ACS Earth and Space Chemistry最新文献

{"title":"Single-Crystal Elasticity of α-Hydroquinone-An Analogue for Organic Planetary Materials.","authors":"Jin S Zhang, Wen-Yi Zhou, Tuan H Vu, Robert Hodyss, Xinting Yu","doi":"10.1021/acsearthspacechem.4c00322","DOIUrl":"10.1021/acsearthspacechem.4c00322","url":null,"abstract":"<p><p>In this study, we measured the single-crystal elasticity of α-hydroquinone at ambient conditions using Brillouin spectroscopy to assess the feasibility of this technique for studying the mechanical properties of organic ices in the outer solar system. In this study, α-hydroquinone serves as an ambient temperature analogue for low-temperature organic ices on Titan and other solar system bodies. We found that a satisfactory Brillouin spectrum can be obtained in less than 5 min of experimental time with negligible damage to the sample. The best fit single-crystal elastic moduli of α-hydroquinone were determined as <i>C</i> ₁₁ = 13.67(8) GPa, <i>C</i> ₃₃ = 10.08(6) GPa, <i>C</i> ₄₄ = 4.54(5) GPa, <i>C</i> ₁₂ = 6.9(7) GPa, <i>C</i> ₁₃ = 7.02(7) GPa, <i>C</i> ₁₄ = 0.54(4) GPa, <i>C</i> ₂₅ = 0.51(9) GPa, and <i>C</i> ₆₆ = (<i>C</i> ₁₁ - <i>C</i> ₁₂)/2 = 3.4(3) GPa, with bulk modulus <i>K</i> _S = 8.7(2) GPa and shear modulus <i>G</i> = 3.4(3) GPa. These results demonstrate that Brillouin spectroscopy is a powerful tool for characterizing the elastic properties of organic materials. The elastic properties of organic ices can be broadly applied to understand planetary surface processes and also aid in evaluating the feasibility and technical readiness of future lander, sampling, and rover missions in the outer solar system.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"1-7"},"PeriodicalIF":2.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11744926/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron Enrichment Mechanism in Granular Iron Formation (GIF) of the Wuzhiling Formation, Songshan Group, North China Craton: Implications for Metallogeny","authors":"Boyang Xu,&nbsp;Deshun Zheng*,&nbsp;Fengbo Sun,&nbsp;Bin Tang,&nbsp;Xin Wang and Ting Li,&nbsp;","doi":"10.1021/acsearthspacechem.4c0022010.1021/acsearthspacechem.4c00220","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00220https://doi.org/10.1021/acsearthspacechem.4c00220","url":null,"abstract":"<p >The extensive Paleoproterozoic iron formations (IFs) distributed across the North China Craton serve as ideal proxies for understanding the redox variations in paleo-oceans before and after the Great Oxidation Event (GOE). Here, we present a comprehensive analysis of the lithofacies, mineralogy, and geochemical characteristics of the granular iron formation (GIF) within the Paleoproterozic Wuzhiling Formation of the Songshan Group in the southern North China Craton. Our findings reveal that the GIF represents a chemical sedimentary rock, precipitated within a water column characterized by layered oxygen-depleted to suboxic conditions. The protolith sediments of the GIF in the Wuzhiling Formation are hypothesized to have comprised quartz-coated hematite microparticles, along with precursor deposits of aragonite and hexagonal iron oxides, commonly referred to as green rust. Mineralogically, the GIF is predominantly composed of quartz and hematite, with the iron content attributed to the weathering processes of continental crustal materials, the influence of low-temperature hydrothermal fluids, and the incorporation of iron from seawater. During the GOE, a pivotal transition in Earth’s history, the (Pr/Yb) ratios normalized to PAAS (Post-Archean Australian Shale) standards exhibit increased dispersion, accompanied by a gradual decrease in the Y/Ho ratios. These geochemical shifts suggest a pronounced alteration in the ancient marine environment, transitioning from a monolithic reducing state to a more complex redox stratification within the seawater after the GOE. In summary, this study contributes to the reconstruction of paleo-ocean redox conditions around the GOE, providing evidence for the re-establishment of Precambrian paleoenvironmental conditions.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"92–105 92–105"},"PeriodicalIF":2.