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Articles 1 - 30 of 944
Full-Text Articles in Physical Chemistry
Synthesis And Charge Transport Characterization Of 9,9'-Bifluorenylidene-Based Conjugated Molecules For Single-Molecule Conductance, Zach Moughamian, Jahnavi Badiganti, Jinjia Xu
Synthesis And Charge Transport Characterization Of 9,9'-Bifluorenylidene-Based Conjugated Molecules For Single-Molecule Conductance, Zach Moughamian, Jahnavi Badiganti, Jinjia Xu
Undergraduate Research Symposium
Molecular electronics explores the use of individual molecules as functional components in nanoscale electronic devices. In this project, fluorenone-based π-conjugated molecules including 9,9'-bifluorenylidene-S and triphenylamine-substituted derivatives were synthesized to investigate structure-property relationships relevant to molecular charge transport. The synthesized compounds were obtained in 13% and 27% yield respectively. ¹H NMR spectroscopy confirms characteristic aromatic resonances in the 7-9 ppm region consistent with the conjugated framework. UV–Vis spectroscopy reveals absorption maxima at 459 nm and 470 nm, indicating extended π-conjugation and donor-acceptor effects. Single-crystal X-ray diffraction confirms the structure of 9,9'-bifluorenylidene-S, which crystallizes in the monoclinic system (space group P2₁/c). In …
Fully Anharmonic Infrared Spectra Of Neutral Polycyclic Aromatic Hydrocarbons With Up To 38 Carbons, Nolan J. H. White, Vincent J. Esposito, Christiaan Boersma, Louis J. Allamandola, Jesse D. Bregman, Alexandros Maragkoudakis, Pasquale Temi, Ryan Fortenberry
Fully Anharmonic Infrared Spectra Of Neutral Polycyclic Aromatic Hydrocarbons With Up To 38 Carbons, Nolan J. H. White, Vincent J. Esposito, Christiaan Boersma, Louis J. Allamandola, Jesse D. Bregman, Alexandros Maragkoudakis, Pasquale Temi, Ryan Fortenberry
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Interstellar aromatic infrared band (AIB) spectra show agreement with presently computed anharmonic spectra for various types of polycyclic aromatic hydrocarbons (PAHs) determined using a novel semiempirical quantum chemical method. Since the AIB spectrum is a blend of emission spectra from a vast number of different PAHs, likely with an array of different molecular structures, the spectra for a sample set of 31 PAHs ranging in size from naphthalene (C10H8) up to circumbiphenyl (C38H16) are combined, giving consideration to almost all PAH structural motifs. The computed numerical quartic force fields coupled to second-order …
Infrared Spectroscopy And Photochemistry Of Aromatic Nitriles In Para-Hydrogen Matrices, Sam Mcgrath, Vincent J. Esposito, Linshan Zeng, Thomas H. Speak, Brendan Moore, Pavle Djuricanin, Jun Miyazaki, Takamasa Momose, Ilsa R. Cooke
Infrared Spectroscopy And Photochemistry Of Aromatic Nitriles In Para-Hydrogen Matrices, Sam Mcgrath, Vincent J. Esposito, Linshan Zeng, Thomas H. Speak, Brendan Moore, Pavle Djuricanin, Jun Miyazaki, Takamasa Momose, Ilsa R. Cooke
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Motivated by recent detections of several aromatic nitriles in Taurus Molecular Cloud 1, we report laboratory and theoretical investigations of the vibrational spectroscopy and photochemistry of singly and doubly cyanosubstituted benzene in solid para-hydrogen matrices. We compare the photochemistry of cyanobenzene (benzonitrile) and three dicyanobenzene isomers initiated by excitations at 193 nm. In addition, we report the photochemistry of deuterated cyanobenzene (d5-cyanobenzene), enabling us to determine the major products produced during the cyanobenzene photodissociation. The major products observed in the photolysis of all the nitriles are HCN and HNC, which are likely produced by hydrogen abstraction from para-hydrogen by the …
Photochemistry At The Air-Aerosol Interface, Yi Rao
Photochemistry At The Air-Aerosol Interface, Yi Rao
Funded Research Records
No abstract provided.
