Atomic, Molecular and Optical Physics Commons^™

Calculating Potential Energy Curves Of Molecular Hydrogen And Its Ion Using Psi4 For Blinc Fusion Applications*, Angelina Castillo, Oscar Coral, Canaan Hercules, Blake Laing, Vola Andrianarijaona

Campus Research Month

Southern Adventist University’s Beamline for Ionic and Neutral Collisions (BLINC) is investigating the interactions between hydrogen molecules and fusion particles. To perform in-house theoretical calculations, the BLINC Theory and Analysis Group is testing Psi4 as a viable computational method for BLINC fusion research. Successful calculations of the potential energy curves and dissociation energies of H₂ and H₂⁺ have been completed and compared to known values. Preliminary results align with known values, demonstrating Psi4’s potential for BLINC research. Future work will focus on the vibrational energies, wavefunctions, and transition probabilities of H₂ and H₂⁺.

Construction Of Alkali Oven For Charge Transfer Collisions In Beamline Applications*, Benjamin D. Chun, Oscar T. Coral, Gabriella Kim, Naomi Munyaka, Vola Andrianarijaona

Campus Research Month

This work presents the desig and development of an alkali metal oven used for charge-transfer collision experiments within the Beamline for Ionic and Neutral Collisions (BLINC) at Southern Adventist University. This oven is engineered to produce a stable and controllable alkali vapor source (K/Cs), enabling interactions between the H2+ ions and neutral alkali atoms for the study of rovibrational energy transfer.

The alkali metal oven was designed to be modular to switch out different capillary designs for diverse vapor release into the beamline. This system was designed using SolidWorks and fabricated through CNC machining, with particular emphasis on thermal wiring …

Exclusive Neutral Pion Electroproduction Cross Section Measurements With A Neutral Particle Spectrometer, Mitchell R. Kerver

Physics Theses & Dissertations

Deep Virtual Compton Scattering (DVCS), the exclusive electron-proton scattering process ep →e′p′γ, provides access to generalized parton distributions (GPDs), which correlate informa tion about the longitudinal momentum and transverse spatial structure of quarks inside the nucleon. Experiment E12-13-010 in Hall C at Jefferson Lab was designed to take high-precision measure ments of the DVCS cross section over an extended kinematic range using the newly commis sioned Neutral Particle Spectrometer (NPS). The NPS features a high-resolution electromagnetic calorimeter and a streaming data acquisition system optimized for operation at high luminosities. This thesis presents the detector and analysis work carried out to …

Investigation Of Molecular Footprints In Ultra-High Diluted Homoeopathic Solutions Of Arnica Montana And Rhus Toxicodendron Through Combined Infrared And Impedance Spectroscopy, Sharbadeb Kundu, Usha Rani Dash, Chirasree Roychaudhuri, Aindrila Roy, Sanatan Chattopadhyay, Rathin Chakravarty, Debadatta Nayak, Subhash Kaushik, Amit Roy Chowdhury, Ananya Barui, Subhadip Chakraborty

Indian Journal of Research in Homoeopathy

Background: The study of ultra-high diluted (UHD) solutions is a compelling and controversial domain in modern science. Despite numerous investigations and hypotheses, there is a lack of rigorous, reproducible empirical evidence supporting the existence of molecular footprints beyond the Avogadro's limit. Objective: This study conducted a detailed investigation of the molecular and electrical properties, focusing on hydrogen bonding and impedance to understand the fundamental nature of UHD solutions. Materials and methods: Combined impedance and infrared spectroscopic investigations were performed to probe the structural behaviour of relevant water networks at the molecular level of UHD alcoholic extract of Arnica montana (AM) …

Guiding Fast Ion Beam By Suppressing Secondary Ions, Yingli Xue, Junliang Liu, Mingwu Zhang, Daniel Fischer, Guoxing Xia, Nikolaus Stolterfoht, Reinhold Schuch, Yehong Wu, Bian Yang, Xiaoxiao Li, Caojie Shao, Wei Wang, Zhangyong Song, Xing Fang

Physics Faculty Research & Creative Works

We demonstrate that secondary ions sputtered from a macrocapillary's inner surface by the primary beam induce premature saturation of the guiding field, hindering fast ion guiding. By suppressing secondary ion sputtering with grooved surfaces, we achieve a guiding-field potential difference exceeding 1 kV, 2 orders of magnitude larger than previously achieved in stable ion guiding. This enables stable guiding of a 20-keV/q O5+ beam at offset angles up to 15°, with transmitted ions retaining their initial energy and charge state. A self-consistent field model accurately reproduces these results, revealing that guiding performance relies on managing secondary ions and the channel's …

