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Tailoring On-Surface Molecular Reactions and Assembly through Hydrogen-Modified Synthesis: From Triarylamine Monomer to 2D Covalent Organic Framework

arXiv

引用

arXiv 2022年

作者： Enderson, Zachery A. Murali, Harshavardhan Dasari, Raghunath R. Dai, Qingqing Li, Hong Parker, Timothy C. Brédas, Jean-Luc Marder, Seth R. First, Phillip N. School of Physics Georgia Institute of Technology AtlantaGA30332 United States School of Chemistry and Biochemistry Georgia Institute of Technology AtlantaGA30332 United States Department of Chemistry and Biochemistry The University of Arizona TucsonAZ85721 United States University of Colorado Boulder Renewable and Sustainable Energy Institute Department of Chemical and Biological Engineering Department of Chemistry Materials Science and Engineering Program BoulderCO80303 United States National Renewable Energy Laboratory Chemistry and Nanoscience Center GoldenCO80401 United States

Relative to conventional wet-chemical synthesis techniques, on-surface synthesis of organic networks in ultrahigh vacuum has few control parameters. The molecular deposition rate and substrate temperature are typically the only synthesis variables to be adjusted dynamically. Here we demonstrate that reducing conditions in the vacuum environment can be created and controlled without dedicated sources—relying only on backfilled hydrogen gas and ion gauge filaments—and can dramatically influence the Ullmann-like on-surface reaction used for synthesizing two-dimensional covalent organic frameworks (2D COFs). Using tribromo dimethylmethylene-bridged triphenylamine ((Br3)DTPA) as monomer precursors, we find that atomic hydrogen (H∙) blocks aryl-aryl bond formation to such an extent that we suspect this reaction may be a factor in limiting the ultimate size of 2D COFs created through on-surface synthesis. Conversely, we show that control of the relative monomer and hydrogen fluxes can be used to produce large self-assembled islands of monomers, dimers, or macrocycle hexamers, which are of interest in their own right. On-surface synthesis of oligomers, from a single precursor, circumvents potential challenges with their protracted wet-chemical synthesis and with multiple deposition sources. Using scanning tunneling microscopy and spectroscopy (STM/STS), we show that changes in the electronic states through this oligomer sequence provide an insightful view of the 2D-COF (synthesized in the absence of atomic hydrogen) as the endpoint in an evolution of electronic structures from the monomer. © 2022, CC BY-NC-SA.

关键词： Monomers

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A Four-Coordinate Pr4+Imidophosphorane Complex

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Angewandte Chemie 2024年第43期136卷

作者： Dr. Andrew C. Boggiano Dr. Sabyasachi Roy Chowdhury Dr. Michael D. Roy Dr. Maximilian G. Bernbeck Dr. Samuel M. Greer Prof. Bess Vlaisavljevich Prof. Henry S. La Pierre School of Chemistry & Biochemistry Georgia Institute of Technology Atlanta GA 30332-0400 USA Department of Chemistry University of South Dakota Vermillion SD 57069 USA Chemistry Division Los Alamos National Laboratory Los Alamos NM 87545 USA Nuclear and Radiological Engineering and Medical Physics Program School of Mechanical Engineering Georgia Institute of Technology Atlanta GA 30332-0400 USA

The imidophosphorane ligand, [NP t Bu 3 ] − ( t Bu= tert -butyl), enables isolation of a pseudo-tetrahedral, tetravalent praseodymium complex, [Pr 4+ (NP t Bu 3 ) 4 ] ( 1-Pr ), which is characterized by a suite of physical characterization methods including single-crystal X-ray diffraction, electron paramagnetic resonance, and L 3 -edge X-ray near-edge spectroscopies. Variable-temperature direct-current magnetic susceptibility data, supported by multiconfigurational quantum chemical calculations, demonstrate that the electronic structure diverges from the isoelectronic Ce 3+ analogue, driven by increased crystal field. The four-coordinate environment around Pr 4+ in 1-Pr , which is unparalleled in reported extended solid systems, provides a unique opportunity to study the interplay between crystal field splitting and spin-orbit coupling in a molecular tetravalent lanthanide within a pseudo-tetrahedral coordination geometry.