Zero-Field Diode Effect As A Constraint On Cuprate Superconductivity Mechanisms, Armen Gulian, Serafim Teknowijoyo, Vahan Nikoghosyan
Zero-Field Diode Effect As A Constraint On Cuprate Superconductivity Mechanisms, Armen Gulian, Serafim Teknowijoyo, Vahan Nikoghosyan
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present measurements demonstrating that copper-oxide high-temperature superconductors can exhibit broken time-reversal symmetry in the absence of external magnetic fields. Using Tl2Ba2CaCu2O8 microbridges, we observe a pronounced superconducting diode effect at 100 K under strictly zero-field conditions. This nonreciprocal response remains unchanged in magnetic fields up to ±100 Oe. Our results are consistent with recent reports of zero-field diode behavior in Bi2Sr2CaCu2O8+𝛿 and together they indicate that time-reversal symmetry breaking may be an intrinsic property of the cuprate superconducting state. These findings provide an additional experimental …
Single Fluorogens And Orientation-Localization Microscopy For Quantifying Chemical And Biomolecular Dynamics At The Nanoscale, Yiyang Chen, Yuanxin Qiu, Matthew D. Lew
Single Fluorogens And Orientation-Localization Microscopy For Quantifying Chemical And Biomolecular Dynamics At The Nanoscale, Yiyang Chen, Yuanxin Qiu, Matthew D. Lew
Electrical & Systems Engineering Publications and Presentations
Many chemical systems look uniform only because ensemble measurements average over their most interesting molecules. Electron-transfer rates vary across electrode surfaces; lipid membranes contain nanodomains with distinct packing and fluidity; peptide aggregates exhibit local polymorphism; and biomolecular condensates contain transient networks of interactions that are blurred in ensemble images. A central challenge in chemical imaging is not simply to see smaller structures, but to measure chemical variables such as polarity, redox potential, and molecular confinement at the single-molecule level. In this Account, we describe how fluorogens, molecules whose brightness, blinking, spectral shifts, orientation, rotational mobility, and motion are directly shaped …
Enhanced Transdermal Immunization Via Solid-In-Oil Nanodispersions Incorporating Dendritic Cell-Targeting Peptide, Md Samiul Islam, Md. Shahin Ekka Sarker, Yoshirou Kawaguchi, Rie Wakabayashi, Noriho Kamiya, Muhammad Moniruzzaman, Masahiro Goto
Enhanced Transdermal Immunization Via Solid-In-Oil Nanodispersions Incorporating Dendritic Cell-Targeting Peptide, Md Samiul Islam, Md. Shahin Ekka Sarker, Yoshirou Kawaguchi, Rie Wakabayashi, Noriho Kamiya, Muhammad Moniruzzaman, Masahiro Goto
Publications and Research
Transdermal immunization represents a promising needle-free alternative to conventional vaccination. However, efficient antigen delivery and robust immune activation remain major challenges. In this study, a solid-in-oil (S/O) nanodispersion system comprising a dendritic cell-targeting peptide (HR8), ovalbumin (OVA), and an adjuvant was developed for transdermal immunization. The HR8 peptide along with OVA was successfully incorporated into an S/O nanodispersion with an optimal hydrodynamic diameter of particles (< 200 nm) and exhibited stable physical properties for up to 90 days. In vitro and in vivo studies demonstrated enhanced antigen delivery with insignificant skin irritation in C57BL/6N mice. Moreover, in vivo transdermal immunization studies demonstrated that the addition of the HR8 peptide enhanced OVA-specific IgG responses (~1.5-fold). Notably, the HR8 peptide also promoted an approximately 2.5-fold increase in IgG2c levels, suggesting a shift toward a more T helper type 1-biased immune response, as reflected by an increased IgG2c/IgG1 ratio. Overall, these findings demonstrate that the incorporation of HR8 peptide into an S/O nanodispersion enables efficient transdermal antigen delivery and improved immunogenicity, highlighting its potential as a simple, non-invasive, and patient-friendly immunization strategy.