Uranium Chemical Compound Classification Using Sub-Images And Statistical Machine Learning For Nuclear Forensics, Lee C. Lambert, Brett J. Borghetti, Abigail A. Bickley

Faculty Publications

Uranium particle analysis from Scanning Electron Microscope (SEM) imagery is a crucial tool in nuclear forensics. The particle morphology lexicon proposed by Tamasi et al. in J Radioanal Nucl Chem 307, 1611–1619 (2016) follows a standardized, manual identification process to identify particle morphology features. The present work seeks to mirror this methodology using computer feature selection from the scikit-image Python library rather than human classification. Using a random forest classifier, a 56% overall uranium true positive classification accuracy (a 39.6% balanced classification accuracy) was achieved on a test set outperforming a naïve (chance) model by 48%. The methodology introduced splits …

Proposed Methodology For Correcting Fourier-Transform Infrared Spectroscopy Field-Of-View Scene-Change Artifacts, Kody A. Wilson, Michael L. Dexter, Benjamin F. Akers, Anthony L. Franz

Faculty Publications

Fourier-transform spectrometers are widely used for spectral measurements. Changes in the field of view during measurement introduce oscillations into the measured spectra known as scene-change artifacts. Field-of-view changes also introduce uncertainty about which target the measured spectrum represents. Though scene-change artifacts are often present in dynamic data, their significance is disputed in the current literature. This work presents a theoretical framework and experimental validation for scene-change artifacts. Field-of-view changes introduce variable interferogram offsets, which standard processing techniques assume are constant. The error between the interferogram offset and its estimate is Fourier-transformed, yielding scene-change artifacts, often confused with noise, in the …

A Comparison Of Modeled Daytime E Regions From E-Probed And Pyiri With Ionosonde Observations, Daniel J. Emmons, Cornelius C. J. H. Salinas, Dong L. Wu, Nimalan Swarnalingam, Eugene V. Dao, Jorge L. Chau, Yosuke Yamazaki, Kyle E. Fitch, Victoriya V. Forsythe

Faculty Publications

While the F region is the primary focus of many ionospheric models because it contains the peak electron density, the E region is an important region for ionospheric conductivities and high-frequency radio propagation. This study analyzes modeled E regions from the newly developed PyIRI and E-PROBED models. A long-term comparison of E region predictions from E-PROBED and PyIRI with ionosonde observations is performed for three sites spanning low- (Fortaleza, Brazil), mid- (El Arenosillo, Spain), and high-latitudes (Gakona, Alaska). Modeled foE and hmE trends are compared against a combination of manually-scaled and automatically-scaled ionograms using ARTIST-5 for the period 2009–2024 for …

Frequency Stabilization Of An Affordable Adjustable Repetition Rate Dual Frequency Comb Spectrometer, Michael Moran

Physics, Astronomy and Geophysics Honors Papers

Two affordably home-built optical frequency combs are stabilized for use in molecular spectroscopy. Each comb is paired with a multi-tiered stabilization scheme that will enable the dual-comb spectrometer to perform precision measurements. The two degrees of freedom for an optical frequency comb, the repetition rate frequency and offset frequency, are accounted for in this stabilization scheme. The repetition rate is directly stabilized through control of the laser enclosure temperature and the fiber laser cavity length. The offset frequency is controlled indirectly via the stabilization of an optical beat note, the heterodyned signal resulting from a narrow linewidth laser and the …

Three-Photon Rydberg Eit Lineshape Analysis In Rubidium, Jackson Lake

Honors Theses

Electromagnetically Induced Transparency detection of high-lying Rydberg states in room-temperature rubidium vapor was investigated using a four state ladder-type excitation scheme with light provided by three External Cavity Diode Lasers (ECDLs) at 780 nm, 776 nm, and 1266 nm. This detection technique was studied by characterizing the lineshape parameters of the EIT transmission peak, specifically the height, width and area of the transparency window as functions of the dressing and coupling laser powers. With the goal of characterizing the linewidth of the transmission signal, a confocal etalon was built and implemented in the optical setup to perform frequency calibration of …

Analyzing Rydberg Atoms Of Rubidium At Room Temperature: Applying Electromagnetically Induced Transparency, Bridger Stiles

