Atomic, Molecular and Optical Physics Commons^™

Spectroscopy Of Highly Charged Ions For Astrophysical And Laboratory Plasma Diagnostics, Yang Yang

All Dissertations

Electron beam ion traps (EBITs) are small-scale laboratory devices that create and trap highly charged ions (HCI) for spectroscopic studies. These devices create plasma conditions resembling astrophysical environments like stellar winds and supernova remnants, providing valuable insights into astrophysical plasma. Theoretical models for such systems require incorporating relativistic and quantum electrodynamics effects, making experimental studies of HCIs essential for benchmarking these theories.

Spectral analysis of astrophysical and laboratory plasma requires understanding the ionization balance. Accurate atomic data, including excitation, ionization, and recombination cross sections, along with precise knowledge of operating conditions such as electron beam density, electron beam energy, and …

Study Of Highly Charged Ion Charge Exchange With Applications To X-Ray Astrophysics, Richard Mattish

All Dissertations

Highly charged ions (HCIs) exist in many hot astrophysical environments where they play an important role in plasma dynamics. Charge exchange involving highly charged ions has been shown to be responsible for many observed X-ray emissions from a variety of astrophysical sources. Proper modeling of these environments requires an understanding of this process, including the electronic structure of each ion species as well as their charge exchange cross sections. This dissertation investigates charge exchange processes with highly charged ions which are present in astrophysical environments via a laboratory-based study.

The Clemson University electron beam ion trap (CUEBIT) laboratory was utilized …

High-Power Laser Cooling And Temperature-Dependent Fluorescence Studies Of Ytterbium Doped Silica, Brian Topper

Optical Science and Engineering ETDs

Experimental observation of optical refrigeration using ytterbium doped silica glass in recent years has created a new solution for heat mitigation in high-power laser systems, nonlinear fiber experiments, integrated photonics, and precision metrology. Current efforts of different groups focus on compositional optimization, fiber fabrication, and investigating how much silica can be cooled with a laser. At the start of this work, the best effort in laser cooling ytterbium doped silica saw cooling by 6 K from room temperature. This dissertation follows the experimental efforts that culminated in the increase of this initial record by one order of magnitude. Comprehensive spectroscopic …

Portable Optical Spectroscopic Assay For Non-Destructive Measurement Of Key Metabolic Parameters On In Vitro Cancer Cells And Organotypic Fresh Tumor Slices, Jing Yan, Carlos Frederico Lima Goncalves, Madison O. Korfhage, Zahid Hasan, Teresa Whei-Mei Fan, Xiaoqin Wang, Caigang Zhu

Markey Cancer Center Faculty Publications

To enable non-destructive metabolic characterizations on in vitro cancer cells and organotypic tumor models for therapeutic studies in an easy-to-access way, we report a highly portable optical spectroscopic assay for simultaneous measurement of glucose uptake and mitochondrial function on various cancer models with high sensitivity. Well-established breast cancer cell lines (MCF-7 and MDA-MB-231) were used to validate the optical spectroscopic assay for metabolic characterizations, while fresh tumor samples harvested from both animals and human cancer patients were used to test the feasibility of our optical metabolic assay for non-destructive measurement of key metabolic parameters on organotypic tumor slices. Our optical …

Simulating Strongly Coupled Many-Body Systems With Quantum Algorithms, Manqoba Qedindaba Hlatshwayo

Dissertations

The complexity of the nuclear many-body problem is a severe obstacle to finding a general and accurate numerical approach needed to simulate medium-mass and heavy nuclei. Even with the advent of exascale classical computing, the impediment of exponential growth of the Hilbert space renders the problem intractable for most classical calculations. In the last few years, quantum algorithms have become an attractive alternative for practitioners because quantum computers are more efficient in simulating quantum physics than classical computers. While a fully fault-tolerant universal quantum computer will not be realized soon, this dissertation explores quantum algorithms for simulating nuclear physics suitable …

Study Of Radiation Effects In Gan-Based Devices, Han Gao

Electrical Engineering Theses and Dissertations

Radiation tolerance of wide-bandgap Gallium Nitride (GaN) high-electron-mobility transistors (HEMT) has been studied, including X-ray-induced TID effects, heavy-ion-induced single event effects, and neutron-induced single event effects. Threshold voltage shift is observed in X-ray irradiation experiments, which recovers over time, indicating no permanent damage formed inside the device. Heavy-ion radiation effects in GaN HEMTs have been studied as a function of bias voltage, ion LET, radiation flux, and total fluence. A statistically significant amount of heavy-ion-induced gate dielectric degradation was observed, which consisted of hard breakdown and soft breakdown. Specific critical injection level experiments were designed and carried out to explore …