Laminarin-Loaded Solid-In-Oil Nanodispersion For Enhanced Non-Invasive Transdermal Immunization, Md. Shahin Ekka Sarker, Yoshirou Kawaguchi, Rie C. Wakabayashi, Noriho J. Kamiya, Muhammad Moniruzzaman, Masahiro Goto
Laminarin-Loaded Solid-In-Oil Nanodispersion For Enhanced Non-Invasive Transdermal Immunization, Md. Shahin Ekka Sarker, Yoshirou Kawaguchi, Rie C. Wakabayashi, Noriho J. Kamiya, Muhammad Moniruzzaman, Masahiro Goto
Publications and Research
Simple and non-invasive transdermal vaccination is an attractive alternative to conventional injection-based immunization. However, the effectiveness of transdermal vaccines is often constrained by the stratum corneum barrier. Although the use of solid-in-oil (S/O) nanodispersion technology has successfully facilitated skin permeation to induce an immunological response, the antibody titers remain suboptimal. Herein, a dectin-1 selective ligand, laminarin, was used as an immunostimulatory adjuvant to enhance the immune response. S/O nanodispersions loaded with laminarin and ovalbumin (OVA) were systematically developed and characterized in terms of particle size, in vitro OVA release behavior, and skin permeation performance using excised mouse skin. In vivo …
Structure And Spectroscopy Of Free Base, Copper, And Zinc Tetrapentylporphyrin, Christopher J. Ziegler, Nneka Damola Ajayi, Victor N. Nemkyin, G Richard Geier Iii
Structure And Spectroscopy Of Free Base, Copper, And Zinc Tetrapentylporphyrin, Christopher J. Ziegler, Nneka Damola Ajayi, Victor N. Nemkyin, G Richard Geier Iii
University Research
Synthetic porphyrins have been crucial as models for heme units and other biological porphyrins, as well as components of advanced materials and catalysts. Much of the work on synthetic porphyrins has focused on the meso-substituted 5,10,15,20-tetraphenylporphyrin (TPP) or the pyrrole-substituted 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP). In this report, we present a comprehensive spectroscopic, electrochemical, and computational study of free-base, zinc(II), and copper(II) 5,10,15,20-tetrapentylporphyrin (TPeP). TPeP can be prepared via a two-step, one-flask reaction of pyrrole and hexanal mediated by Montmorillonite K10, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in yields of around 40%. Similar to TPP, the TPeP systems have the highest occupied molecular …
Structure And Spectroscopy Of Free Base, Copper, And Zinc Tetrapentylporphyrin, Christopher J. Ziegler, Nneka Damola Ajayi, Victor N. Nemkyin, G Richard Geier Iii
Structure And Spectroscopy Of Free Base, Copper, And Zinc Tetrapentylporphyrin, Christopher J. Ziegler, Nneka Damola Ajayi, Victor N. Nemkyin, G Richard Geier Iii
University Research
Synthetic porphyrins have been crucial as models for heme units and other biological porphyrins, as well as components of advanced materials and catalysts. Much of the work on synthetic porphyrins has focused on the meso-substituted 5,10,15,20-tetraphenylporphyrin (TPP) or the pyrrole-substituted 2,3,7,8,12,13,17,18-octaethylporphyrin (OEP). In this report, we present a comprehensive spectroscopic, electrochemical, and computational study of free-base, zinc(II), and copper(II) 5,10,15,20-tetrapentylporphyrin (TPeP). TPeP can be prepared via a two-step, one-flask reaction of pyrrole and hexanal mediated by Montmorillonite K10, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in yields of around 40%. Similar to TPP, the TPeP systems have the highest occupied molecular …
Interview With Orca Winner Xiao Cheng Zeng; Unl Chemistry; Computational/Theoretical; Nebraska Ice & Gold Nanocages, Mark Griep, Xiao Cheng Zeng
Interview With Orca Winner Xiao Cheng Zeng; Unl Chemistry; Computational/Theoretical; Nebraska Ice & Gold Nanocages, Mark Griep, Xiao Cheng Zeng
UNL ORCA Interview Series