关键词： Imidophosphoranes Lanthanides Praseodymium Tetravalent lanthanide complexes

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Spatiotemporal Characterization of Simulated High-Intensity Optical Vortices

Spatiotemporal Characterization of Simulated High-Intensity ...

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Laser Science, LS 2021 - Part of Frontiers in Optics, FiO 2021

作者： Grace, Elizabeth Ma, Tammy Mariscal, Derek Djordjevic, Blagoje Kim, Joohwan Guang, Zhe Hakimi, Sahel Longman, Andrew Obst-Huebl, Lieselotte Ostermayr, Tobias Simpson, Raspberry Swanson, Kelly Scott, Graeme Tsai, Hai-En Zeraouli, Ghassan Geddes, Cameron Wilks, Scott Trebino, Rick Physics Department Georgia Institute of Technology AtlantaGA30332 United States Lawrence Livermore National Laboratory LivermoreCA94550 United States Mechanical and Aerospace Engineering University of California La Jolla San DiegoCA92093 United States Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Department of Nuclear Science and Engineering Massachusetts Institute of Technology CambridgeMA02139 United States Electrical and Computer Engineering Colorado State University Fort Collins CO80523 United States

This work examines pulses with orbital angular momentum and simulates the characterization of these pulses using STRIPED FISH, which correctly retrieves optical vortices and can be leveraged to provide deeper insight ... 详细信息

ISBN: (纸本)9781557528209

关键词： Laser produced plasmas

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Visualizing Field-free Deterministic Magnetic Switching of all–van der Waals Spin-Orbit Torque System Using Spin Ensembles in Hexagonal Boron Nitride

arXiv

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arXiv 2025年

作者： Zhang, Xi Zhou, Jingcheng Hu, Chaowei Deng, Kuangyin Wang, Chuangtang Agarwal, Nishkarsh Jin, Hanshang Al-Matouq, Faris A. Xu, Stelo Trivedi, Roshan S. Li, Senlei Rathi, Sumedh Lu, Hanyi Jiang, Zhigang Taufour, Valentin Hovden, Robert Zhao, Liuyan Cheng, Ran Xu, Xiaodong Chu, Jiun-Haw Du, Chunhui Rita Wang, Hailong School of Physics Georgia Institute of Technology AtlantaGA30332 United States Department of Physics University of Washington SeattleWA98105 United States Department of Electrical and Computer Engineering University of California RiversideCA92521 United States Department of Physics University of Michigan Ann ArborMI48109 United States Department of Materials Science and Engineering University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California DavisCA95616 United States Department of Physics University of California San Diego La Jolla CA92093 United States Applied Physics Program University of Michigan Ann ArborMI48109 United States Department of Physics and Astronomy University of California RiversideCA92521 United States Department of Materials Science and Engineering University of Washington SeattleWA98105 United States

Recently, optically active spin defects embedded in van der Waals (vdW) crystals have emerged as a transformative quantum sensing platform to explore cutting-edge materials science and quantum physics. Taking advantage of excellent solid-state integrability, this new class of spin defects can be arranged in controllable nanoscale proximity of target materials in vdW heterostructures, showing great promise for improving spatial resolution and field sensitivity of current sensing technologies. Building on this state-of-the-art measurement platform, here we report hexagonal boron nitride-based quantum imaging of field-free deterministic magnetic switching of room-temperature two-dimensional magnet Fe3GaTe2 in an all-vdW spin-orbit torque (SOT) system. By visualizing SOT-driven variations of nanoscale Fe3GaTe2 magnetic stray field profile under different conditions, we have revealed how the observed magnetic switching evolves from deterministic to indeterministic behavior due to the interplay between out-of-plane spins, in-plane spins and Joule heating. This understanding, which is otherwise difficult to access by conventional transport measurements, offers valuable insights on material design, testing, and evaluation of next-generation vdW spintronic devices. Copyright © 2025, The Authors. All rights reserved.

