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Articles 1 - 30 of 177
Full-Text Articles in Astrophysics and Astronomy
An Ion-Neutral Reaction To Form Cyanobenzene And Ethynylbenzene In Titan’S Atmosphere, Rachel M. Huchmala, Vincent J. Esposito
An Ion-Neutral Reaction To Form Cyanobenzene And Ethynylbenzene In Titan’S Atmosphere, Rachel M. Huchmala, Vincent J. Esposito
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The ion-neutral reaction between cyanoacetylene (HC3N) and phenyl anion (C6H5–) leads to the formation of cyanobenzene (C6H5CN) and the ethynyl anion (C2H–) via a submerged, exothermic pathway. Through a different mechanism, the same two reactants also form ethynylbenzene (C6H5C2H) and CN–. These new reactions can be a foundation for the production of substituted benzenes using molecules currently present on Saturn’s largest moon, Titan. Cyclic aromatic molecules like C6H5CN and C6H5 …
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 …
The Computed Microwave Spectrum Of The Protonated Fullerene C60H+, Laszlo Nemes, Jos Oomens, Vincent J. Esposito, Vincent Boudon, Alexander G. G. M. Tielens
The Computed Microwave Spectrum Of The Protonated Fullerene C60H+, Laszlo Nemes, Jos Oomens, Vincent J. Esposito, Vincent Boudon, Alexander G. G. M. Tielens
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The largest known molecule in the interstellar medium of galaxies, C60, has been detected in its neutral and cationic form through its vibrational, UV-driven fluorescence emission spectrum and its electronic absorption spectrum, respectively. The detection of several polycyclic aromatic hydrocarbon molecules through their pure rotation spectrum in cold, dense, molecular cloud cores suggests that C60 might be present in these environments as well. The low flux of UV pumping photons in molecular cloud cores and the absence of suitably bright background stars, make detection of C60 and its cation through the commonly used methods impractical. As …
Tellurium Selenide Quantum Wires Synthesized By Pulsed Laser Ablation In Liquids, Rajendra Subedi, Francisco Ruiz-Zepeda, Iono Hill, Geraldine Hallais, Etienne Herth, Gregory Guisbiers
Tellurium Selenide Quantum Wires Synthesized By Pulsed Laser Ablation In Liquids, Rajendra Subedi, Francisco Ruiz-Zepeda, Iono Hill, Geraldine Hallais, Etienne Herth, Gregory Guisbiers
Faculty Scholarship
Tellurium–selenide (TexSe1-x) binary alloys are promising chalcogenide systems with tunable optoelectronic properties, yet their synthesis in quantumly confined one-dimensional forms remains limited. Here, we report the synthesis of TexSe1-x quantum wires (QWs) via a two-step pulsed laser ablation in liquids (PLAL) approach, enabling surfactant-free formation of alloyed nanostructures under non-equilibrium conditions. A tellurium colloid is first generated and subsequently exposed to selenium ablation, promoting in-situ alloying through repeated plasma-bubble interactions at high repetition rate. The resulting QWs exhibit an average diameter of ~17 ± 4 nm and a length of ~475 ± 46 nm. Structural and chemical analyses (XRD, Raman, …