Honors Theses

This thesis describes an experimental exploration of electromagnetically induced transparency (EIT) in atoms of 85Rb using a new MOGLabs external cavity diode laser. A two-step ladder technique of EIT was applied using a 5S_1/2→5P_3/2 probe transition and 5P_3/2→nD_5/2 coupling transitions. Significant apparatus tuning was done, including developing a reliable procedure of regulating frequency and scanning the coupling laser over a sufficient mode-hop free range. A Doppler-reduced technique was applied by counter-propagating the probe and coupling beams through the Rb vapor cell. EIT signals were collected at various probe and coupling laser powers to analyze changes in signal size and linewidth. …

Real-Space Imaging Of The Electron-Pair Density Hole In Molecular Auger-Meitner Decay, Mats Simmermacher, Nathan Goff, Andres Moreno Carrascosa, Elke Fasshauer, Thomas Northey, Lingyu Ma, Haiwang Yong, Brian Stankus, Asami Odate, Xuan Xu, Wenpeng Du, Kyle Acheson, Joseph C. Cooper, Daniel Ratner, Mengning Liang, Ruaridh Forbes, Michael P. Minitti, Adam Kirrander, Peter M. Weber

Physics Faculty Publications

Electrons in matter can rearrange extremely quickly under external perturbations, underpinning subsequent structural and chemical transformations. Coulomb interactions between neighbouring electrons often shape this response, giving rise to correlated motion and strongly affecting the distribution of electrons in the system. Here we show that non-resonant hard X-ray scattering can directly access changes in the radial electron-pair density during the rapid rearrangement of core and valence electrons. We do this by studying sulfur hexafluoride molecules undergoing Auger–Meitner decay. We exploit a second-order interaction between the X-ray photons and the molecules to trigger and probe the decay dynamics with a single pulse, …

Non-Gaussian Phenomena In Light Scattering And Applications, Shubham Atul Dawda

Graduate Studies Theses and Dissertations 2026

Physical reality is rarely deterministic; which, when probed by electromagnetic fields that also fluctuate, leads to observables that are most efficiently modelled as statistical processes. At equilibrium, this is usually achieved by invoking the Gaussian statistics of underlying physical processes, however, in practice, one often encounters out-of-equilibrium conditions where Gaussian descriptions may not suffice. Such situations are plentiful in nature– from biology to astronomy. This dissertation addresses several non-Gaussian phenomena associated with light scattering, and includes specific models’ derivations, experimental techniques developments, and demonstrations of potential applications. The systematic presentation will consider circumstances that infringe upon specific assumptions of the …

Investigation Of Exotic Phenomena In Topological Quantum Materials, Iftakhar Bin Elius

Graduate Studies Theses and Dissertations 2026

he First Quantum Revolution established quantum mechanics as the foundation of modern physics, enabling transformative technologies such as semiconductors, lasers, and transistors through prin-ciples of quantization, wave-particle duality, and uncertainty. The ongoing Second Quantum Rev-olution harnesses entanglement, superposition, and coherence to advance quantum computation, communication, simulation, and sensing. Central to this endeavor is the study of quantum mate-rials hosting novel electronic structures and emergent phases, including topological insulators and Dirac, Weyl, and nodal-line semimetals. In this thesis, using angle-resolved photoemission spec-troscopy (ARPES), transport measurements, and density functional theory (DFT) calculations, we investigate three classes of materials: (i) magnetic topological semimetals, …

A Theoretical Study Of Molecular Photoionization: Applications To Molecules Of Astrophysical And Atmospheric Interest, Conner Penson

Graduate Studies Theses and Dissertations 2026

This thesis is devoted to the development of the model for total molecular photoionization spectra which is general to diatomic molecules and the application of this model to two benchmark systems, CH and N2, for verification. This model combines multi-channel quantum defect theory, first-principles ab initio molecular calculations, and vibrational frame transformation to accurately model molecular photoionization and electron impact including vibrational dynamics. The scattering data and transition dipole moments for the molecular systems were calculated using R-matrix method through the UKRMol+ codes. A vibrational frame transformation is then performed and multi-channel quantum defect theory is used to calculate closed …

Shock-Wave Structure In A Monatomic Gas Mixture With Rydberg Atoms, Anna Markhotok

Physics Faculty Publications

The effect of atom size on the shock-wave structure in a binary monatomic gas mixture with Rydberg atoms has been investigated. The problem was solved numerically using the system of hydrodynamic equations in argon gas for the atom-size ratios between 2 and 100, T = 1500 K, and the density between 10¹⁷ and 10²⁰ m−³. It was found that the presence of larger-sized atoms in the mixture results in shock front splitting that is on the order of the mean free path for this component. The results could be of interest in supersonic plasma dynamics and in astrophysics, studying shock …

