1. NSLS-II Friday Lunchtime Seminar

   "Structural studies of SARS-CoV-2 viral fusion inhibition peptides at NSLS-II"

   Presented by Dale Kreitler, NSLS-II

   Friday, November 20, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   SARS-CoV-2 uses a common viral strategy for fusing the viral envelope with a host cell membrane. The resulting fusion event is paramount to the infection process and this common strategy is known as a type I viral fusion mechanism. The energetically unfavorable membrane fusion event is driven by a large conformational change of the spike protein that occurs when the spike protein comes into contact with its target receptor on the host cell surface. One possible way to prevent this viral fusion event involves disrupting this conformational change by blocking the formation of the 6 helix bundle complex formed by the spike protein with synthetic polypeptide inhibitors. In this talk I will discuss preliminary structures of these polypeptide inhibitors in complex with fragments of the SARS-CoV-2 spike protein that were obtained at NSLS-II during min-safe operations. These structures provide some insight into important design considerations for future generation of SARS-CoV-2 membrane fusion inhibitors.
2. NSLS-II Friday Lunchtime Seminar

   "The role of hard X-ray synchrotron characterization of additively manufactured metal and composite structures: enhancing processes, materials and performance"

   Presented by Gary Halada, Stony Brook University, NY

   Friday, November 13, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   Focusing on current challenges in understanding the process/structure/properties/performance relationship in additively manufactured (3D printed) alloys and ceramics, this talk will outline the potential role of planned hard X-ray capabilities at NSLS II. In particular, the talk will include recent results from an ongoing study of the relationship of factors contributing to durability of laser powder bed fusion (LPDF) formed 316L stainless steel, the role of print-formed micro and nanostructural heterogeneities on surface and bulk properties, and recent X-ray studies of alloys designed for aerospace, energy infrastructure and biomedical applications. The potential for in situ and in operando studies of printing via laser melting/sintering and post-printing processing to decrease porosity, improve surface finish and mechanical properties, as well as in situ X-ray analysis during corrosion and thermomechanical testing, will enhance the value of AM for manufacturing and a wide variety of applications relevant to regional industry and commercial applications.
3. NSLS-II Friday Lunchtime Seminar

   "Investigation of Aqueous Electrochemical Energy Storage Mechanisms Utilizing Advanced Characterization Techniques"

   Presented by Daniel Charles, University of New Hampshire

   Friday, November 6, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   Electrochemical energy storage (EES) has become prevalent in daily life for their use in mobile electronics and electric vehicles. More recently, the need for large-scale stationary energy storage to integrate clean and renewable alternative energy sources to the electric grid has arisen. Aqueous EES devices using beyond-lithium charge carriers offer an attractive solution to this problem because of their superior safety, lower cost, and excellent transport properties compared to their organic counterparts. However, improvements in energy density and cyclability are required for implementation. Fundamental research on the charge-storage mechanisms is critical to understanding the structure-function relationship and, thus, for the development of electrodes materials for aqueous EES. Characterization of these electrode materials using synchrotron and neutron techniques provide vital information on the crystalline and electronic structure. Furthermore, time-resolved in situ measurements offer detailed information on structural changes due to the intercalation/de-intercalation of cations and the evolution of the electronic state of metal components during redox reactions. This, coupled with half-cell and full-cell electrochemical measurements, provides valuable insight into the change-storage mechanisms that occur. In this work, advanced characterization techniques have been used to investigate the charge storage mechanisms of nanoscale transition metal oxide electrode materials for aqueous EES. Various types of electrochemical charge storage mechanisms (pseudocapacitive, intercalation, and phase-change) were studied. Numerous strategies for improving the energy density and cyclability have been employed, including; studying the promotional effects of structural water, inducing structural disorder, synthesizing materials with open frameworks, doping with more redox-active components, using multivalent cations as charge carriers, and expanding the available potential window. These results provide a pathway for designing the next generation of aqueous EES devices. ________________________________ Daniel S Charles, Xiaoqiang Shan, SaeWon Kim, Fenghua Guo, and Xiaowei Teng
4. NSLS-II Friday Lunchtime Seminar

   "Understanding the Instability of the Halide Perovskite CsPbI3 Through Temperature-Dependent Structural Analysis"

   Presented by Daniel B Straus, Princeton University, NJ

   Friday, October 30, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   Daniel B. Straus, Shu Guo, AM Milinda Abeykoon, and R. J. Cava Despite the tremendous interest in halide perovskite solar cells, the structural reasons that cause the all-inorganic perovskite CsPbI3 to be unstable at room temperature remain mysterious especially since many tolerance factor-based approaches predict CsPbI3 should be stable as a perovskite. We use a solid-state method to synthesize single crystals of perovskite-phase CsPbI3 that are kinetically stable at room temperature, allowing us to characterize its bulk properties and rationalize its thermodynamic instability. Electronically, CsPbI3 does not behave like a conventional semiconductor because its optical absorption and joint density-of-states is greatest near the band edge and decreases beyond the band gap for at least 1.9 eV. Structurally, single-crystal X-ray diffraction measurements reveal that while Cs occupies a single site from 100 to 150 K, it splits between two sites from 175 to 295 K with the second site having a lower effective coordination number. This finding along with other structural parameters suggests that Cs rattles in its coordination polyhedron. Pair distribution function measurements reveal that on the length scale of the unit cell, the Pb-I octahedra concurrently become greatly distorted, with one of the I-Pb-I angles approaching 82° compared to the ideal 90°. The rattling of Cs, low number of Cs-I contacts, and high degree of octahedral distortion cause the instability of perovskite-phase CsPbI3. These results reveal the limitations of tolerance factors in predicting perovskite stability and provide detailed structural information that suggests methods to engineer stable CsPbI3-based solar cells.
5. Virtual Symposium