Interfacial Redox Mediation By Amine/Alkyne-Functionalized Silicon Nanoparticles: Surfactant-Free Gold Nanoparticle Synthesis, Amber L. Garcia, Brittany Griggs, Brian S. Mitchell, Mark J. Fink, Julie P. Vanegas
Interfacial Redox Mediation By Amine/Alkyne-Functionalized Silicon Nanoparticles: Surfactant-Free Gold Nanoparticle Synthesis, Amber L. Garcia, Brittany Griggs, Brian S. Mitchell, Mark J. Fink, Julie P. Vanegas
Physics & Astronomy Faculty Publications
We develop a surfactant-free synthesis method for gold nanoparticles (AuNPs) using 2-propynylamine-functionalized silicon nanoparticles as integrated redox-active supports. Surface-anchored amine groups act as built-in reducing sites for Au3+ precursors at the hexane–water interface under ambient conditions, enabling in situ AuNP nucleation and growth. Time-resolved UV-vis spectroscopy and dynamic light scattering track the emergence of plasmonic AuNPs, while quantitative morphology analysis reveals a final population dominated by spherical and near-spherical nanoparticles (∼74%), with faceted polyhedral structures (∼4%) and dendritic, hollow, irregular, and rod-like morphologies (∼22%) as minority species. The temporal evolution proceeds from early dendritic and irregular aggregates to a …
Detection Of C60 Combination Bands In The Near-Ir Spectrum Of Tc 1, Morgan M. Giese, Vincent J. Esposito, Simon Van Schuylenbergh, Jan Cami, Els Peeters, Charmi Bhatt, Dries Van De Putte, A. G. G. M. Tielens, Michael J. Barlow, Jeronimo Bernard-Salas, Alessandra Candian, Bryan Changala, Nick L. J. Cox, Harriet L. Dinerstein, D. A. García-Hernández, Marco A. Gómez-Muñoz, Kay Justtanont, Kathleen E. Kraemer, Eric Lagadec, Arturo Manchado, Ana Monreal Ibero, Raghvendra Sahai, Ameek Sidhu, G. C. Sloan, N. C. Sterling, Jeremy R. Walsh, Roger Wesson, Joshua Cole Whitman, Albert Zijlstra
Detection Of C60 Combination Bands In The Near-Ir Spectrum Of Tc 1, Morgan M. Giese, Vincent J. Esposito, Simon Van Schuylenbergh, Jan Cami, Els Peeters, Charmi Bhatt, Dries Van De Putte, A. G. G. M. Tielens, Michael J. Barlow, Jeronimo Bernard-Salas, Alessandra Candian, Bryan Changala, Nick L. J. Cox, Harriet L. Dinerstein, D. A. García-Hernández, Marco A. Gómez-Muñoz, Kay Justtanont, Kathleen E. Kraemer, Eric Lagadec, Arturo Manchado, Ana Monreal Ibero, Raghvendra Sahai, Ameek Sidhu, G. C. Sloan, N. C. Sterling, Jeremy R. Walsh, Roger Wesson, Joshua Cole Whitman, Albert Zijlstra
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
We report the detection of a set of new near-infrared emission features between 3.5 and 5.2 μm in JWST/NIRSpec observations of Tc 1, the planetary nebula known for displaying the cleanest and most prominent mid-infrared cosmic fullerene spectrum. These broad features share the same spatial distribution as the well-known C60 and C70 mid-infrared emission bands, peaking in an asymmetric ring approximately 5″–6″ from the central star. Through comparison with new anharmonic quantum chemical calculations, we demonstrate that these features arise from C60 combination bands, marking their first detection in an astrophysical environment. The total energy radiated …
Table Of Contents
Journal of the South Carolina Academy of Science
No abstract provided.