Real-Space Imaging Of The Electron-Pair Density Hole In Molecular Auger-Meitner Decay, Mats Simmermacher, Nathan Goff, Andres Moreno Carrascosa, Elke Fasshauer, Thomas Northey, Lingyu Ma, Haiwang Yong, Brian Stankus, Asami Odate, Xuan Xu, Wenping Du, Kyle Acheson, Joseph C. Cooper, Daniel Ratner, Mengning Liang, Ruaridh Forbes, Michael P. Minitti, Adam Kirrander, Peter M. Weber

Physics Faculty Publications

Electrons in matter can rearrange extremely quickly under external perturbations, underpinning subsequent structural and chemical transformations. Coulomb interactions between neighbouring electrons often shape this response, giving rise to correlated motion and strongly affecting the distribution of electrons in the system. Here we show that non-resonant hard X-ray scattering can directly access changes in the radial electron-pair density during the rapid rearrangement of core and valence electrons. We do this by studying sulfur hexafluoride molecules undergoing Auger–Meitner decay. We exploit a second-order interaction between the X-ray photons and the molecules to trigger and probe the decay dynamics with a single pulse, …

Quantum Monte Carlo Calculations Of Zemach Moments In A ≤ 9 Nuclei, Garrett B. King, Sonia Bacca, Graham Chambers-Wall, Alex Gnech, Saori Pastore, Maria Piarulli, R. B. Wiringa

Physics Faculty Publications

Modern atomic spectroscopy has reached a level of precision at which nuclear-structure effects can no longer be neglected and must be quantified reliably. In particular, hyperfine splittings depend on the Zemach radius, which encodes the convolution of the nuclear charge and magnetization distributions. The third electric Zemach moment provides a related finite-size measure and enters the elastic two-photon-exchange contribution to the Lamb shift in muonic atoms. Here, we compute Zemach radii and other electromagnetic moments for light nuclei using quantum Monte Carlo techniques within modern ab initio nuclear theory. Using Norfolk two- and three-body interactions derived within chiral effective field …

First Remi Experiments At A Cryogenic Ion Storage Ring, M. Schulz, F. Herrmann, W. Zhang, A. Dorn, M. Grieser, F. Grussie, H. Kreckel, O. Novotny, A. Wolf, T. Pfeifer, C. D. Schröter, R. Moshammer

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

We have recorded double, triple, and quadruple coincidences between neutralized projectiles, recoiling target ions, and two electrons created in collisions of slow anions with neutral atoms. The experiments were performed at the cryogenic storage ring in Heidelberg. The recoil ions and ejected electrons were momentum-analyzed using a Reaction Microscope (ReMi) spectrometer. Various processes involving electron detachment from the projectile accompanied by various transitions in the target were investigated. Detachment without any transition in the target is qualitatively well described by a quasi-free electron model in the case of an Ar target. In detachment with single target ionization, no signatures of …

Design, Fabrication Modeling, And Optical Metrology Of Mwir Silicon Metalenses, Weiyu Chen

Graduate Studies Theses and Dissertations 2026

Mid-wave infrared (MWIR) optical systems require compact, broadband, manufacturable components whose performance can be predicted and measured reliably. Silicon metalenses are attractive because silicon combines high refractive index, MWIR transparency, and semiconductor-compatible fabrication. This dissertation develops a scale-bridging design–fabrication-modeling–metrology framework for MWIR silicon metalenses.

A shared full-aperture framework connects meta-atom libraries, physical layout generation, angular-spectrum propagation, point-spread-function calculation, and focal-plane energy metrics. Building on this foundation, the Dispersive Sweatt Model (DSM) incorporates meta-atom dispersion into conventional ray-tracing software, enabling broadband co-optimization of metasurfaces and refractive elements. A process-aware design framework then incorporates scanning electron microscopy (SEM)-measured height–radius relationships produced by …

Fully Differential Studies On Dissociative Capture In P + D2 Collisions And On Ionization In P + He Collisions, Shruti Majumdar

Doctoral Dissertations

Advancing our understanding of few-body dynamics in simple atomic systems is a fundamental objective in atomic scattering research. The underlying problem is that the Schrödinger equation is not analytically solvable for more than two mutually interacting particles. This involves a comprehensive exploration of various channels, such as ionization, capture, and excitation. A common theoretical approach to describe ion-atom collisions is based on perturbation theory, where the scattering amplitude is expanded in powers of the interaction potential. Here, understanding the few-body problem means accurately describing the relative importance of the higher- vs the first order terms.

