Isotopic Abundance Research Articles

Nuclear Quadrupolar Resonance Structural Characterization of Halide Perovskites and Perovskitoids: A Roadmap from Electronic Structure Calculations for Lead-Iodide-Based Compounds.

Metal halide perovskites, including some of their related perovskitoid structures, form a semiconductor class of their own, which is arousing ever-growing interest from the scientific community. With halides being involved in the various structural arrangements, namely, pure corner-sharing MX6 (M is metal and X is halide) octahedra, for perovskite networks, or alternatively a combination of corner-, edge-, and/or face-sharing for related perovskitoids, they represent the ideal probe for characterizing the way octahedra are linked together. Well known for their inherently large quadrupolar constants, which is detrimental to the resolution of nuclear magnetic resonance spectroscopy, most abundant halide isotopes (35/37Cl, 79/81Br, 127I) are in turn attractive for magnetic field-free nuclear quadrupolar resonance (NQR) spectroscopy. Here, we investigate the possibility of exploiting NQR spectroscopy of halides to distinctively characterize the various metal halide structural arrangements, using density functional theory simulations. Our calculations nicely match the available experimental results. Furthermore, they demonstrate that compounds with different connectivities of their MX6 building blocks, including lower dimensionalities such as 2D networks, show distinct NQR signals in a broad spectral window. They finally provide a roadmap of the characteristic NQR frequency ranges for each octahedral connectivity, which may be a useful guide to experimentalists, considering the long acquisition procedures typical of NQR. We hope this work will encourage the incorporation of NQR spectroscopy to further our knowledge of the structural diversity of metal halides.

Investigation of Lane-consistent dispersive optical-model potential for <sup>208</sup>Pb

Lead is an important alloy material nuclide. And lead eutectic is also an important coolant, which is applied in the construction of Lead-cooled Fast Reactor such as The European Lead-cooled System (ELSY) and the China Lead-based Research reactor (CLEAR-I), as well as in research related to Generation-IV reactor. The study and calculation of lead nuclear data have important theoretical value and application prospects. <sup>208</sup>Pb is the most stable and abundant isotope in lead nuclei, and high quality description of <sup>208</sup>Pb nuclear scattering data is the key to achieving theoretical calculations of nuclear reaction data for lead nuclei. Based on the dispersive optical model, this work describes nucleon scattering on <sup>208</sup>Pb by using the dispersive optical potential. The dispersive optical model potential is defined by energy-dependent real potentials, imaginary potentials, the corresponding dispersive contributions to the real potential which are calculated analytically from the corresponding imaginary potentials by using a dispersion relation, and isospin dependence is reasonably considered by introducing isovector component (i.e. Lane term) in the potential depth constants of the real Hartree-Fock potential <i>V</i><sub>HF</sub> and the surface imaginary potential <i>W</i><sub>s</sub>. Unlike K-D potential, which requires two different sets of parameters to describe neutron and proton induced scattering data, this optical potential uses the same set of parameters to simultaneously describe nucleon-nucleus scattering data. The derived potential in this work shows a very good description of nucleon-nucleus scattering data on <sup>208</sup>Pb up to 200 MeV. Calculated neutron total cross sections, neutron and proton elastic scattering angular distributions, as well as neutron and proton elastic analyzing powers are shown to be in good agreement with experimental data. Additionally, the difference in potential between the neutron and protons induced is described by the isovector term, a reasonable good prediction of quasielastic (p, n) scattering data is achieved.

Sulfur isotope engineering in heterostructures of transition metal dichalcogenides.

Heterostructuring of two-dimensional materials offers a robust platform to precisely tune optoelectronic properties through interlayer interactions. Here we achieved a strong interlayer coupling in a double-layered heterostructure of sulfur isotope-modified adjacent MoS2 monolayers via two-step chemical vapor deposition growth. The strong interlayer coupling in the MoS2(34S)/MoS2(32S) was affirmed by low-frequency shear and breathing modes in the Raman spectra. The photoluminescence emission spectra showed that isotope-induced changes in the electronic structure and strong interlayer coupling led to the suppression of intralayer excitons, resulting in dominant emission from the MoS2(32S) layer. Time-resolved photoluminescence experiments indicated faster lifetimes in the MoS2(34S)/MoS2(32S) heterostructure compared to the conventional bilayers with the natural isotopic abundance, highlighting nuanced interlayer exciton dynamics due to the isotopic modification. This study underscores the great potential of isotope engineering in van der Waals heterostructures, as it enables tailoring the band structure and exciton dynamics at the nuclear level without the need of chemical modification.