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143087019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical Spectroscopy and Photochemistry of Silicon Oxide Cations: The Case of Triatomic Si2O+ and SiO2+","authors":"Taarna Studemund,&nbsp;Kai Pollow,&nbsp;Marko Förstel,&nbsp;Emil Mickein,&nbsp;Alexander A. Breier and Otto Dopfer*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0032610.1021/acsearthspacechem.4c00326","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00326https://doi.org/10.1021/acsearthspacechem.4c00326","url":null,"abstract":"<p >Small silicon oxide compounds are considered crucial in the formation and evolution of stardust, particularly particles with silica and silicate cores. Thus, detailed information on the geometry, energy, electronic structure, reactivity, and photochemistry of small silicon oxides is essential for unraveling the fundamental mechanisms involved in the production and processing of stardust. Herein, the optical spectra of size-selected triatomic Si₂O⁺ and SiO₂⁺ cations are obtained in the range 289.9–709.4 nm (1.75–4.28 eV, 14,100–34,500 cm^–1) by means of electronic photodissociation (EPD) in a tandem mass spectrometer coupled to a laser vaporization source. The EPD spectra are assigned by comparison to density functional theory calculations. The EPD spectrum of Si₂O⁺ observed in the lowest-energy Si⁺ fragment ion channel is characterized by two band systems <b>A</b> and <b>B</b> with maxima observed at 25,202(5) and 30,609(5) cm^–1. Bands <b>A</b> and <b>B</b> are assigned to transitions into the excited D₃(²B₂) and D₆(²B₂) doublet electronic states of the bent isomer <b>II</b> with <i>C</i>_2v symmetry. Resolved vibronic structure of band <b>B</b> is attributed to anharmonic progressions of the symmetric stretching and bending modes, ω₁ = 707(2) and ω₂ = 804(3) cm^–1. The predicted more stable linear isomer <b>I</b> with <i>D</i>_∞h symmetry (Δ<i>E</i>₀ = 0.23 eV) does not have any allowed transition expected in the spectral range investigated and is not observed. In line with the computational prediction, the EPD spectra measured for linear SiO₂⁺ do not reveal any electronic transition, because of its vanishing absorption cross section in the considered spectral range.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"178–190 178–190"},"PeriodicalIF":2.9,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143086519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesis and Structure of Acetylenic Acylium Cations","authors":"Dirk Hollenwäger*,&nbsp;Dominik Leitz,&nbsp;Alexander Nitzer,&nbsp;Valentin Bockmair and Andreas J. Kornath,&nbsp;","doi":"10.1021/acsearthspacechem.4c0025310.1021/acsearthspacechem.4c00253","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00253https://doi.org/10.1021/acsearthspacechem.4c00253","url":null,"abstract":"<p >Acetylenedicarbonyl fluoride and propiolyl fluoride were investigated in the Lewis acidic medium consisting of SbF₅/CF₃CH₂F. The acetylenic acyl cations are characterized by vibrational spectroscopy, NMR spectroscopy, and single-crystal X-ray diffraction. The protonated species of propiolyl fluoride decomposes in a few hours at −78 °C in a dynamic vacuum which leads to the formation of the corresponding acylium cation. The room-temperature stable methylated acyl fluoride was prepared in the ternary system CH₃F/SbF₅/SO₂. The experimental data are discussed together with quantum chemical calculations on the M06-2X/aug-cc-pVTZ level of theory.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"126–133 126–133"},"PeriodicalIF":2.9,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143086752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aircraft Measurements from a U.S. Western Wildfire Demonstrating Day and Night Differences in the Chemical Composition and Optical Properties of Biomass Burning Aerosols and Their Atmospheric Evolution","authors":"Felipe A. Rivera-Adorno,&nbsp;Lisa Azzarello,&nbsp;Michael A. Robinson,&nbsp;Zachary C. J. Decker,&nbsp;Rebecca A. Washenfelder,&nbsp;Katherine Hayden,&nbsp;Alessandro Franchin,&nbsp;Christopher D. Holmes,&nbsp;Cora J. Young,&nbsp;Carley D. Fredrickson,&nbsp;Brett Palm,&nbsp;Chris Schmidt,&nbsp;Amber Soja,&nbsp;Emily Gargulinski,&nbsp;Steven S. Brown,&nbsp;Ann M. Middlebrook and Alexander Laskin*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0021510.1021/acsearthspacechem.4c00215","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00215https://doi.org/10.1021/acsearthspacechem.4c00215","url":null,"abstract":"<p >The composition and transformations