关键词： Van der Waals forces

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Divergent Stabilities of Tetravalent Cerium, Uranium, and Neptunium Imidophosphorane Complexes**

引用

Angewandte Chemie 2023年第34期135卷

作者： Kaitlyn S. Otte Dr. Julie E. Niklas Chad M. Studvick Andrew C. Boggiano Dr. John Bacsa Prof. Ivan A. Popov Prof. Henry S. La Pierre School of Chemistry and Biochemistry Georgia Institute of Technology Atlanta GA 30332-0400 USA Department of Chemistry The University of Akron Akron OH 44325-3601 USA Nuclear and Radiological Engineering Program Georgia Institute of Technology Atlanta GA 30332-0400 USA

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Final Measurement of the U235 Antineutrino Energy Spectrum with the PROSPECT-I Detector at HFIR

引用

Physical Review Letters 2023年第2期131卷 021802-021802页

作者： M. Andriamirado A. B. Balantekin C. D. Bass D. E. Bergeron E. P. Bernard N. S. Bowden C. D. Bryan R. Carr T. Classen A. J. Conant G. Deichert A. Delgado M. V. Diwan M. J. Dolinski A. Erickson B. T. Foust J. K. Gaison A. Galindo-Uribari C. E. Gilbert S. Gokhale C. Grant S. Hans A. B. Hansell K. M. Heeger B. Heffron D. E. Jaffe S. Jayakumar X. Ji D. C. Jones J. Koblanski P. Kunkle O. Kyzylova D. LaBelle C. E. Lane T. J. Langford J. LaRosa B. R. Littlejohn X. Lu J. Maricic M. P. Mendenhall A. M. Meyer R. Milincic P. E. Mueller H. P. Mumm J. Napolitano R. Neilson J. A. Nikkel S. Nour J. L. Palomino Gallo D. A. Pushin X. Qian C. Roca R. Rosero M. Searles P. T. Surukuchi F. Sutanto M. A. Tyra D. Venegas-Vargas P. B. Weatherly J. Wilhelmi A. Woolverton M. Yeh C. Zhang X. Zhang Department of Physics Illinois Institute of Technology Chicago Illinois 60616 USA Department of Physics University of Wisconsin Madison Wisconsin 53706 USA Department of Physics Le Moyne College Syracuse New York 13214 USA National Institute of Standards and Technology Gaithersburg Maryland 20899 USA Nuclear and Chemical Sciences Division Lawrence Livermore National Laboratory Livermore California 94550 USA High Flux Isotope Reactor Oak Ridge National Laboratory Oak Ridge Tennessee USA Department of Physics United States Naval Academy Annapolis Maryland 21402 USA Physics Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Brookhaven National Laboratory Upton New York 11973 USA Department of Physics Drexel University Philadelphia PA 19104-2875 Pennsylvania USA George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Atlanta Georgia 30332 USA Wright Laboratory Department of Physics Yale University New Haven Connecticut 06520 USA Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37916 USA Department of Physics Boston University Boston Massachusetts 02215 USA Department of Physics Susquehanna University Selinsgrove Pennsylvania 17870 USA Department of Physics (035-08) Temple University 1925 N 12th Street Philadelphia Pennsylvania 19122-1801 USA Department of Physics and Astronomy University of Hawaii Honolulu Hawaii 96822 USA Institute for Quantum Computing and Department of Physics University of Waterloo Waterloo ON N2L 3G1 Ontario Canada

This Letter reports one of the most precise measurements to date of the antineutrino spectrum from a purely U235-fueled reactor, made with the final dataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By extracting information from previously unused detector segments, this analysis effectively doubles the statistics of the previous PROSPECT measurement. The reconstructed energy spectrum is unfolded into antineutrino energy and compared with both the Huber-Mueller model and a spectrum from a commercial reactor burning multiple fuel isotopes. A local excess over the model is observed in the 5–7 MeV energy region. Comparison of the PROSPECT results with those from commercial reactors provides new constraints on the origin of this excess, disfavoring at 2.0 and 3.7 standard deviations the hypotheses that antineutrinos from U235 are solely responsible and noncontributors to the excess observed at commercial reactors, respectively.