Combining the 15N Gas Flux Method and N2O Isotopocule Data for the Determination of Soil Microbial N2O Sources.

The analysis of natural abundance isotopes in biogenic N2O molecules provides valuable insights into the nature of their precursors and their role in biogeochemical cycles. However, current methodologies (for example, the isotopocule map approach) face limitations, as they only enable the estimation of combined contributions from multiple processes at once rather than discriminating individual sources. This study aimed to overcome this challenge by developing a novel methodology for the partitioning of N2O sources in soil, combining natural abundance isotopes and the use of a 15N tracer (15N Gas Flux method) in parallel incubations. Laboratory incubations of an agricultural soil were conducted to optimize denitrification conditions through increased moisture and nitrate amendments, using nitrate that was either 15N-labeled or unlabeled. A new linear system combined with Monte Carlo simulation was developed to determine N2O source contributions, and the subsequent results were compared with FRAME, a Bayesian statistical model for stable isotope analysis. Our new methodology identified bacterial denitrification as the dominant process (87.6%), followed by fungal denitrification (9.4%), nitrification (1.5%), and nitrifier denitrification (1.6%). Comparisons with FRAME showed good agreement, although FRAME estimated slightly lower bacterial denitrification (80%) and higher nitrifier-denitrification (9%) contributions. This approach provides an improved framework for accurately partitioning N2O sources, enhancing understanding of nitrogen cycling in agroecosystems, and supporting broader environmental applications.

In Situ Vivianite Formation in Intertidal Sediments: Ferrihydrite-Adsorbed P Triggers Vivianite Formation.

Coastal sediments are a key contributor to oceanic phosphorus (P) removal, impacting P bioavailability and primary productivity. Vivianite, an Fe(II)-phosphate mineral, can be a major P sink in nonsulfidic, reducing coastal sediments. Despite its importance, vivianite formation processes in sediments remain poorly understood. Here, we applied a novel approach to detect and quantify in situ vivianite formation in three intertidal flats. We conducted 7-week long incubations of mesh-bags filled with sediments mixed with (1) 57Fe-ferrihydrite, (2) 57Fe-ferrihydrite with adsorbed phosphate, and (3) 57Fe-ferrihydrite with adsorbed phosphate and some vivianite (natural Fe isotope abundance), which could serve as crystal growth sites. Synthesizing the ferrihydrite from 57Fe (96.1%) enabled us to detect transformation products using 57Fe-Mössbauer spectroscopy. Vivianite formed only in treatments containing adsorbed phosphate and only at the two sites where vivianite formation was thermodynamically feasible based on porewater chemistry. These results demonstrate vivianite formation within weeks when locally favorable Fe:P ratios exist. Although vivianite comprised a minor fraction of Fe (up to 15%), it represented a significant P pool (up to 72%), emphasizing its role in coastal P burial. Additionally, our results may apply to other environmental systems like limnic sediments.

Analysis of Major Chemical Constituents in Jiuwei Decoction Based On Capillary Electrophoresis Coupled With Quadrupole Time‐of‐Flight Mass Spectrometry