Density Dependence And Dynamics Of Dipole-Dipole Interactions Among Rydberg Atoms, Hannah Conley

Physics and Astronomy Summer Fellows

After trapping atoms, exciting them to an initial high-energy Rydberg state, and allowing them a brief time to exchange energy with each other through dipole-dipole interactions, we observe how their energies are redistributed among various energy levels. The measurements we make in this physical experiment do not give insight into how individual atoms interact or metrics like fidelity and entanglement entropy, which impact our results. For this reason, it is useful to compare our results from the physical experiment to those of our simulation on a supercomputer, in which we can track the final and initial energy of individual atoms …

Application Of A Diatomic Molecule Model Potential To A Series Of Homo- And Heterodiatomic Molecules, Dorien E. Carpenter, Javier E. Hasbun

Georgia Journal of Science

We apply a one-dimensional classical model of a diatomic molecule model potential with modifications to H₂, HF, LiF, N₂, and CO. We obtain the unknown parameters of this model by digitizing plots of the potential curves for the molecules from a published, Hartree-Fock based theoretical electron correlation calculation (Piris 2017). We then apply the method of successive approximations to the model in order to calculate the wavenumber for each molecule in the series. The wavenumber depends on a parameter which in turn depends on the initial conditions. The value of this parameter for each individual molecule …

Size Effect On The Optical Response Of Cylindrical Palladium Nanoparticles, Salem Marhaba, Mohammed Khalaf

BAU Journal - Science and Technology

In this work, a computational study is carried out to investigate the optical response of palladium nano-cylinders. The Finite Element Method (FEM) is employed using the COMSOL MULTIPHYSICS simulation program to calculate the scattering, absorption, and extinction cross-sections. The influence of the size of the cylindrical nanoparticles on their optical properties is discussed. The results are plotted for a broad spectral range of wavelengths from ultra-violet to infra-red of the incident electromagnetic wave on the cylindrical nanoparticles.

Intrinsic Point Defects (Vacancies And Antisites) In Cdgep2 Crystals, Timothy D. Gustafson, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, Kent L. Averett, Jonathan E. Slagle, Larry E. Halliburton

Faculty Publications

Cadmium germanium diphosphide (CdGeP₂) crystals, with versatile terahertz-generating properties, belong to the chalcopyrite family of nonlinear optical materials. Other widely investigated members of this family are ZnGeP₂ and CdSiP₂. The room-temperature absorption edge of CdGeP₂ is near 1.72 eV (720 nm). Cadmium vacancies, phosphorous vacancies, and germanium-on-cadmium antisites are present in as-grown CdGeP₂ crystals. These unintentional intrinsic point defects are best studied below room temperature with electron paramagnetic resonance (EPR) and optical absorption. Prior to exposure to light, the defects are in charge states that have no unpaired spins. Illuminating a CdGeP_{2 …}

A Monte-Carlo Simulation Of Gamma Rays In A Sodium Iodide Detector, Ben Kessler

Physics

Gamma rays principally interact with matter through Compton scattering, photoelectric effect, pair production, and triplet production. The focus of this simulation is to study the theoretical energy spectrum created by gamma rays from a Cesium-137 source, which produces gamma photons with an energy of 0.662 MeV. At this energy level, most interactions are results of Compton scatters and the photoelectric effect. Therefore, this simulation only models those two effects on gamma rays. Using Monte Carlo methods and the Metropolis algorithm to sample the probability distributions of the two effects allowed for the simulation of gamma rays in a Sodium Iodide …

Design Modular Command And Data Handling Subsystem Hardware Architectures, Abdullah Alsalmani

Theses

Over the past few years, On-Board Computing Systems for satellites have been facing a limited level of modularity. Modularity is the ability to reuse and reconstruct the system from a set of predesigned units, with minimal additional engineering effort. CDHS hardware systems currently available have a limited ability to scale with mission needs. This thesis addresses the integration of smaller form factor CDHS modules used for nanosatellites with the larger counterparts that are used for larger missions. In particular, the thesis discusses the interfacing between Modular Computer Systems based on Open Standard commonly used in large spacecrafts and PC/104 used …