Spectroscopy And Photochemistry Of The Astrochemical Molecules Sicp And Alcp, Vincent J. Esposito, Tarek Trabelsi, Rebecca Firth, Ryan C. Fortenberry, Joseph S. Francisco
Spectroscopy And Photochemistry Of The Astrochemical Molecules Sicp And Alcp, Vincent J. Esposito, Tarek Trabelsi, Rebecca Firth, Ryan C. Fortenberry, Joseph S. Francisco
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Through characterization of the electronic excited-state topology, linear-SiCP is predicted to be photostable in the UV region, whereas linear-AlCP is predicted to undergo photodissociation to form Al+CP products after absorption of light in the 200–250 nm range, representing a catalytic process for freeing aluminum molecules from a solid dust grain. Both SiCP and AlCP are predicted to have electronic transitions with large absorption cross sections (∼10–17 cm2) and to undergo fluorescence from bound excited states. The total electronic absorption spectrum is provided to inform electronic spectroscopy experiments. Silicon (SiC) and aluminum (Al2O3) dust …
An Updated Infrared Solar Spectrum From Ace-Fts And A Ch Rovibrational Line List, Manish Bhusal, Peter F. Bernath, Léo Lavy, Chris D. Boone, Frank Hase
An Updated Infrared Solar Spectrum From Ace-Fts And A Ch Rovibrational Line List, Manish Bhusal, Peter F. Bernath, Léo Lavy, Chris D. Boone, Frank Hase
Chemistry & Biochemistry Faculty Publications
An updated Atmospheric Chemistry Experiment Fourier Transform Spectrometer infrared solar spectrum has been produced from low-Earth orbit covering 1829-4440 cm-¹ (2.252-5.467 mu m). Spectroscopic constants for the v = 4 and v = 5 vibrational levels of the X²Π state of CH radical have been updated by incorporating additional vibration-rotation lines from the new solar spectrum and from an archival laboratory spectrum. New ab initio calculations of the permanent dipole moment function for the X²Π state were performed with the MOLPRO quantum chemistry package using the internally contracted multireference configuration interaction method. This dipole moment function, along with …
M-Type Star Spectral Analysis: Sco Line List Including The B²Σ⁺-X²Σ⁺ Band System, Léo Lavy, Jacques Liévin, Peter F. Bernath
M-Type Star Spectral Analysis: Sco Line List Including The B²Σ⁺-X²Σ⁺ Band System, Léo Lavy, Jacques Liévin, Peter F. Bernath
Chemistry & Biochemistry Faculty Publications
An analysis of the B²Σ+ − X²Σ+ band system of ⁴⁵Sc¹⁶O is presented. ScO was excited in a hollow cathode discharge, and its Doppler-limited resolution spectrum was measured with a Fourier transform spectrometer. The spectroscopic constants of the B²Σ+ state with v ≤ 3 are reported, and equilibrium constants are derived. Ab initio transition dipole moment functions are calculated for the A²Π − X²Σ+ and B²Σ+ − X²Σ+ transitions and scaled using lifetime measurements. We report new line lists of hyperfine-resolved transitions for ⁴⁵Sc¹⁶O with recalculated Einstein A coefficients and oscillator strengths of the …
Additional Information For Fully Anharmonic Ir 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 C. Fortenberry
Additional Information For Fully Anharmonic Ir 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 C. Fortenberry
Faculty and Student Publications
Interstellar aromatic infrared band (AIB) spectra are showing strong agreement with presently-computed, anharmonic spectra for various types of polycyclic aromatic hydrocarbons (PAH) determined using a novel semi-empirical 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 (C$_{10}$H$_8$) up to circumbiphenyl (C$_{38}$H$_{16}$) are combined giving consideration to almost all PAH structural motifs. The computed, numerical quartic force fields coupled to second-order vibrational perturbation theory clearly confirm that PAH …
A Study On The Great Comet Of 2024: C/2023 A3 (Tsuchinshan–Atlas) Via Radio Interferometry, Jesse Bier, Nathan X. Roth
A Study On The Great Comet Of 2024: C/2023 A3 (Tsuchinshan–Atlas) Via Radio Interferometry, Jesse Bier, Nathan X. Roth
Undergraduate Research Symposium
Our solar system is approximately 4.5 billion years old. Comets are remnants of its formation, serving as time capsules to give us an understanding of its natal heritage. Revealing our own solar system’s history allows us to gain insights into other young stellar systems and the potential for life elsewhere. C/2023 A3 (Tsuchinshan–ATLAS) was a comet from the Oort cloud on its first and possibly only journey to the inner solar system. The comet grew in brightness until it was brighter than Venus on October 9th, 2024, making it temporarily brighter than Venus and one of the brightest …
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, …
Table Of Contents
Journal of the South Carolina Academy of Science
No abstract provided.
