The Chemistry Of Heavy Elements: Probing Relativistic Chemical Bonding, Barbara Maria Teixeira Costa Peluzo

Chemistry Theses and Dissertations

The bottommost part of the periodic table has a unique chemistry, where the high velocities of the inner-shell electrons prevent their description by the usual Schrödinger equation. The resulting so-called relativistic effects have numerous chemical implications, on both macro and microscale, ranging from physical properties to reactivity. However, experimental probes on these intriguing atoms are limited by their natural availability and, more importantly, the danger associated with their radioactivity. Quantum chemical calculations, on the other hand, face the challenge of far more complex algebra, which demands substantial computational resources. Relativistic Hamiltonians, which act over all electrons in the system, are …

Response To Replication Stress And Maintenance Of Genome Stability By Wrn, The Werner Syndrome Protein, David K. Orren, Amrita Machwe

Markey Cancer Center Faculty Publications

Werner syndrome (WS) is an autosomal recessive disease caused by loss of function of WRN. WS is a segmental progeroid disease and shows early onset or increased frequency of many characteristics of normal aging. WRN possesses helicase, annealing, strand exchange, and exonuclease activities and acts on a variety of DNA substrates, even complex replication and re- combination intermediates. Here, we review the genetics, biochemistry, and probably physiological functions of the WRN protein. Although its precise role is unclear, evidence suggests WRN plays a role in pathways that respond to replication stress and maintain genome stability particularly in telomeric regions.

Study Of Atypical Alarmone Synthesis In Clostridioides Difficile, Declan Nathaniel Butler

Chemistry & Biochemistry Theses & Dissertations

Clostridioides difficile is a Gram-positive anaerobic bacterium that causes infections in humans that costs healthcare systems billions per year. C. difficile infection has high rates of recurrence due to multiple antibiotic resistance. When bacteria are in stressful environments, they produce hyperphosphorylated guanosine ribonucleotide signaling molecules called alarmones. The accumulation of alarmones activates the stringent response (SR), in which bacterial cells induce transcription of stress survival genes to delay growth and replication. The C. difficile SR is regulated by enzymatic activity of a bifunctional synthetase/hydrolase, RelA/SpoT homolog (RSH), and a monofunctional small alarmone synthetase (RelQ). Additionally, the SR is potentially regulated …

Dft Based Modeling Of The Heavy Atom Effect In Triplet Photosensitizers: From Fundamental Mechanics To Rational Design, Bret Andrew Steinkamp

Dissertations and Theses

Photochemistry is the study of how light interacts with molecules and includes both the absorption and release of light. This document focuses on triplet photosensitizers -- molecules that utilize the excited triplet state -- for a variety of applications including photodynamic therapy and photocatalysis. There are many factors that influence the design of triplet photosensitizers; in this work, we have developed and used a methodology for the rational design of triplet photosensitizers based on an approximation of the heavy atom effect (HAE) from density functional theory calculations and the experimentally measured singlet oxygen quantum yield (Ф_Δ).

As excited …

Development And Application Of Magnus Expansion Based Propagators For Problems In Spectroscopy And Quantum Dynamics, Taner M. Ture

Dissertations, Theses, and Capstone Projects

Stable and accurate numerical propagators of time-evolution equations in quantum mechanics are required to capture correct dynamical behavior, especially in the long time limit. Magnus expansion (ME) provides a general way to expand the real time propagator of a time dependent Hamiltonian within the exponential such that the unitarity is satisfied at any order. Integrators are developed by truncating the ME and using explicit integration of Lagrange interpolation formulas for the time dependent Hamiltonian within each time interval. The derived approximations are studied in a numerical test and compared to other available expressions. The sixth order expression is applied to …

Modeling Hydroxide In Classical Proton Hopping Simulations And Amyloid Beta Membrane Pores, Ankita Dutta

Dissertations, Theses, and Capstone Projects

H3O+ and OH- ions display anomalously large diffusion coefficients, a property that is often attributed to their ability to perform structural diffusion which allow these ions to move through aqueous solutions by sequential proton transfers, also known as ‘Grotthuss hopping’. A rearrangement of the local solvation structure is known to be the prerequisite for proton transfer events via these ions. Studying this phenomenon using classical molecular dynamics simulations that do not allow bond rearrangements poses significant obstacles. Here we use a Monte Carlo augmented classical Molecular Dynamics method called the MOBHY algorithm which allows instantaneous changes in protonation states in …

Development Of Platinum(Iv)-Gold(I)-Based Anticancer Agents, Javier E. Lopez-Hernandez

Dissertations, Theses, and Capstone Projects

Heterometallic compounds have emerged as prospective multitarget anticancer drugs. These species may display improved efficacy and physicochemical properties compared to the individual metallic fragments, while helping combat drug resistance by exerting effects on multiple pathways. In this thesis we describe the synthesis of new bi- and tri-metallic compounds based on platinum(IV) compounds containing FDA-approved platinum agents, and gold(I) derivatives with known anticancer properties. We demonstrate their toxicity and selectivity against a small panel of renal, bladder, ovarian, and breast cancer cell lines, as well as their synergistic effects. We have selected a trinuclear PtAu₂compound containing the Pt(IV) core …

Mechanistic, Biochemical, And Theoretical Studies Of Phototoxicity And Photobluing, Lloyd M. Lapoot

Dissertations, Theses, and Capstone Projects

This thesis consists of four chapters as detailed below:

Chapter 1 discusses the photoconversion of heptamethine to pentamethine cyanines and of pentamethine to trimethine cyanines. Here, we report mechanistic studies and initial experimental evidence for a previously unexplored 4-carbon truncation reaction that converts the simplest heptamethine cyanine to the corresponding trimethine cyanine. We propose a DFT-supported model describing a singlet oxygen (¹O₂) mediated formation of an allene hydroperoxide intermediate and subsequent 4-carbon loss through a retro-Diels-Alder process. Fluorescence and mass spectrometry measurements provide evidence for this direct conversion process. This 4-carbon truncation reaction adds to growing …