Xiao Cheng Zeng became a chemistry professor at the University of Nebraska-Lincoln in 1993, quickly rose through the ranks, and was in the department for 29 years. In 2022, he left to become head of the Department of Materials Science and Engineering at the City University of Hong Kong. Xiao was born in Beijing and earned a bachelor’s in physics at the University of Beijing in 1984. Next, he traveled 6800 miles east to Ohio State University in Columbus where he earned his doctorate in condensed matter physics. He followed that up with two postdoctoral experiences, first at the University …
Evaluating The Applicability Of Gamess For Determining Bond Lengths And Bond Dissociation Energies Through Constructing Potential Energy Curves For H2, N2, F2, Cl2, And Br2, Iaroslavna Kovalenko, Jillian Pabalan
Evaluating The Applicability Of Gamess For Determining Bond Lengths And Bond Dissociation Energies Through Constructing Potential Energy Curves For H2, N2, F2, Cl2, And Br2, Iaroslavna Kovalenko, Jillian Pabalan
Research and Creativity Symposium
The applicability and limitations of the GAMESS dihydrogen potential energy curve computational tool were evaluated for the following diatomic molecules: H2, N2, F2, Cl2, and Br2. The aug-cc-pVDZ basis set and the B3LYP density functional theory (DFT) functional were employed to ensure more accurate electronic energy results for each calculation. Potential energy curves were generated for each molecule by plotting the electronic energy as a function of interatomic distance, and the bond dissociation energies (BDEs) and radii of diatomic molecules were determined. The radii were determined to be 76 pm …
Elucidating The Structure And Binding Nature Of Thianaphthene Dimers Using Gas-Phase Infrared Spectroscopy, Gaia Zucali, Vincent J. Esposito, Sandra Brünken, Piero Ferrari
Elucidating The Structure And Binding Nature Of Thianaphthene Dimers Using Gas-Phase Infrared Spectroscopy, Gaia Zucali, Vincent J. Esposito, Sandra Brünken, Piero Ferrari
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Crucial for many biological systems, in astrochemistry, and for fundamental chemistry in general, the conformations adopted by weakly bound complexes of polycyclic aromatic hydrocarbons (PAHs) have been the focus of debate for decades. Still, there are great challenges in forming such complexes in the laboratory, measuring accurate spectroscopic information sensitive to structure, and computing molecular properties for systems subtly bound by dispersive interactions. Here, we employ a combination of gas-phase infrared spectroscopy with extensive density functional theory (DFT) calculations to unambiguously determine the preferred conformation adopted by dimers of neutral thianaphthene, a PAH composed of one six- and one five-membered …
Non-Redundant Rovibrational Hamiltonians By Molien Generating Functions And Gröbner-Basis Reduction, Leandro Ajo
Non-Redundant Rovibrational Hamiltonians By Molien Generating Functions And Gröbner-Basis Reduction, Leandro Ajo
University Libraries Undergraduate Research Award
High-resolution molecular spectroscopy requires an effective Hamiltonian whose operator content is both complete, containing every term allowed by molecular symmetry and nonredundant, free of any algebraically dependent operators that would cause ill-conditioned parameter fits. Traditional derivations based on Van Vleck contact transformations satisfy neither criterion automatically. This paper develops a rigorous, algorithmic pipeline that guarantees both properties simultaneously. Starting from the permutation– inversion (PI) group GPI of a molecule (Longuet-Higgins, 1963), we apply Molien’s theorem (Molien, 1897) to the symplectic normal-coordinate representation to obtain the vibrational generating function Φvib(t); integrate over the Haar measure of SO(3) (Weyl, 1946) to obtain …
2026 Research Day Program, Lincoln Memorial University
2026 Research Day Program, Lincoln Memorial University
Research Day
This program contains abstracts and presentation summaries from LMU's 2026 Annual Research Day conference.