ABSTRACTAn analytical method for identifying the chemical constituents in the Chinese herbal combination Jiuwei decoction was established using capillary electrophoresis coupled with quadrupole time‐of‐flight mass spectrometry. Nine herbs were extracted with a 60:40 (v/v) ethanol/water solution to prepare the Jiuwei decoction. Electrophoretic separation was carried out using a 50 µm i.d., 125 cm bare fused silica capillary at a constant temperature of 25°C for sample injection. The chemical composition was analyzed and identified in both positive and negative ion modes. In the positive separation mode, a separation voltage of 30 kV was applied, with a 1% aqueous formic acid solution serving as the background electrolyte (BGE), along with a 50:50 (v/v) methanol/water solution containing 0.1% formic acid as the sheath liquid. In the negative separation mode, a separation voltage of −30 kV was employed, utilizing a 50 mM ammonium acetate solution (pH 9.0) as the BGE, combined with a 50:50 (v/v) methanol/water solution containing 5 mM ammonium acetate as the sheath liquid. The MassHunter Qualitative Analysis software (version 10.0) was utilized to identify 52 compounds based on accurate mass, isotope abundance, isotopic patterns, and fragmentation information. The data were compared with the Agilent Personal Compound Database and Library of traditional Chinese medicine (TCM), as well as multiple online databases (TCMSP, ChemSpider, PubChem, PubMed, and Web of Science) and relevant literature. The fragmentation pathways of representative compounds were also characterized. This study identified the chemical composition of Jiuwei decoction, providing a molecular basis for further exploration of its pharmacological effects and presenting a robust methodology for the compositional analysis of complex TCM mixtures.

Performance Optimization of a Large Geometry High Resolution-Secondary Ion Mass Spectrometer (HR-SIMS) for High Precision Measurements of Oxygen Isotopic Composition (δ18O) and U-Pb Geochronology in Zircon.

A large geometry high resolution secondary ion mass spectrometer (HR-SIMS) has been established as a part of the National Geochronology Facility (NGF) at Inter-University Accelerator Centre (IUAC), New Delhi. The performance of the instrument related to high spatial resolution, high mass resolving power (MRP), sensitivity of the instrument to measure low abundant isotopes, and sensitivity of the instrument for 206Pb signal under different conditions are optimized and presented in this paper. We report the precision of the order of ~ 0.2‰ for oxygen isotopes measurement in 91500 reference material zircon and measured δ18O value of 10.08‰ ± 0.18‰ (2SD), which is in agreement with the recommended values. For U-Pb age measurement in zircon, Plešovice and FCT reference materials are measured as unknown and their 206Pb/238U ages agree with the reported values within the uncertainties. A long-term evaluation of 206Pb/238UO and 206Pb/238U isotopic measurement ratio is also presented.

Nitrite Cycling in Freshwater Ecosystems: A Case Study of an Artificial Reservoir in Eastern China Using Nitrite Dual Isotopes Combined with a Geochemical Model

Reservoirs are hotspots for emissions of the greenhouse gas nitrous oxide; however, the nitrite cycling processes associated with nitrous oxide production therein remain poorly understood, limiting a better assessment of the potential for reservoirs to emit nitrous oxide. Accordingly, this study presents the application of the natural abundance isotope technique combined with a geochemical model to elucidate the nitrite cycling in the freshwater aquaculture and non-aquaculture zones of a large artificial reservoir in eastern China. We employed nitrite dual isotopes to identify nitrite transformation processes. Additionally, a steady-state model was used to estimate the rates of these processes as well as the residence time of nitrite. Our findings indicate that nitrite production in this reservoir may be primarily driven by ammonia oxidation. However, the pathways of nitrite removal differ notably between the aquaculture and non-aquaculture zones, suggesting a significant impact of the aquaculture activities. The steady-state model calculations revealed that nitrification may be more pronounced in the aquaculture zones compared to the non-aquaculture zones, which may be related to the altered balance of competition for substrates between phytoplankton and microbes induced by aquaculture activities. Moreover, we observed a latitude-dependent increase in the significance of nitrite oxidation in natural environments, highlighting potential implications for regional and global nitrogen cycling. Our study highlights the complexity of the nitrite cycle and emphasizes the roles of both natural and anthropogenic factors in shaping nitrogen dynamics within freshwater reservoirs. This understanding contributes to a more accurate assessment of the greenhouse gas emission potential of reservoirs, offering valuable implications for the adoption of sustainable aquaculture practices to mitigate climate impacts and support global sustainable development goals.