Non-Degenerate Two-Photon Absorption And Excited State Line Shapes In Alkali Vapors, Timothy M. True

Theses and Dissertations

The rubidium 5S-5D two-photon transitions were probed between 758-798 nm, where a six order of magnitude change in the cross section was observed and the polarization dependence was seen explicitly. Collisional rates are measured in cesium on the 6P-9S and 5D-10F transitions, with broadening rates as large as 710 MHz/Torr and shifting rates as large as 273 MHz/Torr. We observe Stark broadening on the cesium 5D-10F line shape, with Lorentzian width increasing from 200 MHz to 40 GHz. The influence of electron impact is discussed under these conditions and with 0-20 Torr of helium. Cascade amplified spontaneous emission is seen …

Filaments And Their Application To Air Lasing, Spectroscopy, And Guided Discharge, Ali Rastegari

Optical Science and Engineering ETDs

Laser filamentation is a fascinating phenomenon that occurs when an intense laser beam travels through transparent materials, in particular air. At sufficiently high power (TW in the near IR, GW in the UV), instead of spreading out like a regular laser beam, something remarkable happens: the laser beam becomes tightly focused, creating a thin and intense column of light called a laser filament. Laser filamentation is characterized by two main properties: (I) a high-intensity core that remains narrow over long distances beyond the Rayleigh range and (II) a low-density plasma channel within the core. In recent years, laser filamentation has …

Effective Non-Hermiticity And Topology In Markovian Quadratic Bosonic Dynamics, Vincent Paul Flynn

Dartmouth College Ph.D Dissertations

Recently, there has been an explosion of interest in re-imagining many-body quantum phenomena beyond equilibrium. One such effort has extended the symmetry-protected topological (SPT) phase classification of non-interacting fermions to driven and dissipative settings, uncovering novel topological phenomena that are not known to exist in equilibrium which may have wide-ranging applications in quantum science. Similar physics in non-interacting bosonic systems has remained elusive. Even at equilibrium, an "effective non-Hermiticity" intrinsic to bosonic Hamiltonians poses theoretical challenges. While this non-Hermiticity has been acknowledged, its implications have not been explored in-depth. Beyond this dynamical peculiarity, major roadblocks have arisen in the search …

Photophysical And Photochemical Processes In Small Molecules And Materials For Solar Energy Conversion, Ethan Lambert

Honors Theses

The work covered in this thesis all falls under the theme of photophysical processes after light and matter interact. Those of primary interest are Raman scattering induced vibrations and excited state dynamics probed by transient absorption spectroscopy. Small molecules are studied with Raman spectroscopy and computational chemistry. These studies unearth the shifts in vibrational frequency as a function of charge transfer or receipt and how a quantitative assay of natural orbital populations and delocalization can offer both the nature and magnitude of this charge transfer. Further, a method is presented that builds upon previous work within the academic family tree; …

Exploring The Interaction Of Minor-Groove-Binder Netropsin With Dna Using Optical Tweezers, Irbazhusain Shaikh

Honors Program Theses and Projects

Netropsin is an antibiotic that binds in the minor grooves of DNA, which also exhibits anticancer properties. There have been many previous studies that explored the binding of this drug to DNA using traditional methods where an ensemble averaging is used. In this study we explore the interaction of Netropsin with DNA at a single molecule level using dual beam optical tweezers. We trapped and stretched a single DNA molecule using optical tweezers to measure the force experienced by the DNA as a function of extension in the absence and presence of various concentrations of Netropsin. Our results show the …

Domain Wall Saddle Point Morphology In Ferroelectric Triglycine Sulfate, C. J. Mccluskey, A. Kumar, Alexei Gruverman, I. Luk’Yanchuk, J. M. Gregg

Alexei Gruverman Publications

Ferroelectric domain walls, across which there is a divergence in polarization, usually have enhanced electrical conductivity relative to bulk. However, in lead germanate, head-to-head and tail-to-tail walls are electrically insulating. Recent studies have shown that this is because, when oppositely oriented domains meet, polar divergence is obviated by a combination of domain bifurcation and suspected local dipolar rotation. To explore the uniqueness, or otherwise, of this microstructure, we have used tomographic piezoresponse force microscopy to map three-dimensional domain morphologies in another uniaxial ferroelectric system: triglycine sulfate. This mapping reveals an abundance of domain wall saddle points, which are characteristic of …