Intramolecular Nonbonding Interactions And Geared Phenyl Twisting In Para-Disubstituted 1,4-Diphenylazines: Electron Correlation Effects On Molecular Conformations And Enantiomerization, Kaidi Yang, Harmeet Bhoday, Rainer Glaser
Intramolecular Nonbonding Interactions And Geared Phenyl Twisting In Para-Disubstituted 1,4-Diphenylazines: Electron Correlation Effects On Molecular Conformations And Enantiomerization, Kaidi Yang, Harmeet Bhoday, Rainer Glaser
Chemistry Faculty Research & Creative Works
The results are reported of potential energy surface (PES) analyses of six symmetrical azines Yp − Ph − RC=N − N=CR − Ph − Yp, namely, the benzaldehyde azines 1H, 2H, and 8H with R = H and the acetophenone azines 1M, 2M, and 8M with R = Me. The Y substituents Cl (1), Br (2), and Me (8) were studied because sets of polymorphs I (C2-symmetry, azine twist τ ≈ 135 ± 10°, disrotatory phenyl twists ϕi ≠ 0°) and II (Ci-symmetry, τ = 180°, conrotatory ϕi ≠ 0°) were crystallized for these three azines. The …
Long-Range Fit: A Software Package For The Representation And Study Of Long-Range Molecular Interactions, Adrian L. Batista-Planas, Ernesto Quintas-Sánchez, Richard Dawes
Long-Range Fit: A Software Package For The Representation And Study Of Long-Range Molecular Interactions, Adrian L. Batista-Planas, Ernesto Quintas-Sánchez, Richard Dawes
Chemistry Faculty Research & Creative Works
Describing intermolecular forces is fundamental to modeling and predicting the behavior of molecular systems. In particular, long-range molecular interactions with electrostatic, induction, and dispersion as the main components play a critical role, especially for low-temperature and low-density regimes. Long-range interactions are often described through perturbation theory, representing the electronic charge distribution via a multipolar series of the moments and polarizability tensors corresponding to each molecule. However, while the theory is well established, obtaining the resulting analytical expressions (and their practical implementation) constitutes a highly complex and system-dependent task. To address this challenge, we developed long-range-fit (LRF), an interactive and user-friendly …
Parameter-Free Determination Of Au Nanorod Dimensions Using Depolarized Dls And Genetic Optimization, Nehal Nupnar, Geofrey Nyabere, Claire M.B. Bolding, Kiril A. Streletzky, Michael J.A. Hore
Parameter-Free Determination Of Au Nanorod Dimensions Using Depolarized Dls And Genetic Optimization, Nehal Nupnar, Geofrey Nyabere, Claire M.B. Bolding, Kiril A. Streletzky, Michael J.A. Hore
Physics Faculty Publications
Gold nanorods (AuNRs) have received considerable attention for their distinctive optical properties and well-defined, low-polydispersity dimensions. These characteristics position them as promising candidates for diverse applications in imaging, sensing, and treating diseases. However, accurate characterization of AuNRs in their native solution state, which is crucial to many applications, presents many challenges─especially if AuNRs are coated with surface layers (e.g., surfactants or grafted polymers). When applied to AuNRs with functionalized surfaces, common techniques such as transmission electron microscopy (TEM), small-angle scattering, and dynamic light scattering (DLS) can present limitations such as small sample sizes, the inability to detect light elements, a …
Efficient Organic Molecular Crystal Structure Prediction Using The Density Functional Tight-Binding Method, Maureen M. Kitheka, Yan Jing, Yan Yao, Puja Goyal
Efficient Organic Molecular Crystal Structure Prediction Using The Density Functional Tight-Binding Method, Maureen M. Kitheka, Yan Jing, Yan Yao, Puja Goyal
Faculty Publications – Chemistry