Deep Nitrogen Fluxes and Sources Constrained by Arc Lava Phenocrysts

AbstractNitrogen (N) dominates Earth's atmosphere (78% N2) but occurs in trace abundances in silicate minerals, making it a sensitive tracer of recycled surface materials into the mantle. The mechanisms controlling N transfer between terrestrial reservoirs remain uncertain because low N abundances in mineral‐hosted fluid inclusions (FIs) are difficult to measure. Using new techniques, we analyzed N and He isotope compositions and abundances in olivine‐ and pyroxene‐hosted FIs from arc volcanoes in Southern Chile, Cascadia, Central America, and the Southern Marianas. These measurements enable an estimate of the global flux of N outgassing from arcs (4.0 × 1010 mol/yr). This suggests that Earth is currently in a state of net N ingassing, with roughly half of subducted N returned to the mantle. Additionally, the N outgassing flux of individual arcs correlates with the thickness of subducting pelagic sediment, suggesting that N cycling in the modern solid Earth is largely controlled by sediment subduction.

NIST Library Identification Probabilities Are the Highest with Cold EI Mass Spectra.

Cold EI improves all of the central GC-MS performance aspects, but even though it is known for providing enhanced molecular ions, it is important to realize that Cold EI mass spectra also include all of the standard EI fragment ions. Thus, Cold EI mass spectra are fully compatible with mass spectral libraries, such as NIST for sample identification. As a result, Cold EI mass spectra (unlike any other soft ionization method) provide highly effective identifications that are often better than those obtained with standard EI for a few reasons:1).Cold EI mass spectra with enhanced molecular ions typically provide higher identification probabilities than standard EI, even though scoring lower matching factors (false alternatives scores are lowered much more).2).The visually observed molecular ions further serve to confirm or reject the NIST library identifications.3).Molecular ions provide isotope abundances that serve with our TAMI software for automatic confirmation or rejection of the NIST library identification and provide an elemental formula in case the compound is not in the library.4).The Cold EI identification probability can be even higher than that of a mass spectrum with a perfect match of 999 that can be obtained by NIST library searching its own mass spectrum.5).The clear Cold EI molecular ion enables the use of the NIST library option of constraints search with the molecular ion that further significantly increases the identification probability. Our findings are demonstrated with mass spectra of hexadecane (n-C16H34), n-C40H82, pyrene, nitrobenzene, chlorpromazine, di-n-octyl phthalate, and deltamethrin.

Neutrino-driven core-collapse supernova yields in galactic chemical evolution

Abstract We provide yields from 189 neutrino-driven core-collapse supernova (CCSN) simulations covering zero-age main sequence masses between 11 and 75 M⊙ and three different metallicities. Our CCSN simulations have two main advantages compared to previous methods used for applications in Galactic chemical evolution (GCE). Firstly, the mass cut between remnant and ejecta evolves naturally. Secondly, the neutrino luminosities and thus the electron fraction are not modified. Both is key to obtain an accurate nucleosynthesis. We follow the composition with an in-situ nuclear reaction network including the 16 most abundant isotopes and use the yields as input in a GCE model of the Milky Way. We adopt a GCE which takes into account infall of gas as well as nucleosynthesis from a large variety of stellar sources. The GCE model is calibrated to reproduce the main features of the solar vicinity. For the CCSN models, we use different calibrations and propagate the uncertainty. We find a big impact of the CCSN yields on our GCE predictions. We compare the abundance ratios of C, O, Ne, Mg, Si, S, Ar, Ca, Ti, and Cr with respect to Fe to an observational data set as homogeneous as possible. From this, we conclude that at least half of the massive stars have to explode to match the observed abundance ratios. If the explosions are too energetic, the high amount of iron will suppress the abundance ratios. With this, we demonstrate how GCE models can be used to constrain the evolution and death of massive stars.

Expanding the Toolset of Biomolecular NMR with Efficient and Cost-Effective 17O-Labeling via Bacterial Expression.