of biomass burning aerosols (BBA) have been measured onboard the NOAA Twin Otter research aircraft during the Fire Influence on Regional to Global Environments and Air Quality field study. We analyze real-time aerosol mass spectrometry measurements across three flights during the afternoon, late afternoon, and night of August 28, 2019, for one midsized wildfire. Analysis of several metrics showed that the aerosol composition and optical properties varied depending on the burning conditions at the fire zone and the time of day the BBA was emitted, with substantial variations in the available sunlight. The total aerosol mass loadings were dominated by organic components with a much smaller contribution from inorganic species. A gradual buildup of organic material was observed during the afternoon as the plume aged, indicating the condensation of photochemically formed low-volatility oxidized organic compounds. Highly hygroscopic ammonium nitrate was the main inorganic component, suggesting potential water content in BBA particles and the likelihood of their aqueous-phase reactivity. Depletions of particle-phase NO₃^– and Cl^– relative to carbon monoxide were observed in the late afternoon and nighttime plumes, respectively, aligning with known gas-particle partitioning thermodynamics and the heterogeneous chemistry of dissolved nitrate and chloride. The wavelength-dependent light absorption by aerosol species was higher for the plume sampled at night and showed no significant changes with plume age, despite observed trends in composition and mass downwind. These differences in particle composition and optical properties demonstrate that the processes involved in BBA aging are not uniform for the same wildfire over the course of the day and depend highly on when the BBA was emitted, as well as the burning phase at the emissions source.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"64–75 64–75"},"PeriodicalIF":2.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143085615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanistic Insights into the Silica-Mediated Synthesis of Glyceraldehyde from Glycolaldehyde and Hydroxymethylene","authors":"Gianluca Rinaldi,&nbsp;Zoi Salta and Nicola Tasinato*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0030210.1021/acsearthspacechem.4c00302","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00302https://doi.org/10.1021/acsearthspacechem.4c00302","url":null,"abstract":"<p >Minerals are crucial ingredients in prebiotic chemistry as they could have promoted the evolution of simple organic molecules toward proto-biomolecules that are on the route of the emergence of self-replicating information-rich macromolecules. In this respect, the formose reaction, involving the sequential autocatalytic condensation of formaldehyde, is the generally accepted pathway for sugar synthesis. Although obtained under controlled laboratory conditions with enhanced sugar yields promoted by the presence of silicate in the reaction medium, it presents a number of limitations, and the underlying reaction mechanism remains an unsolved riddle. In this work, the focus is on the second step of the formose reaction, namely, the synthesis of glyceraldehyde, which is accomplished by considering the reaction between glycolaldehyde and hydroxymethylene taking place on the edingtonite mineral. The reaction mechanism is explored by quantum chemical simulations performed at various degrees of sophistication to shed light on the thermochemical and kinetic feasibility of the reaction. The same pathway is also investigated in the gas phase in order to disentangle the role played by the zeolitic mineral. The obtained results show that the exothermic reaction between glycolaldehyde and hydroxymethylene yields glyceraldehyde by a submerged reaction path, both in the gas phase and on the edingtonite surface. The mineral substrate provides further stabilization, by about 20 kcal mol^–1, of all the species involved in the reaction pathway and acts as a scaffold favoring the interaction of the two reactants.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"146–157 146–157"},"PeriodicalIF":2.