Over the years, computational crystal structure prediction (CSP) for organic molecules has thrived as an area of research, spanning various scientific disciplines and having significant applications in industries such as pharmaceuticals and agrochemicals. Within the field of batteries, redox-active organic materials (ROMs) such as quinones have received increased attention as promising electrode materials for rechargeable batteries. However, experimental determination of the crystal structure of intermediate species formed during the discharge/charge cycle can often be challenging. Incomplete X-ray diffraction patterns can also lead to difficulties in crystal structure determination for ROMs used in batteries. Use of a semiempirical electronic structure method …
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
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, …
Hot Ground State Cooling Following Ultrafast Photoisomerization: Time-Resolved Infrared Spectroscopy, James N. Bull, Mark H. Stockett, Pratip Chakraborty, Eleanor K. Ashworth, Anam Fatima, Vincent J. Esposito, Gregory M. Greetham, Partha Malakar, Stephen R. Meech
Hot Ground State Cooling Following Ultrafast Photoisomerization: Time-Resolved Infrared Spectroscopy, James N. Bull, Mark H. Stockett, Pratip Chakraborty, Eleanor K. Ashworth, Anam Fatima, Vincent J. Esposito, Gregory M. Greetham, Partha Malakar, Stephen R. Meech
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The ultrafast photophysics of many isomerizing molecules involves subpicosecond formation of a twisted hot ground state, which transfers energy to the environment through vibrational relaxation (cooling) over several picoseconds. In time-resolved infrared (TR-IR) spectroscopy, hot ground state transients show frequency shifts and band reshapings, which cannot be described through kinetic models that assume static spectral functions. We report a simple anharmonic cascade framework, which uses a single adjustable parameter associated with scaling the probability of vibrational energy transfer to the environment, for describing hot ground state cooling (HGSC) in TR-IR spectroscopy. The model is demonstrated against measurements on the cyan …
Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis
Catalytic Synthesis Of Iron-Doped Graphitic Aerogels From Poly(Phloroglucinol-Terephthalaldehyde – Urethane) Precursors, Stephen Yaw Owusu, Rushi U. Soni, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
We report a new class of graphitic carbon aerogel precursors based on iron oxide-doped poly(phloroglucinol-terephthalaldehyde–urethane) (T-POL/PU-FeOx) networks. The hybrid polymeric network incorporates a rigid aromatic triisocyanate, tris(4-isocyanatophenyl)methane, which reacts in situ with the hydroxyl groups of phloroglucinol to form a polyurethane-containing framework. Monolithic aerogels derived from this system undergo catalytic graphitization at significantly reduced temperatures (800–1500 °C) compared to conventional graphitization (2500–3300 °C). An oxidative ring fusion aromatization step (240 °C, air) prior to pyrolysis enhanced the degree of graphitization. The resulting graphitic aerogels were characterized by XRD, Raman spectroscopy, TGA, TEM, SEM, XPS, and N₂ sorption porosimetry. Compared to …
Experimental And Anharmonic Theoretical Spectroscopic Benchmarks Of Nitrogenated And Doubly-Nitrogenated Polycyclic Heterocycles, Selma Bejaoui, Brant E. Billinghurst, Christiaan Boersma, Vincent J. Esposito
Experimental And Anharmonic Theoretical Spectroscopic Benchmarks Of Nitrogenated And Doubly-Nitrogenated Polycyclic Heterocycles, Selma Bejaoui, Brant E. Billinghurst, Christiaan Boersma, Vincent J. Esposito
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
In this study, we report the first high-resolution gas-phase infrared absorption spectra and anharmonic vibrational simulations for three nitrogenated aromatic molecules, namely indole (C8H7N), 1,5-diazabicyclo[4.3.0]non-5-ene (DBN; C7H12N2), and 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU; C9H16N2) with excellent agreement between measurement and computation. Anharmonic cascade emission spectra (2–8 eV) of the three systems show that nitrogen substitution strongly modifies the emission spectra: indole reproduces the unidentified 3.3 μm emission in Titan’s atmosphere, while DBN and DBU exhibit redshifted aliphatic C–H stretches. In the 5–10 μm region, …