Oxygen plays a central role in biomolecular structures and functions, with 17O NMR emerging as a powerful tool for elucidating biomolecular properties. However, the low natural abundance of the NMR-active isotope, 17O (0.0373 %), presents a significant hurdle to its widespread application. Here, we introduce a rapid and cost-effective approach for amino acid-specific 17O-labeling of recombinant proteins. Using a common bacterial expression system and with a 30-minute rapid synthesis protocol of 17O-labeled amino acids via mechanochemical saponification, we have generated Leu- and Phe-specific 17O-labeled recombinant proteins derived from diverse organisms, including CrgA and FtsQ from Mycobacterium tuberculosis and E protein from SARS-CoV-2 virus, demonstrating the applicability of our technique for amino acids known to be isotopically labeled without scrambling. We have acquired magic-angle-spinning 17O NMR of these proteins to confirm the successful 17O labeling and illustrate the sensitivity of 17O NMR to the protein's local structural environments. Our work significantly broadens the accessibility of 17O-NMR, empowering researchers to delve deeper into protein biophysics and biochemistry. This approach opens new avenues for understanding cellular processes at the molecular level by providing an effective tool for investigating oxygen-related interactions and chemistry within biomolecules.

Silicon Isotopic Composition of Mainstream Presolar SiC Grains Revisited: The Impact of Nuclear Reaction Rate Uncertainties

Abstract Presolar grains are stardust particles that condensed in the ejecta or in the outflows of dying stars and can today be extracted from meteorites. They recorded the nucleosynthetic fingerprint of their parent stars and thus serve as valuable probes of these astrophysical sites. The most common types of presolar silicon carbide grains (called mainstream SiC grains) condensed in the outflows of asymptotic giant branch stars. Their measured silicon isotopic abundances are not significantly influenced by nucleosynthesis within the parent star but rather represent the pristine stellar composition. Silicon isotopes can thus be used as a proxy for galactic chemical evolution (GCE). However, the measured correlation of 29Si/28Si versus 30Si/28Si does not agree with any current chemical evolution model. Here, we use a Monte Carlo model to vary nuclear reaction rates within their theoretical or experimental uncertainties and process them through stellar nucleosynthesis and GCE models to study the variation of silicon isotope abundances based on these nuclear reaction rate uncertainties. We find that these uncertainties can indeed be responsible for the discrepancy between measurements and models and that the slope of the silicon isotope correlation line measured in mainstream SiC grains agrees with chemical evolution models within the nuclear reaction rate uncertainties. Our result highlights the importance of future precision reaction rate measurements for resolving the apparent data–model discrepancy.

High-field SABRE pulse sequence design for chemically non-equivalent spin systems.

Signal amplification by reversible exchange (SABRE) employs the non-equilibrium spin order of parahydrogen as a source of strong nuclear magnetic resonance (NMR) signal enhancement, with the objective of increasing NMR sensitivity. In SABRE, a parahydrogen molecule and a substrate form a transient polarization transfer complex. Performed within the high magnetic field of an NMR spectrometer, SABRE enables the hyperpolarization of nuclear spins without additional polarizers. Nevertheless, it requires thorough pulse sequence design. The high-field polarization transfer strategy strongly depends on the type of the spin system formed by the parahydrogen-nascent protons in the SABRE complex: chemically equivalent or non-equivalent. SABRE hyperpolarization in chemically equivalent spin systems has been the subject of considerable attention, even after being relevant only for a limited number of substrates. Efficient hyperpolarization in chemically non-equivalent complexes remained a key challenge, hindering the full potential of high-field SABRE and the ability to polarize a broader range of SABRE substrates. This work reports the multinuclear 1H-15N pulse sequence for efficient 15N hyperpolarization in chemically non-equivalent SABRE complexes. This approach relies on the simultaneous 1H and 15N radiofrequency excitation of the complex-bound nuclei with weak continuous wave magnetic fields. The proposed pulse sequence enabled the hyperpolarization of the 15N nuclei in a mixture of the antimicrobial drugs containing a 5-nitroimidazol moiety at their natural 15N isotopic abundance (0.76% of 15N polarization). Furthermore, it permitted the precise assignment of the SABRE complexes responsible for the polarization transfer.