关键词： Fission Neutrino interactions nuclear reactors Neutrinos Neutrino detectors Scintillators

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Final Search for Short-Baseline Neutrino Oscillations with the PROSPECT-I Detector at HFIR

arXiv

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arXiv 2024年

作者： Andriamirado, M. Balantekin, A.B. Bass, C.D. Rodrigues, O. Benevides Bernard, E.P. Bowden, N.S. Bryan, C.D. Carr, R. Classen, T. Conant, A.J. Deichert, G. Dolinski, M.J. Erickson, A. Galindo-Uribari, A. Gokhale, S. Grant, C. Hans, S. Hansell, A.B. Heeger, K.M. Heffron, B. Jaffe, D.E. Jayakumar, S. Koblanski, J. Kunkle, P. Lane, C.E. Littlejohn, B.R. Sanchez, A. Lozano Lu, X. Machado, F. Maricic, J. Mendenhall, M.P. Meyer, A.M. Milincic, R. Mueller, P.E. Mumm, H.P. Neilson, R. Qian, X. Roca, C. Rosero, R. Surukuchi, P.T. Sutanto, F. Venegas-Vargas, D. Weatherly, P.B. Wilhelmi, J. Yeh, M. Zhang, C. Zhang, X. Department of Physics Boston University BostonMA United States Brookhaven National Laboratory UptonNY United States Department of Physics Drexel University PhiladelphiaPA United States George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology AtlantaGA United States Department of Physics and Astronomy University of Hawaii HonoluluHI United States Department of Physics Illinois Institute of Technology ChicagoIL United States Nuclear and Chemical Sciences Division Lawrence Livermore National Laboratory LivermoreCA United States Department of Physics Le Moyne College SyracuseNY United States National Institute of Standards and Technology GaithersburgMD United States High Flux Isotope Reactor Oak Ridge National Laboratory Oak RidgeTN United States Physics Division Oak Ridge National Laboratory Oak RidgeTN United States Department of Physics Susquehanna University SelinsgrovePA United States Department of Physics United States Naval Academy AnnapolisMD United States Department of Physics University of Wisconsin MadisonWI United States

The PROSPECT experiment is designed to perform precise searches for antineutrino disappearance at short distances (7 – 9 m) from compact nuclear reactor cores. This Letter reports results from a new neutrino oscillation analysis performed using the complete data sample from the PROSPECT-I detector operated at the High Flux Isotope Reactor in 2018. The analysis uses a multi-period selection of inverse beta decay neutrino interactions with reduced backgrounds and enhanced statistical power to set limits on electron-flavor disappearance caused by mixing with sterile neutrinos with 0.2 – 20 eV2 mass splittings. Inverse beta decay positron energy spectra from six different reactor-detector distance ranges are found to be statistically consistent with one another, as would be expected in the absence of sterile neutrino oscillations. The data excludes at 95% confidence level the existence of sterile neutrinos in regions above 3 eV2 previously unexplored by terrestrial experiments, including all space below 10 eV2 suggested by the recently strengthened Gallium Anomaly. The best-fit point of the Neutrino-4 reactor experiment’s claimed observation of short-baseline oscillation is ruled out at more than five standard deviations. Copyright © 2024, The Authors. All rights reserved.

关键词： Neutrons

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Remote Monitoring of Molten Radioactive Glass

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MRS Online Proceedings Library 2020年第1期257卷 207-215页

作者： Alfred Schneider Kang-Wen K. Li Ray F. Schumacher Department of Nuclear Engineering 24-109B Massachusetts Institute of Technology Cambridge USA Georgia Institute of Technology Nuclear Engineering Program Atlanta USA Savannah River Laboratory Westinghouse Savannah River Company Aiken USA

An on-line method is described for the near-continuous monitoring of the composition of a molten radioactive waste glass or, alternatively, for signaling a deviation from the target composition of a waste glass. The principle of this method, proposed by A. Schneider in 1986, is founded on the relation between two specific physical properties and composition in a ternary system. Most glasses currently considered as waste forms can be represented as pseudo-ternary systems. The pair of properties especially well suited for this purpose are the viscosity and density of the molten glass. A novel viscometry method was developed which uses the remotely determined rise velocity of carefully metered gas bubbles. The monitoring method was tested successfully with simulated Savannah River waste glasses. An integrated probe was conceived for a Joule-heated melter for the on-line determination of viscosity, temperature, density, and liquid level. A computer program calculates the glass composition from the measured data, using information from a previously developed data base.