Spectra Of Atmospheric And Astronomical Molecules, W. D. Cameron

Physics Theses & Dissertations

Spectroscopy techniques are focused on spectra of molecules of interest to the Earth’s atmosphere and/or astronomy and astrophysics. Laboratory spectroscopy as well as remote satellite sensing are applied. Using the Fourier transform spectrometer aboard the Atmospheric Chemistry Experiment (ACE) satellite to measure the absorption spectra of the Earth’s atmosphere through solar occultation limb observation demonstrates that volcanic eruption plumes can be located and tracked through their SO₂ content. The presence of those plumes is corroborated by overlaying infrared atmospheric aerosol extinction observed by the 1 μm imager on the same satellite. Tracking atmospheric aerosol movement with the ACE …

Apparatus And Instrumentation Design For Investigation Of Surface Impact Effects On Superconductivity, Austin Back

All Theses

The effects of ion irradiation on the physical properties of materials make EBITs an invaluable tool for many scientific and engineering fields. Many experiments rely on the use of these lab setups to test for device reliability, explore surface physics phenomena, and replicate the environment for many physical systems that are not readily accessible. We seek to extend the capabilities of these experiments using the CUEBIT and a new sample holder installed in section 3.

This thesis begins by presenting an overview of the CUEBIT and the basic operations of the equipment. This is followed by a brief explanation of …

Study Of Missing Mass Background In The Clas12 Detector, Jessie Hess, Gerard P. Gilfoyle, Lamya Baashen

Honors Theses

At Jefferson Lab we use the CLAS12 detector to measure the neutron magnetic form factor. An accurate measurement of the CLAS12 neutron detection efficiency (NDE) is required. We use the nuclear reaction ���� → ��′��+�� as a source of tagged neutrons and obtain the NDE from the ratio of expected neutrons to detected ones. We assume the final state consists of ��′��+�� only, use the ��′��+ information to predict the neutron's position(expected) and then search for that neutron(detected). We select neutrons with the missing mass (MM) technique. We use simulation to validate our methods. We simulated events with the Monte-Carlo …

Electron Charge To Mass Ratio, Tori Freeman, Quinlin Reynolds

ATU Scholars Symposium

The purpose of this experiment is to confirm the e/m ratio and charge of an electron discovered initially by J.J. Thomson. We use an electron beam generated inside an e/m tube and Helmholtz coils that generate a magnetic field which deflects the path of the electrons. The radius of the path can be measured and from there the magnitude of the magnetic field and the charge-to-mass ratio can be found. This experiment was successful in confirming the results found by J.J. Thomson and his cathode ray experiments. The results of this experiment had a 0.5% error with the accepted e/m …

Process Of Building And Designing A Spectrometer, Tori Freeman

ATU Scholars Symposium

Spectroscopy is the study and measurement of electromagnetic spectra resulting from electromagnetic radiation interacting with matter. Each element when excited emits a unique spectrum containing light of various wavelengths. The identity of the element can then be determined by examining the spectra. A spectrometer is a scientific instrument that utilizes optics, mirrors, and lenses to capture and examine spectra. A classroom spectrometer is potentially useful in the demonstration of numerous physics principles such as diffraction, reflection, ray optics, etc.

Keywords: Spectrometry, optics, spectrum

Femtotesla Magnetometry And Nanoscale Imaging With Color Centers In Diamond, Yaser Silani

Optical Science and Engineering ETDs

Intriguing photophysical properties of color centers in diamond make them ideal candidates for many applications from imaging and sensing to quantum networking. In the first part of this work, we have studied the silicon vacancy (SiV) centers in diamond for nanoscale imaging applications. We showed that these centers are promising fluorophores for Stimulated Emission Depletion (STED) microscopy, owing to their photostable, near-infrared emission and favorable photophysical properties. In the second part, we built a femtotesla Radio-Frequency (RF) magnetometer based on the diamond nitrogen vacancy (NV) centers and magnetic flux concentrators. We used this sensor to remotely detect Nuclear Quadrupole Resonance …

Analog Cosmology And Superfluidity In Atomic Gases And Electronic Materials, Anshuman Bhardwaj