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143086087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the Mechanism of Hydrogen Cyanide Formation on Metal Surfaces in the Interstellar Medium: A Computational Perspective","authors":"Arun Ramamurthy,&nbsp;Yuvaraj Ravi and Gopi Ragupathy*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0023210.1021/acsearthspacechem.4c00232","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00232https://doi.org/10.1021/acsearthspacechem.4c00232","url":null,"abstract":"<p >By utilizing quantum chemical calculations, we inspect four various reaction pathways for the formation of hydrogen cyanide (HCN) on interstellar medium in two interstellar conditions, i.e., gas phase and metal surface, respectively. We found their reactivity and feasibility of a chemical reaction under both conditions. Additionally, we probe how HCN interacts with metal surfaces to determine the thermodynamic parameters and reactive energetic barriers of the chemical reactions in cosmic environments. The alternative pathways created by the metal considerably lowered the reactive potential barriers, resulting in a notable increase in the reaction rate. From this theoretical research, it is revealed that the catalytic potential of metal surfaces in ISM significantly enhances the feasibility of chemical reactions and becomes the most favorable route for the formation of HCN.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"106–118 106–118"},"PeriodicalIF":2.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143084798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the Stable Isotope Composition of Water in Brine from Halite Fluid Inclusions and Borehole Brine Seeps Using Cavity Ring-Down Spectroscopy","authors":"Daniel L. Eldridge*,&nbsp;Melissa M. Mills,&nbsp;Hayden B. D. Miller,&nbsp;Shawn Otto,&nbsp;Jon E. Davis,&nbsp;Eric J. Guiltinan,&nbsp;Thom Rahn,&nbsp;Kristopher L. Kuhlman and Philip H. Stauffer,&nbsp;","doi":"10.1021/acsearthspacechem.4c0010710.1021/acsearthspacechem.4c00107","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00107https://doi.org/10.1021/acsearthspacechem.4c00107","url":null,"abstract":"<p >Naturally occurring bedded salt deposits are considered robust for the permanent disposal of heat-generating nuclear waste due to their unique physical and geological properties. The Brine Availability Test in Salt (BATS) is a US-DOE Office of Nuclear Energy funded project that uses heated borehole experiments underground (∼655 meters depth) at the Waste Isolation Pilot Plant (WIPP) in the bedded salt deposits of the Salado Formation to investigate the capacity for safe disposal of high-level, heat generating nuclear waste in salt. Uncertainties associated with brine mobility near heat-generating waste motivates the need to characterize the processes and sources of brine in salt deposits. Intragranular halite fluid inclusions are a potential source of brine that can migrate under temperature gradients toward heat sources. We developed a methodology to measure the stable isotopic compositions of water (δ<i>D</i>_VSMOW, δ¹⁸<i>O</i>_VSMOW) in brine from halite fluid inclusions using Cavity Ring-Down Spectroscopy that accounts for memory effects using a unique reference-sample-reference bracketing approach and that minimizes sample size requirements. We applied this approach to halite samples obtained from WIPP and compare these data to seeped brines collected from horizontal boreholes at WIPP after drilling at ambient conditions. The stable isotope compositions that we obtain for halite fluid inclusions (δ¹⁸<i>O</i>_VSMOW = +3.24 ± 0.53‰, δ<i>D</i>_VSMOW = −25.3 ± 5.1‰, ±1σ, <i>n</i> = 5) generally agree with previous measurements and likely reflect a combination of syn-depositional and/or postdepositional processes. The seep brines are isotopically distinct (δ¹⁸<i>O</i>_VSMOW = +3.46 ± 0.84‰, δ<i>D</i>_VSMOW = +7.3 ± 3.5‰, ±1σ, <i>n</i> = 35) and instead resemble evaporated seawater. We discuss our results in the context of prior WIPP-proximal waters and lay the groundwork for using stable isotopes of water in brine as a tool to assess the heat-induced mobilization of halite fluid inclusions in ongoing heating experiments that comprise the Brine Availability Test in Salt.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"16–30 16–30"},"PeriodicalIF":2.