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Machine Learning for Single-Ended Event Reconstruction in PROSPECT Experiment

arXiv

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arXiv 2025年

作者： Andriamirado, M. Balantekin, A.B. Bass, C.D. Rodrigues, O. Benevides Bernard, E.P. Bowden, N.S. Bryan, C.D. Carr, R. Classen, T. Conant, A.J. Deichert, G. Delgado, A. Dolinski, M.J. Erickson, A. Fuller, M. Galindo-Uribarri, A. Gokhale, S. Grant, C. Hans, S. Hansell, A.B. Haugen, T.E. Heeger, K.M. Heffron, B. Jaffe, D.E. Jayakumar, S. Koblanski, J. Kunkle, P. Lane, C.E. Littlejohn, B.R. Sanchez, A. Lozano Lu, X. Machado, F. Maricic, J. Mendenhall, M.P. Meyer, A.M. Milincic, R. Mueller, P.E. Mumm, H.P. Neilson, R. Roca, C. Rosero, R. Venegas-Vargas, D. Wilhelmi, J. Yeh, M. Zhang, C. Zhang, X. Department of Physics Boston University BostonMA United States Brookhaven National Laboratory UptonNY United States Department of Physics Drexel University PhiladelphiaPA United States George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology AtlantaGA United States Department of Physics and Astronomy University of Hawaii HonoluluHI United States Department of Physics Illinois Institute of Technology ChicagoIL United States Nuclear and Chemical Sciences Division Lawrence Livermore National Laboratory LivermoreCA United States Department of Physics Le Moyne College SyracuseNY United States National Institute of Standards and Technology GaithersburgMD United States High Flux Isotope Reactor Oak Ridge National Laboratory Oak RidgeTN United States Physics Division Oak Ridge National Laboratory Oak RidgeTN United States Department of Physics Susquehanna University SelinsgrovePA United States Department of Physics and Astronomy University of Tennessee KnoxvilleTN United States Department of Physics United States Naval Academy AnnapolisMD United States Department of Physics University of Wisconsin MadisonWI United States Wright Laboratory Department of Physics Yale University New HavenCT United States

The Precision Reactor Oscillation and Spectrum Experiment, PROSPECT, was a segmented antineutrino detector that successfully operated at the High Flux Isotope Reactor in Oak Ridge, TN, during its 2018 run. Despite challenges with photomultiplier tube base failures affecting some segments, innovative machine learning approaches were employed to perform position and energy reconstruction, and particle classification. This work highlights the effectiveness of convolutional neural networks and graph convolutional networks in enhancing data analysis. By leveraging these techniques, a 3.3% increase in effective statistics was achieved compared to traditional methods, showcasing their potential to improve performance. Furthermore, these machine learning methodologies offer promising applications for other segmented particle detectors, underscoring their versatility and impact. Copyright © 2025, The Authors. All rights reserved.

关键词： Convolutional neural networks

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Correction to: Multistate and functional protein design using RoseTTAFold sequence space diffusion (Nature Biotechnology, (2024), 10.1038/s41587-024-02395-w)

引用

Nature Biotechnology 2024年

作者： Lisanza, Sidney Lyayuga Gershon, Jacob Merle Tipps, Samuel W. K. Sims, Jeremiah Nelson Arnoldt, Lucas Hendel, Samuel J. Simma, Miriam K. Liu, Ge Yase, Muna Wu, Hongwei Tharp, Claire D. Li, Xinting Kang, Alex Brackenbrough, Evans Bera, Asim K. Gerben, Stacey Wittmann, Bruce J. McShan, Andrew C. Baker, David Department of Biochemistry University of Washington SeattleWA United States Institute for Protein Design University of Washington SeattleWA United States Graduate Program in Biological Physics Structure and Design University of Washington SeattleWA United States Department of Molecular Engineering University of Washington SeattleWA United States Molecular & amp Cellular Biology Medical Scientist Training Program University of Washington SeattleWA United States Faculty of Engineering Sciences Heidelberg University Heidelberg Germany School of Chemistry and Biochemistry Georgia Institute of Technology AtlantaGA United States Office of the Chief Scientific Officer Microsoft RedmondWA United States Howard Hughes Medical Institute University of Washington SeattleWA United States

Correction to: Nature Biotechnologyhttps://***/10.1038/s41587-024-02395-w, published online 25 September 2024. In the version of the article initially published, in the key to Fig. 2f the colors were swapped and have now been amended so that "W guidance" is purple and "Unconditional" is grey. In Fig. 5a, the color of "Child B" has been corrected from pink to purple, and in Fig. 5d, "β-helix" has now been amended to "β-sheet". These corrections have been made to the HTML and PDF versions of the article. © The Author(s) 2024.

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