LSU Doctoral Dissertations

We present a study of analog cosmological models in Bose-Einstein condensates (BEC) and in graphene, and superfluidity in a box-shaped traps. We start by examining the dynamics of a Bose-Einstein condensate (BEC) trapped inside an expanding toroid that can realize an analog inflationary universe. The expanding condensate forces phonons to undergo redshift and damping due to quantum pressure, owing to the thinness of the ring. We predict that such expanding BECs can exhibit spontaneous phonon creation from the vacuum state and show how it would manifest in the atom density and density correlations and discuss connections with the inflationary theory. …

Diffractive Imaging Of Laser Induced Molecular Reactions With Kiloelectron–Volt Ultrafast Electron Diffraction, Yanwei Xiong

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Capturing the structural changes during a molecular reaction with ultrafast electron diffraction (UED) requires a high spatiotemporal resolution and sufficiently high signal-to-noise to record the signals with high fidelity. In this dissertation, I have focused on the development of a tabletop gas phase keV-UED setup with a femtosecond temporal resolution. A DC electron gun was employed to generate electron pulses with a high repetition rate of 5 kHz. The space charge effect in the electron pulse was ameliorated by compressing the 90 keV electron pulse longitudinally with a time varying electric field in an RF cavity. The velocity mismatch between …

New Far-Infrared Laser Frequencies Generated By Ch3cn, Cd3cn, 13ch3i, Cd3i, And 13cd3i, Michael Jackson

All Faculty Scholarship for the College of the Sciences

Heterodyne techniques have been used to experimentally determine, for the first time, the frequencies for nineteen laser emissions ranging from 264 to 984 GHz. These laser emissions were generated by optically pumping either CH₃CN, CD₃CN, ¹³CH₃, CD₃I, or ¹³CD₃I with a CO₂ laser. This includes the newly discovered 566.325-μ m laser emission from optically pumped ¹³CD₃I. The fractional uncertainties with which these frequencies were experimentally determined, up to ± 5 × 10^− 7, were of sufficient accuracy to confirm or revise …

The Quantitative Microanalysis Explorer: Introducing Web-Based Visualization For Optical, Electron, And Quantitative X-Ray Maps For Studying Lunar Samples, Angelina Minocha

Senior Honors Papers / Undergraduate Theses

Modern sample imaging techniques produce data in the form of large mosaics, wherein every pixel contains valuable mineralogical information. These heavy data files are challenging for most computers to load and process, furthermore access to lunar and other extraterrestrial samples is limited. We developed the QME Tool to display optical, electron, and quantitative x-ray maps in conjunction with one another to overcome these challenges and advance mineralogy data presentation and analysis. The images and quantitative data was collected using specialized techniques, followed by an extensive image co-registration process. The interface was developed using OpenSeadragon, “An open-source, web-based viewer for high-resolution …

Characterizing Gesn Alloys By Sem/Eds And Photoluminescence Spectroscopy, Christopher M. Sutphin

Theses and Dissertations

Germanium tin (GeSn) alloys are being studied as potential transition metal (Group IV) photoelectric semiconductors or optical detectors. GeSn alloys could be employed as an optically active material within a computer. Compared to current technologies, a direct band gap GeSn alloy can be engineered to operate with higher thermal stability and efficiency. The GeSn alloy studied was composed of Ge and Si substrates with various Sn percentages grown using remote plasma-enhanced chemical vapor deposition (RPECVD). Photoluminescence spectroscopy (PL) techniques were initially used to determine the GeSn properties, including the band gap. The Ge_91.2Sn_8.8 PL spectra suggested the …

Description Of Reaction And Vibrational Energetics Of Co2-Nh3interaction Using Quantum Computing Algorithms, Manh Tien Nguyen, Yueh-Lin Lee, Dominic Alfonso, Qing Shao, Yuhua Duan

Markey Cancer Center Faculty Publications

CO2 capture is critical to solving global warming. Amine-based solvents are extensively used to chemically absorb CO2. Thus, it is crucial to study the chemical absorption of CO2 by amine-based solvents to better understand and optimize CO2 capture processes. Here, we use quantum computing algorithms to quantify molecular vibrational energies and reaction pathways between CO2 and a simplified amine-based solvent model—NH3. Molecular vibrational properties are important to understanding kinetics of reactions. However, the molecule size correlates with the strength of anharmonicity effect on vibrational properties, which can be challenging to address using classical computing. Quantum computing can help enhance molecular …