In the case of ionization, …

Characterizing A Delay-Programmable Two-Color Femtosecond Light Source For Coherent Control Of Atomic Multi-Photon Ionization Processes, Mason Tanner Toombs

Masters Theses

"In this work a delay-programmable two-color femtosecond laser based on a chirped-seed noncollinear optical parametric amplifier was characterized. This design utilizes a titanium-sapphire crystal oscillator to generate broadband pulses of light spanning approximately 600-1200 nm, with a pulse duration of ~5 fs, repetition rate of 80 MHz, and pulse energy of ~2.5 nJ. An infrared portion of the light, spanning approximately 1020-1060 nm, is split off from the pulse and used to generate a pump beam. By dispersing the remaining seed beam and controlling the relative timing delay between the seed and the pump, tunable frequencies within the seed can …

Rydberg Atom Arrays For Electric Field Sensing, James P. Hamilton

Honors College Theses

Rydberg atoms, hydrogen-like atoms that can be excited to states of high principal quantum number that carry correspondingly large electric dipole moments, have become leading candidates for precision electric field sensing. Arrays of such atoms, each trapped in a focused laser beam called an “optical tweezer,” are a particularly promising platform, since the strong dipole-dipole interactions between neighboring atoms provide a resource unavailable in a single-atom sensor. This thesis develops a theoretical and numerical framework for electric field measurement in small Rydberg atom arrays. We begin with a two-level model of a single atom, derive the Hamiltonian and equations of …

An Application Of Molecular Dynamics To Hed Plasma Physics: Point And Group Defect Diffusion In Coulomb Crystals, Levi Webb

Theses and Dissertations

Molecular dynamics (MD) simulations are used to explore the microscopic behaviors of complex systems that cannot be easily studied experimentally. In particular, the microphysics of high energy density (HED) astrophysical plasma environments remain inaccessible by modern experiment---even in laser facilities, these plasmas exist only on short timescales that do not lend easily to investigation. The diffusion of point and group defects through crystallized plasmas in the cores of white dwarfs and neutron star crusts, called Coulomb crystals, has potentially macroscopic implications for the evolution of these bodies. Thus, I employ the widely-used MD code LAMMPS to simulate small Coulomb crystal …

First-Principles Investigation Of Quasi-One-Dimensional Van Der Waals Magnets For Advancing Low-Dimensional Spintronics, Alyssa Horne

Dissertations, Master's Theses and Master's Reports

Van der Waals (vdW) magnets have been of great interest for advancing low- dimensional spintronics. A notable example is the quasi-one-dimensional (Q1D) vdW CrSbSe₃, as it is composed of individual one-dimensional units that are held together by the vdW forces. Finding other Q1D vdW magnets that exhibit non-metallic behavior together with long range ferromagnetic ordering is critical in developing next generation spintronics. Here in, using first-principles density functional theory (DFT), we investigate the compositional effects on electronic and magnetic behavior of Cr_1–xMn_xSbSe₃ (x = 0, 0.5, 1). When 50% of Cr is replaced …

Nanostructured Cathode Catalysts For Aem Electrolysis: From Catalyst Design To Degradation And Hydrogen Dynamics, Yamini Kumaran

Electronic Theses & Dissertations (2024 - present)

Anion exchange membrane water electrolysis (AEMWE) presents a promising pathway toward cost-effective and sustainable hydrogen production by integrating the chemical robustness of alkaline systems with the compact, zero-gap design of proton exchange membrane electrolyzers. However, the widespread implementation of AEMWE is limited by the availability of highly active and durable platinum-group-metal (PGM)-free catalysts and by an incomplete understanding of their degradation behavior under realistic operating conditions.

This dissertation focuses on the development, characterization, and mechanistic investigation of nanostructured MoNi₄–MoO₂-based electrodes for efficient and stable hydrogen generation under alkaline and membrane-integrated environments. MoNi₄–MoO₂ nanorods …

Retrieval And Characterization Of Aerosol Optical And Microphysical Properties Following Pyrocumulonimbus Events From Sageiii/Iss, Vishal G. Bagadia

Electronic Theses & Dissertations (2024 - present)

Stratospheric aerosols play an important role in maintaining global radiative balance with impacts to stratospheric equilibria through physical and chemical forcings.  Stratospheric aerosol size distributions, in particular aerosol size, are vitally important in determining the physical and chemical impacts of aerosols in the stratosphere. The representation of aerosol size and size distributions in most climate models contain large uncertainties due to relatively sparse sampling of stratospheric aerosols. Occultation measurements from satellite provide an unique opportunity to retrieve the aerosol size distribution using high quality aerosol extinction measurements. A retrieval algorithm is developed to characterize size distributions of stratospheric aerosols from …