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143084766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measuring the Stable Isotope Composition of Water in Brine from Halite Fluid Inclusions and Borehole Brine Seeps Using Cavity Ring-Down Spectroscopy.","authors":"Daniel L Eldridge, Melissa M Mills, Hayden B D Miller, Shawn Otto, Jon E Davis, Eric J Guiltinan, Thom Rahn, Kristopher L Kuhlman, Philip H Stauffer","doi":"10.1021/acsearthspacechem.4c00107","DOIUrl":"10.1021/acsearthspacechem.4c00107","url":null,"abstract":"<p><p>Naturally occurring bedded salt deposits are considered robust for the permanent disposal of heat-generating nuclear waste due to their unique physical and geological properties. The Brine Availability Test in Salt (BATS) is a US-DOE Office of Nuclear Energy funded project that uses heated borehole experiments underground (∼655 meters depth) at the Waste Isolation Pilot Plant (WIPP) in the bedded salt deposits of the Salado Formation to investigate the capacity for safe disposal of high-level, heat generating nuclear waste in salt. Uncertainties associated with brine mobility near heat-generating waste motivates the need to characterize the processes and sources of brine in salt deposits. Intragranular halite fluid inclusions are a potential source of brine that can migrate under temperature gradients toward heat sources. We developed a methodology to measure the stable isotopic compositions of water (δ<i>D</i> _VSMOW, δ¹⁸ <i>O</i> _VSMOW) in brine from halite fluid inclusions using Cavity Ring-Down Spectroscopy that accounts for memory effects using a unique reference-sample-reference bracketing approach and that minimizes sample size requirements. We applied this approach to halite samples obtained from WIPP and compare these data to seeped brines collected from horizontal boreholes at WIPP after drilling at ambient conditions. The stable isotope compositions that we obtain for halite fluid inclusions (δ¹⁸ <i>O</i> _VSMOW = +3.24 ± 0.53‰, δ<i>D</i> _VSMOW = -25.3 ± 5.1‰, ±1σ, <i>n</i> = 5) generally agree with previous measurements and likely reflect a combination of syn-depositional and/or postdepositional processes. The seep brines are isotopically distinct (δ¹⁸ <i>O</i> _VSMOW = +3.46 ± 0.84‰, δ<i>D</i> _VSMOW = +7.3 ± 3.5‰, ±1σ, <i>n</i> = 35) and instead resemble evaporated seawater. We discuss our results in the context of prior WIPP-proximal waters and lay the groundwork for using stable isotopes of water in brine as a tool to assess the heat-induced mobilization of halite fluid inclusions in ongoing heating experiments that comprise the Brine Availability Test in Salt.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"16-30"},"PeriodicalIF":2.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11745166/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142996039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vibrational and Electronic Spectroscopy of 2-Cyanoindene Cations","authors":"Thomas E. Douglas-Walker,&nbsp;Eleanor K. Ashworth,&nbsp;Mark H. Stockett,&nbsp;Francis C. Daly,&nbsp;Isabelle Chambrier,&nbsp;Vincent J. Esposito,&nbsp;Marius Gerlach,&nbsp;Angel Zheng,&nbsp;Julianna Palotás,&nbsp;Andrew N. Cammidge,&nbsp;Ewen K. Campbell,&nbsp;Sandra Brünken and James N. Bull*,&nbsp;","doi":"10.1021/acsearthspacechem.4c0027010.1021/acsearthspacechem.4c00270","DOIUrl":"https://doi.org/10.1021/acsearthspacechem.4c00270https://doi.org/10.1021/acsearthspacechem.4c00270","url":null,"abstract":"<p >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 <i>D</i>₂ ← <i>D</i>₀ 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 μm), which may contribute to a broad plateau of CN-stretching modes across astronomical aromatic infrared band spectra. However, the activity of this mode is suppressed in the dehydrogenated (closed shell) cation, [2CNI-H]⁺. The IR spectral frequencies are modeled by anharmonic calculations at the B3LYP/N07D level of theory that include resonance polyad matrices, demonstrating that the CN-stretch mode remains challenging to describe with theory. The <i>D</i>₂ ← <i>D</i>₀ electronic transition of 2CNI⁺, which is origin dominated, occurs at 16,549 ± 5 cm^–1 in vacuum (6041.8 Å in air). There are no correspondences with reported diffuse interstellar bands.</p>","PeriodicalId":15,"journal":{"name":"ACS Earth and Space Chemistry","volume":"9 1","pages":"134–145 134–145"},"PeriodicalIF":2.9,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acsearthspacechem.4c00270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143084609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}