A Catalytic Pathway For The Formation Of Cyanobenzene In Nitrogen-Rich Environments And The Spectroscopy Of The Reactive Intermediates, Vincent J. Esposito, Silvia Alessandrini, David Dubois, Ryan Fortenberry
A Catalytic Pathway For The Formation Of Cyanobenzene In Nitrogen-Rich Environments And The Spectroscopy Of The Reactive Intermediates, Vincent J. Esposito, Silvia Alessandrini, David Dubois, Ryan Fortenberry
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
The catalytic reaction of isocyanobenzene (C6H5NC) with NCN− produces cyanobenzene (C6H5NC) through various highly stable reactive intermediate species. Nitrogen-rich environments such as Titan’s atmosphere serve as favorable locations to study reaction pathways involving nitrogenated species contributing to organic growth. Formation pathways of cyanobenzene have been characterized, but none with the contribution of anions or phenyl groups. In regions with a high abundance of nitrogen anions, such as Titan’s atmosphere, reactions with species such as NCN− may play a role in the formation of cyanobenzene. Highly accurate computational methods are used …
A Spectroscopic Survey Of Atmospheres Of Super-Earths, Luke Brust
A Spectroscopic Survey Of Atmospheres Of Super-Earths, Luke Brust
Honors Theses
Recent research has made it possible to use spectroscopy to analyze the composition of the atmospheres of exoplanets, planets that orbit other stars. Most projects thus far have focused on the atmospheres of gas giants, as it is less challenging to observe them with available equipment. This project studies the atmospheres of four Super- Earths, planets that have a mass greater than the Earth but smaller than Neptune. This is accomplished by processing the raw spectroscopic data from the Hubble Space Telescope and modeling the atmosphere using the program 𝝉-Rex3. This survey found clear results from two of the selected …
Infrared Cooling In An Anharmonic Cascade Framework: 2-Cyanoindene, The Smallest Cyano-Pah Identified In Tmc-1, Mark H. Stockett, Vincent J. Esposito, Eleanor K. Ashworth, Ugo Jacovella, James N. Bull
Infrared Cooling In An Anharmonic Cascade Framework: 2-Cyanoindene, The Smallest Cyano-Pah Identified In Tmc-1, Mark H. Stockett, Vincent J. Esposito, Eleanor K. Ashworth, Ugo Jacovella, James N. Bull
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Infrared (IR) cooling of polycyclic aromatic hydrocarbon (PAH) molecules is a major radiative stabilization mechanism of PAHs present in space and is the origin of the aromatic infrared bands (AIBs). Here, we report an anharmonic cascade model in a master equation framework to model IR emission rates and emission spectra of energized PAHs as a function of internal energy. The underlying (simple harmonic cascade) framework for fundamental vibrations has been developed through the modeling of cooling rates of PAH cations and other carboneaous ions measured in electrostatic ion storage ring experiments performed under “molecular cloud in a box” conditions. The …
A Sensitivity Analysis Of The Modeling Of Polycyclic Aromatic Hydrocarbon Emission In Galaxies, A. Maragkoudakis, C. Boersma, P. Temi, J. D. Bregman, L. J. Allamandola, Vincent J. Esposito, A. Ricca, E. Peeters
A Sensitivity Analysis Of The Modeling Of Polycyclic Aromatic Hydrocarbon Emission In Galaxies, A. Maragkoudakis, C. Boersma, P. Temi, J. D. Bregman, L. J. Allamandola, Vincent J. Esposito, A. Ricca, E. Peeters
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
We have conducted a sensitivity analysis on the mid-infrared spectral decomposition of galaxies and the modeling of the polycyclic aromatic hydrocarbon (PAH) emission spectrum with the NASA Ames PAH Infrared Spectroscopic Database (PAHdb) to assess the variance on the average galaxy PAH population properties under a grid of different modeling parameters. We find that the short-low and short-low+long-low Spitzer-IRS decomposition with PAHFIT provides consistent modeling and recovery of the 5–15 μm PAH emission spectrum. For PAHdb modeling, application of a redshift to the calculated spectra to account for anharmonic effects introduces a 15%–20% variance on the derived parameters, while its …