JOYS+ study of solid-state 12C/13C isotope ratios in protostellar envelopes

Context. The carbon isotope ratio is a powerful tool for studying the evolution of stellar systems due to its sensitivity to the local chemical environment. Recent detections of CO isotopologs in disks and exoplanet atmospheres revealed a high variability in the isotope abundance, ponting towards significant fractionation in these systems. In order to fully understand the evolution of this quantity in stellar and planetary systems, however, it is crucial to trace the isotope abundance from stellar nurseries to the time of planet formation. During the protostellar stage, the multiple vibrational modes of CO2 and CO ice, which peak in the near- and mid-infrared, provide a unique opportunity to examine the carbon isotope ratio in the solid state. With the current sensitivity and wide spectral coverage of the James Webb Space Telescope, the multiple weak and strong absorption features of CO2 and CO have become accessible at a high signal-to-noise ratio in solar-mass systems. Aims. We aim to study the carbon isotope ratio during the protostellar stage by deriving column densities and ratios from the various absorption bands of CO2 and CO ice, and by comparing our results with the ratios derived in other astronomical environments. Methods. We quantify the 12CO2/13CO2 and the 12CO/13CO isotope ratios in 17 class 0/I low-mass protostars from the 12CO2 ν1 + ν2 and 2ν1 + ν2 combination modes (2.70 µm and 2.77 µm), the 12CO2 ν3 stretching mode (4.27 µm), the 13CO2 ν3 stretching mode (4.39 µm), the 12CO2 ν2 bending mode (15.2 µm), the 12CO 1-0 stretching mode (4.67 µm), and the 13CO 1-0 stretching mode (4.78 µm) using the James Webb Space Telescope NIRSpec and MIRI observations. We also report a detection of the 2-0 overtone mode of 12CO at 2.35 µm. Results. The column densities and 12CO2/13CO2 ratios derived from the various CO2 vibrational modes agree within the reported uncertainties, and we find mean ratios of 85 ± 23, 76 ± 12, and 97 ± 17 for the 2.70 µm band, the 4.27 µm band, and the 15.2 µm band, respectively. The main source of uncertainty on the derived values stems from the error on the band strengths; the observational errors are negligible in comparison. Variation of the 12CO2/13CO2 ratio is observed from one source to the next, which indicates that the chemical conditions of their envelopes might be genuinely different. The 12CO/13CO ratios derived from the 4.67 µm band are consistent, albeit elevated with respect to the 12CO2/13CO2 ratios, and we find a mean ratio of 165 ± 52. Conclusions. These findings indicate that ices leave the prestellar stage with elevated carbon isotope ratios relative to the overall values found in the interstellar medium, and that fractionation becomes a significant factor during the later stages of star and planet formation.

Soil nitrogen biogeochemistry and hydrological characteristics shape the nitrate levels in a river.

The high levels of nitrate (NO3-) in the surface water have contributed to eutrophication and other eco-environmental damages worldwide. Although the excessive NO3- concentrations in rivers were often attributed to anthropogenic activities, some undisturbed or slightly disturbed rivers also had high NO3- levels. This study utilized multi-pronged approaches (i.e., river natural abundance isotopes, 15N-labeling techniques, and qPCR) to provide a comprehensive explanation of the reason for the high NO3- levels in a river draining forest-dominated terrene. The river natural abundance isotopes (δ15N/δ18O-NO3-) indicated that the soil source (i.e., soil organic nitrogen-SON and chemical fertilizer-CF) were the primary contributors to the NO3-, and the NO3- removal was probably prevalent in the basin scale. The 15N-labeling techniques quantitatively showed that denitrification and anammox were stronger than nitrification in the soils and sediments. Structural equation models suggested that nitrification in the soils was regulated by NH4+-N contents, which, in turn, were closely related to fertilization in spring. Denitrification and anammox were largely controlled by elevation and functional gene abundances (i.e., nirK and hzsB, respectively). The hydrological isotopes (i.e., δD/δ18O-H2O) indicated that the transport of NO3- from soil to the river was related to the intensity of runoff leaching to the soil, In contrast, the riverine NH4+ was largely from point sources; thus, increasing runoff led to a dilution effect. This study clearly showed that soil biogeochemistry and hydrological condition of a river basin jointly shaped the high NO3- levels in the almost undisturbed river.

