Tags: Physical Seminar


Disagreement on the Degradation Mechanism and Applicability of Kinetic Models for Non-Platinum Group Metal Catalysts in Polymer Electrolyte Membrane Fuel Cells

One large roadblock to the development of commercially viable hydrogen fuel cells is the cost of the platinum group metal (PGM) oxygen reduction reaction (ORR) catalysts used in proton-exchange membrane fuel cells (PEMFCs). Unfortunately, similarly active catalysts, like Fe-N-C catalysts, have suffered from stability issues limiting their use. To better understand these stability issues and design better catalysts a number of degradation…


Competition between Solvent···Solvent and Solvent···Solute Interactions in the Microhydration of the Tetrafluoroborate Anion, BF4–(H2O)n=1,2,3,4

This study systematically examines the interactions of the tetrafluoroborate anion (BF4–) with up to four water molecules (BF4–(H2O)n=1,2,3,4). Full geometry optimizations and subsequent harmonic vibrational frequency computations are performed using a variety of density functional theory (DFT) methods (B3LYP, B3LYP-D3BJ, and M06-2X) and the MP2 ab initio method with a triple-ζ correlation consistent basis set augmented with diffuse functions on…


Nitrogen Vacancy Centers as Quantum Sensors

There has been a growing interest in nitrogen-vacancy (NV) centers as high precision sensors in biology, chemistry, and physics. NV centers are naturally occurring defects in diamonds. They can detect nanoscale perturbations in local temperature, pressure, magnetic and electric fields. These quantum sensors perform optimally in ambient conditions, and their biocompatibility permits their use in vivo. The electronic states of the NV center can be…


Low Temperature Combustion of C5 Cyclic Molecules

Probing reaction mechanisms during low-temperature combustion of cyclopentane, which is a representative naphthene species, is necessary for building a broader understanding of the effect of functional groups present in C5 cyclic biofuels, such as cyclopentanol and cyclopentanone. At temperatures below 1000 K, competing reactions of naphthenes include ring-opening of initial radicals (Ṙ) and oxidation of Ṙ via reaction with O2 that yields…


Semiconductor Quantum Dots: Theory, Production, and Application

Semiconductor quantum dots are quantum confined systems that exist on the nanometer scale. A close examination into the properties of these zero-dimensional dots offers insight into their highly tunable chemistry and optics. This high tunability, in turn, promotes their use in a wide variety of interdisciplinary fields such as photovoltaics and bioimaging. Since the discovery of quantum dots, around 40 years ago, they have been the spark of much…


Construction of a Cavity-Enhanced Transient Absorption Spectrometer for Ultrafast Molecular Beam Measurements

Ultrafast spectroscopy is a powerful tool in order to probe transient dynamics of a variety of chemically relevant systems. Traditional ultrafast spectroscopy is done in either a thin film or solution phase as the concentration of the samples can easily yield high signals at relatively low powers, however these measurements are subject to solvation effects and can have a difficult time agreeing with theoretical models and other experimental…


Comparison of Multifidelity Machine Learning Models for Potential Energy Surfaces

Multifidelity modeling is a technique for fusing the information from two or more datasets into one model. It is particularly advantageous when one dataset contains few accurate results and the other contains many less accurate results. Within the context of modeling potential energy surfaces, the low fidelity dataset can be made up of a large number of inexpensive energy computations that provide adequate coverage of the N-dimensional space…


Vibrational Spectral Signatures and Ultrafast Dynamics of Strong H-bonds Investigated with Cryogenic Ion and 2D IR Spectroscopies

H-bonding interactions and proton transfer processes play central roles throughout chemistry and biology. Spectroscopic studies that directly probe strong H-bonds and proton transfer reactions, however, remain a formidable experimental challenge. We aim to characterize vibrational spectral signatures and dynamics of strong H-bonds by complementing high-resolution gas-phase techniques (cryogenic ion spectroscopy) with ultrafast time-resolved…


Gas-Phase Copper Clusters: Model for the CO2 Reduction Catalyst?


Seeking the Tricorder: Evolution of the NASA Anomaly Gas Analyzer

Dr. Jeffrey S. Pilgrim, winner of the 2023 UGA Chemistry Distinguished Alumnus Award, is President and founder of Vista Photonics, an optical instrumentation company located in Las Cruces, NM. He formed the corporation in June 2003 to develop and commercialize optical gas sensing technologies and instrumentation. Before starting Vista Photonics, Dr. Pilgrim worked as a Senior Research Scientist in a similar research and development environment…
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