Photolysis And Sublimation Chemistry Of Ammonium Cyanide With Relevance To Cometary Environments, O. H. Wilkins, K. M. Yocum, Vincent J. Esposito, E. Harel, S. N. Milam, P. A. Gerakines
Photolysis And Sublimation Chemistry Of Ammonium Cyanide With Relevance To Cometary Environments, O. H. Wilkins, K. M. Yocum, Vincent J. Esposito, E. Harel, S. N. Milam, P. A. Gerakines
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Bulk nitrogen is depleted in solar system objects, including the terrestrial planets, chondritic meteorites, and comets. Recently, it was suggested that cometary nitrogen may be locked up in ammonium salts—ionic solids comprising ammonia (NH3) and an acid such as hydrogen cyanide (HCN)—based on Rosetta/ROSINA data from comet 67P/Churyumov–Gerasimanko. Among the proposed salts to have been found in 67P were ammonium cyanide (NH4CN) and ammonium cyanate (NH4OCN), which were inferred from identifying HCN, cyanamide (NH2CN), and isocyanic acid (HNCO) in the mass spectrometry data collected in the coma of 67P. However, the relationship …
Experimental Absorption Cross Sections For Zro, Léo Lavy, Peter F. Bernath, Manish Bhusal, Jacques Liévin
Experimental Absorption Cross Sections For Zro, Léo Lavy, Peter F. Bernath, Manish Bhusal, Jacques Liévin
Chemistry & Biochemistry Faculty Publications
Absorption cross sections for ZrO are provided and can be used as a template to interpret spectra of S-type stars. The ZrO spectrum was measured in emission from a carbon furnace at 2700 K and calibrated using synthetic spectra of ⁹⁰Zr¹⁶O. A set of nearly isolated molecular lines has been used for the calibration. We also thoroughly review the literature on the spectroscopy of ZrO. Comparison of the experimental spectrum with currently available line lists revealed issues in ZrO spectral simulation. (a) Within band systems, the relative intensities are not always well reproduced. (b) We identify yet unreported band systems, …
Unraveling Visible Spectra Of S-Type Stars: The F3Δ–A3Δ (Α System) And E3Π–A3Δ (Β System) Band Systems Of Zro, Manish Bhusal, Peter Bernath, Jacques Liévin
Unraveling Visible Spectra Of S-Type Stars: The F3Δ–A3Δ (Α System) And E3Π–A3Δ (Β System) Band Systems Of Zro, Manish Bhusal, Peter Bernath, Jacques Liévin
Chemistry & Biochemistry Faculty Publications
ZrO has many low-lying states, and its spectra are essential for the characterization of S-type stars. A high-resolution emission spectrum recorded with a Fourier transform spectrometer at the National Solar Observatory is used for the analysis. The 0–0 and 1–0 bands of the f³Δ-a³Δ system (α system) and the 0–0 band of the e³Π-a³Δ system (β system) have been rotationally analyzed using the modern spectral fitting program PGOPHER. New ab initio calculations of transition dipole moments have been performed to determine the band strengths. These band strengths are used to produce line lists that are suitable for the …
M Star Opacities: The B³Π–X³Δ Band System Of Tio, Peter F. Bernath, Manish Bhusal, Mirek R. Schmidt
M Star Opacities: The B³Π–X³Δ Band System Of Tio, Peter F. Bernath, Manish Bhusal, Mirek R. Schmidt
Chemistry & Biochemistry Faculty Publications
The spectra of titanium monoxide (TiO) are used to classify M stars. TiO experimental cross sections based on a high-resolution emission spectrum recorded with a Fourier transform spectrometer at the National Solar Observatory are used for the analysis of the TiO B³Π–X³Δ transition (𝛾' system). The 3–2 and 4–3 vibrational bands are analyzed for the first time, and the analysis of the 2–1 band is revised. The transition dipole moment function from an ab initio calculation is used to calculate the band strengths. These band strengths are used to produce a B³Π–X³Δ line list for the vibrational levels v' ⩽ …