Atomic Structure and Isotope Abundance: An Activity for General Chemistry

Atomic Structure and Isotope Abundance: An Activity for General Chemistry

TRENDS OF THE YEARS: SYSTEMATIC LITERATURE REVIEW ANALYSIS BASED ON THE METHODOLOGICAL PRINCIPLES OF THE ELECTROMIGRATION PROCESS

Green emerging technologies are needed for the growing global demand economy and to respond to environmental problems caused by industrialization. The most significant global issue is the transition from fossil fuel to sustainable green energy. Even if a high abundance of lithium isotopes means suitable materials for nuclear or electrical industries, the currently used method for producing lithium isotopes is associated with severe Hg environmental pollution. To achieve global targets assumed to mitigate climate change and environmental pollution, several attempts to find promising eco-friendly alternatives indicated electromigration separation as the most suitable method. Here, we applied a systematic literature synthesis using the PRISMA procedure to review peer-reviewed literature that focuses on the technologies and methodologies for the separation of 6Li and 7Li. Documents were extracted from Web of Science, Scopus, and Google Scholar databases and were subjected to quantitative and qualitative assessment based on co-occurrence analysis. We evaluated the limitations of existing methods and technologies, creating syntheses with characteristics and performances of the crown ethers used in the separation process. The progress in developing crown ethers with increased action capacity in the separation process of 6Li and 7Li ions was detailed. The main conclusion was that the analyzed methods are feasible for performing the process of separating the 6Li and 7Li isotopes, considering the limitation of solubility and the high cost of production.

Hyperfine structure of Lu I transition at 642 nm and its application to explore new odd parity autoionization resonances

Resonance ionization mass spectroscopy using three-step photoionization (PI) schemes was employed to study the 642 nm transition of Lu I. Multimode tunable dye lasers were used in these studies to confirm the transition and further characterization of its hitherto unreported hyperfine structure. The hyperfine features of less abundant isotope 176Lu and hyperfine A constant of upper level of 642 nm line and its transition isotope shift were determined for the first time. New autoionization resonances of odd parity connecting from the upper level of this transition were explored in the range 48315 – 50940 cm−1.

The ESO SupJup Survey. III. Confirmation of 13CO in YSES 1 b and Atmospheric Detection of YSES 1 c with CRIRES+

High-resolution spectroscopic characterization of young super-Jovian planets enables precise constraints on elemental and isotopic abundances of their atmospheres. As part of the ESO SupJup Survey, we present high-resolution spectral observations of two wide-orbit super-Jupiters in YSES 1 (or TYC 8998-760-1) using the upgraded VLT/CRIRES+ ( R∼100,000 ) in K-band. We carry out free atmospheric retrieval analyses to constrain chemical and isotopic abundances, temperature structures, rotation velocities ( vsini ), and radial velocities. We confirm the previous detection of 13CO in YSES 1 b at a higher significance of 12.6σ, but point to a higher 12CO/13CO ratio of 88 ± 13 (1σ confidence interval), consistent with the primary’s isotope ratio 66 ± 5. We retrieve a solar-like composition in YSES 1 b with a C/O = 0.57 ± 0.01, indicating a formation via gravitational instability or core accretion beyond the CO iceline. Additionally, the observations lead to detections of H2O and CO in the outer planet YSES 1 c at 7.3σ and 5.7σ, respectively. We constrain the atmospheric C/O ratio of YSES 1 c to be either solar or subsolar (C/O = 0.36 ± 0.15), indicating the accretion of oxygen-rich solids. The two companions have distinct vsini , 5.34 ± 0.14 km s−1 for YSES 1 b and 11.3 ± 2.1 km s−1 for YSES 1 c, despite their similar natal environments. This may indicate different spin axis inclinations or effective magnetic braking by the long-lived circumplanetary disk around YSES 1 b. YSES 1 represents an intriguing system for comparative studies of super-Jovian companions and linking present atmospheres to formation histories.