Collisional Excitation Of Hcn By Co To Refine The Modeling Of Cometary Comae, Francesca Tonolo, Ernesto Quintas-Sánchez, Adrian Batista-Planas, Richard Dawes, François Lique
Collisional Excitation Of Hcn By Co To Refine The Modeling Of Cometary Comae, Francesca Tonolo, Ernesto Quintas-Sánchez, Adrian Batista-Planas, Richard Dawes, François Lique
Chemistry Faculty Research & Creative Works
We present the first dataset of collisional (de)-excitation rate coefficients of HCN induced by CO, one of the main perturbing gases in cometary atmospheres. The dataset spans the temperature range of 5–50 K. It includes both state-to-state rate coefficients involving the lowest ten and nine rotational levels of HCN and CO, respectively, and the so-called "thermalized" rate coefficients over the rotational population of CO at each kinetic temperature. The derivation of these coefficients exploited the good performance of the statistical adiabatic channel model (SACM) on top of an accurate interaction potential computed at the CCSD(T)-F12b/CBS level of theory. The reliability …
Revisiting The Spin–Lattice Relaxation Of Homonuclear In-Phase And Antiphase Nmr Magnetization, Lauren M. Kehoe, Zachary G. Mayes, Kelsey E. Brakensiek, Emma L. Ellis, Adam J. Alderfer, Lingyu Chi, Klaus Woelk
Revisiting The Spin–Lattice Relaxation Of Homonuclear In-Phase And Antiphase Nmr Magnetization, Lauren M. Kehoe, Zachary G. Mayes, Kelsey E. Brakensiek, Emma L. Ellis, Adam J. Alderfer, Lingyu Chi, Klaus Woelk
Chemistry Faculty Research & Creative Works
Hyperpolarization techniques such as dynamic nuclear polarization (DNP), chemically induced dynamic nuclear polarization (CIDNP), and parahydrogen-induced polarization (PHIP) enhance the sensitivity of NMR spectroscopy and MRI, but the associated antiphase magnetization patterns often relax faster than those of conventional in-phase signals. This study analyzes the spin–lattice relaxation matrix for single-quantum transitions in an isolated, weakly coupled two-spin AX system to identify eigenvectors and eigenvalues that govern the time evolution of in-phase and antiphase longitudinal magnetization. The analysis predicts that AX antiphase magnetization, such as that generated by PHIP hydrogenations in high magnetic field, can relax up to twice as fast …
Unveiling The Interplay Of Electronic And Phononic Excitations In Laser-Induced Oxygen Activation On Ru(0001), Xiangrui Wang, Jiamin Wang, Paul Spiering, Liping Liu, Jörg Meyer, Jerry L. Larue, Hongliang Xin
Unveiling The Interplay Of Electronic And Phononic Excitations In Laser-Induced Oxygen Activation On Ru(0001), Xiangrui Wang, Jiamin Wang, Paul Spiering, Liping Liu, Jörg Meyer, Jerry L. Larue, Hongliang Xin
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Understanding laser-induced dynamics on metal surfaces poses significant challenges due to the intricate interplay between electronic and phononic degrees of freedom, which evolve on distinct timescales. In this study, we introduce a machine learning-accelerated approach to molecular dynamics simulations that incorporates anisotropic electronic friction, providing deeper insights into these complex processes. Our framework extends the accessible time and length scales for nonadiabatic dynamics simulations, enabling a detailed investigation of the laser-induced activation of oxygen on the Ru(0001) surface. Statistical analysis reveals that strong electronic excitation dominates the first 800 fs after laser exposure. Beyond this timescale, energy deposited by electronic …
An Experiment In Electron Paramagnetic Resonance Spectroscopy For Undergraduate Labs In Physical Chemistry Or Physical Biochemistry, Evan A. Old, Matthew C. Rehak, Jefferson C. Thompson, Herbert J. Sipe Jr.
An Experiment In Electron Paramagnetic Resonance Spectroscopy For Undergraduate Labs In Physical Chemistry Or Physical Biochemistry, Evan A. Old, Matthew C. Rehak, Jefferson C. Thompson, Herbert J. Sipe Jr.