The B³Π–A³Δ And B³Π–X¹Σ+ Band Systems Of Zro, Manish Bhusal, Peter F. Bernath, Jacques Liévin, Léo Lavy
The B³Π–A³Δ And B³Π–X¹Σ+ Band Systems Of Zro, Manish Bhusal, Peter F. Bernath, Jacques Liévin, Léo Lavy
Chemistry & Biochemistry Faculty Publications
The zirconium oxide (ZrO) b³Π–a³Δ system is a prominent source of opacity in the atmospheres of S-type stars in the near-infrared region. The emission spectra of ZrO, obtained at the National Solar Observatory located at Kitt Peak in Arizona, have been utilized to analyze this band system. A reanalysis of the 0–0 vibrational band of the b³Π–a³Δ transition has been carried out. For the first time, the vibrational bands with 1 ⩽ v ′ ⩽ 3 and v″ ≤ 4 for the same electronic transition have been rotationally analyzed using PGOPHER. Additionally, the 0–0 and 1–1 bands of the spin-forbidden …
Vibrational And Electronic Spectroscopy Of 2-Cyanoindene Cations, Thomas E. Douglas-Walker, Eleanor K. Ashworth, Mark H. Stockett, Francis C. Daly, Isabelle Chambrier, Vincent J. Esposito, Marius Gerlach, Angel Zheng, Julianna Palotás, Andrew N. Cammidge, Ewen K. Campbell, Sandra BrüNken, James N. Bull
Vibrational And Electronic Spectroscopy Of 2-Cyanoindene Cations, Thomas E. Douglas-Walker, Eleanor K. Ashworth, Mark H. Stockett, Francis C. Daly, Isabelle Chambrier, Vincent J. Esposito, Marius Gerlach, Angel Zheng, Julianna Palotás, Andrew N. Cammidge, Ewen K. Campbell, Sandra BrüNken, James N. Bull
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
2-Cyanoindene is one of the few specific aromatic or polycyclic aromatic hydrocarbon (PAH) molecules positively identified in Taurus molecular cloud-1 (TMC-1), a cold, dense molecular cloud that is considered the nearest star-forming region to Earth. We report cryogenic mid-infrared (550–3200 cm–1) and visible (16,500–20,000 cm–1, over the D2 ← D0 electronic transition) spectra of 2-cyanoindene radical cations (2CNI+), measured using messenger tagging (He and Ne) photodissociation spectroscopy. The infrared spectra reveal the prominence of anharmonic couplings, particularly over the fingerprint region. There is a strong CN-stretching mode at 2177 ± 1 cm–1 (4.593 …
Potential Cell Preservation In Mars-Relevant Clay Minerals, Hanford Gerille Gonzales, Leena M. Cycil, Elisabeth Hausrath
Potential Cell Preservation In Mars-Relevant Clay Minerals, Hanford Gerille Gonzales, Leena M. Cycil, Elisabeth Hausrath
Undergraduate Research Symposium Posters
This study investigates the potential of Fe-nontronite, a clay mineral found on Mars, to preserve biological cells and retain biosignatures such as trace metals. The research explores the preservation potential of nontronite by reacting it with cells under the following conditions: 1) reacting cells with nontronite precursors at low temperature and 2) reacting cells with the already synthesized nontronite made at high temperature. Microbial species Shewanella oneidensis and Geobacter metallireducens, known for their relevance to iron-rich environments, were introduced in intact and lysed forms to assess their interactions with each condition of nontronite. Preliminary results from scanning electron microscopy (SEM) …
Battle Of The Ch Motions: Aliphatic Vs Aromatic Contributions To Astronomical Pah Emission And Exploration Of The Aliphatic, Aromatic, And Ethynyl Ch Stretches, Vincent J. Esposito, Salma Bejaoui, Brant E. Billinghurst, Christiaan Boersma, Ryan C. Fortenberry, Farid Salama