TeachEPR Submissions
We report a biochemically based EPR experiment for undergraduate laboratories that will serve as instruction for learning EPR sample preparation, spectral observation, and spectral analysis. There is a current lack of EPR instructional experiments that present complex spectra in which computational analysis may be required. The biochemical oxidation system of horse radish peroxidase (HRP) activated by H2O2 acts on 2,6-di-t-butyl-4-hydroxyanisole (DTBHA) to form phenoxyl radicals. This experiment produces moderately complex spectra of moderately long-lived radicals using relatively small amounts of readily available reactants. Spectrum analysis and simulation is accomplished using software freely available on-line. If desired, EPR …
High-Capacity, Reversible, And Energy-Efficient Water Vapor Sorption By Hierarchical Micro-To-Macroporous Carbon Aerogels From Polybenzoxazine And Polybenzodiazine, Vaibhav A. Edlabadkar, Rushi U. Soni, Stephen Y. Owusu, A. B.M.Shaheen Ud Doulah, Nicholas Leventis, Chariklia Sotiriou-Leventis
High-Capacity, Reversible, And Energy-Efficient Water Vapor Sorption By Hierarchical Micro-To-Macroporous Carbon Aerogels From Polybenzoxazine And Polybenzodiazine, Vaibhav A. Edlabadkar, Rushi U. Soni, Stephen Y. Owusu, A. B.M.Shaheen Ud Doulah, Nicholas Leventis, Chariklia Sotiriou-Leventis
Chemistry Faculty Research & Creative Works
Quantitative, reversible water vapor sorption is in rising demand for applications ranging from home appliances to atmospheric water harvesting. However, most sorbents suffer from low water-uptake capacities, nonreusability, and especially high regeneration temperatures. This study addresses this challenge by introducing polybenzoxazine- (PBO) and polybenzodiazine-derived (PBDAZ) carbon aerogels as reversible high-capacity desiccants. PBO and PBDAZ aerogels were prepared from structurally related monomers via HCl-catalyzed ring opening polymerization. Both types of aerogels were first aromatized at 200–240 °C under air or O2 and then were carbonized at 800 °C under Ar. These as-prepared carbon aerogels were further etched at 1000 °C under …
Simulating Chemiluminescence Spectra Of Oh Radical Using Quantum Dynamical Simulations, Triet M. Cao
Simulating Chemiluminescence Spectra Of Oh Radical Using Quantum Dynamical Simulations, Triet M. Cao
Research from the Berry Summer Thesis Institute, 2025
Chemiluminescence is a phenomenon of light emission that occurs when molecules transition from an excited state to the ground state. This phenomenon is widely utilized in applications ranging from quantifying product yields in chemical reactions to biological imaging and atmospheric chemistry studies. It has also been used in many crucial applications in the scarce conditions of heat and electricity, such as light sources for astronomy discovery or deep-sea diving. A notable example of such reactions is combustion, where highly reactive hydroxyl radicals (OH) are products. These radicals exhibit a chemiluminescence spectrum because of the interaction between their ground state and …
Effect Of Bond Strength Variation And Ionizing Radiation On Mutations In Cytosine-Guanine Islands, Joshua Robert Bedwell, Yan Poniatovskyi, Vola Andrianarijaona
Effect Of Bond Strength Variation And Ionizing Radiation On Mutations In Cytosine-Guanine Islands, Joshua Robert Bedwell, Yan Poniatovskyi, Vola Andrianarijaona
Achieve
Ionizing radiation produces free electrons within cells which then ionizes DNA and has the potential to cause carcinogenic mutations. Cytosine-Guanine (CpG) islands are regions that are rich in cytosine and guanine bases and are common sites of single point mutations and strand breaks. In this study, density function theory (DFT) is used to calculate the potential energy of DNA nucleotide dimers varying bond lengths in five different ionized states. Crossing between two ionized states can be seen in the potential energy curves, indicating the possibility of natural transition between the two states. Potential energy curves are used to determine bond …