Battle Of The Ch Motions: Aliphatic Vs Aromatic Contributions To Astronomical Pah Emission And Exploration Of The Aliphatic, Aromatic, And Ethynyl Ch Stretches, Vincent J. Esposito, Salma Bejaoui, Brant E. Billinghurst, Christiaan Boersma, Ryan C. Fortenberry, Farid Salama
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Strong anharmonic coupling between vibrational states in polycyclic aromatic hydrocarbons (PAH) produces highly mixed vibrational transitions that challenge the current understanding of the nature of the astronomical mid-infrared PAH emission bands. Traditionally, PAH emission bands have been characterized as either aromatic or aliphatic, and this assignment is used to determine the fraction of aliphatic carbon in astronomical sources. In reality, each of the transitions previously utilized for such an attribution is highly mixed with contributions from both aliphatic and aromatic CH motions as well as non-CH motions such as CC stretches. High-resolution gas-phase IR absorption measurements of the spectra of …
Striatal Beat Frequency Interval Timing Model With Microgravity Stressor, Jason Michael Fitzgerald, Sorinel Oprisan
Striatal Beat Frequency Interval Timing Model With Microgravity Stressor, Jason Michael Fitzgerald, Sorinel Oprisan
Journal of the South Carolina Academy of Science
The Striatal Beat Frequency (SBF) model of interval timing uses frontal cortex (FC) neural oscillations to record the state of the brain at the reinforcement time Tc during fixed interval (FI) procedures in the long-term memory (LMEM). The state of the FC oscillators at any given time is stored in a short-term memory (SMEM) buffer. The SBF model uses the spiny neurons of the basal ganglia (BG) as coincidence detectors to produce beats between the content of the SMEM and LMEM. Across multiple species that can perform interval timing, there are two invariant properties: (a) the timing is precise, and …
On The Formation And Detectability Of H2Cncn And Its Progenitors, Ryan C. Fortenberry, Vincent J. Esposito
On The Formation And Detectability Of H2Cncn And Its Progenitors, Ryan C. Fortenberry, Vincent J. Esposito
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
New highly exothermic formation pathways incorporating both thermodynamic and kinetic control for the newly astronomically detected H2CNCN molecule are paired with extremely accurate quantum chemical rovibrational spectroscopic computations. The reactions between astronomically known CH2CN/CH2CCH + HNCN follow effectively identical pathways and proceed through stable intermediates and over deeply submerged transition states to form H2CNCN and HCN/HCCH coproducts. Similarly, the reaction between CHM2CN and NCN− can also form H2CNCN, although this pathway first requires the initial formation of NCN−, which is currently undetected in space, via …
Experimental Determination Of The Unusual Ch Stretch Frequency Of Protonated Fullerenes, Laura Finazzi, Vincent J. Esposito, Julianna Palotás, Jonathan Martens, Els Peeters, Jan Cami, Giel Berden, Jos Oomens
Experimental Determination Of The Unusual Ch Stretch Frequency Of Protonated Fullerenes, Laura Finazzi, Vincent J. Esposito, Julianna Palotás, Jonathan Martens, Els Peeters, Jan Cami, Giel Berden, Jos Oomens
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
We report experimental values for the CH stretch frequencies of the protonated fullerenes C60H+ and C70H+. Anharmonic frequency calculations at the B3LYP/6-31G level of theory, which are independent of empirical scaling factors, reproduce the experimental values to within approximately 5 cm−1. Scaling theoretical harmonic frequencies by applying factors derived for polycyclic aromatic hydrocarbons deviate significantly from the experimentally measured frequency. We attribute this deviation to the unusual hydrocarbon structure that affects the degree of anharmonicity of the CH stretch. This result allows us to propose an original, specific scaling factor of …