   "National Virtual Biotechnology Laboratory Symposium"

   Wednesday, October 28, 2020, 11:30 am
   Virtual - Registration required

   Hosted by: John Hill

   The symposium is a virtual event to highlight the impact the U.S. Department of Energy's (DOE) National Virtual Biotechnology Laboratory (NVBL) has had utilizing the unique capabilities of the DOE to tackle the science and technology challenges associated with COVID-19, and to discuss areas in which the NVBL can have impact in the future. With perspectives from Chris Fall, Director, Office of Science, DOE, and William A. Bookless, Principal Deputy Administrator of the National Nuclear Security Administration, the event will feature presentations from lead investigators reporting progress in: • Epidemiological modeling • Therapeutics • Testing • Understanding transport of the virus • Solving issues around supply chain challenges In addition, keynote speakers from outside the NVBL will discuss the upcoming science and technology needs in computing, testing and surveillance, and vaccines.
6. NSLS-II Friday Lunchtime Seminar

   "Local structural symmetry breaking at ambient conditions in FeSe superconductor"

   Presented by Robert Koch, Condensed Matter Physics and Materials Science Dept

   Friday, October 23, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   We report pair distribution function measurements of the iron-based superconductor FeSe above and below the structural transition temperature. Structural analysis reveals a local orthorhombic distortion with a correlation length of about 4 nm at temperatures where an average tetragonal symmetry is observed. The analysis further demonstrates that the local distortion is larger than the global distortion at temperatures where the average observed symmetry is orthorhombic. Our results suggest that the low-temperature macroscopic nematic state in FeSe forms from an imperfect ordering of orbital-degeneracy-lifted nematic fluctuations which persist up to at least 300 K.
7. NSLS-II Friday Lunchtime Seminar

   "Structure-based drug development for COVID-19"

   Presented by Desigan Kumaran & Babak Andi, Biology & NSLS-II

   Friday, October 16, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   The recent outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in December 2019 posed great threats to public health and attracted enormous attention around the world. The morbidity and mortality rates associated with COVID-19 in the United States and Europe are increasing exponentially. To date, there are no clinically approved vaccines or antiviral drugs available for these COVID-19 infections and hence there is urgent demand for effective therapeutics and vaccines to control and eradicate the pandemic. We are using structure-based drug discovery (SBDD) approach to develop anti-COVID-19 drugs by targeting multiple viral targets. In order to ramp up the discovery process, we are screening FDA approved drugs with special attention to other existing antiviral and pathogen-specific drugs. Indeed, we have identified few FDA approved drugs that can inhibit (with moderate potency) one of the SARS-CoV-2 viral protein, main protease (Mpro), which play a key role in the viral replication cycle. In this presentation, we will highlight our efforts on SBDD approach on Mpro as a representative target that includes viral protein production, molecular docking studies, in-vitro binding assay and the co-crystal structure determination.
8. NSLS-II Friday Lunchtime Seminar

   "Provenance and workflow tools for multimodal experiments"

   Presented by Line Pouchard, Computational Science Initiative, BNL

   Friday, September 25, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   New data management techniques are needed to address the increasing volume and complexity of data produced by the latest generation of detectors at Scientific User Facilities such as NSLS-II. The experiments carried out by very diverse user communities produce data processed in many unique and highly customized scientific workflows. The facilities exhibit further complexity in large and adaptable collections of instruments, broad ranges of data rates, and data access patterns. In addition, multi-modal techniques that characterize samples with different imaging modalities are poised to further increase the heterogeneity of data processing and analysis methods. One particular challenge is the development of collections of well-annotated datasets for use with machine learning techniques, including provenance. Provenance is the detailed recording of data lineage and software processes operating on data that enable interpreting, validating and reproducing results. This seminar will describe provenance and workflow tools developed by a joint NSLS-II-CSI team under LDRD, including a text mining portal classifying scientific literature papers by XAS edges, and a graph-based provenance wrapper developed for XPD and recently matured to run with a 3D reconstruction code.
9. NSLS-II Friday Lunchtime Seminar

   "Reversible Room-Temperature Fluoride-Ion Insertion in a Tunnel-Structured Transition Metal Oxide Host"

   Presented by Wasif Zaheer, Texas A&M University, TX

   Friday, September 18, 2020, 12 pm
   ZoomGov

   Hosted by: Ignace Jarrige

   An energy storage paradigm orthogonal to Li-ion battery chemistries can be conceptualized by employing anions as the primary charge carriers. F-ion conversion chemistries show promise but have limited cyclability as a result of the significant change in volume of active electrodes upon metal−metal fluoride interconversion. In contrast, the exploration of insertion chemistries has been stymied by the lack of hosts amenable to reversible F-ion insertion at room temperature. In this study, we showed reversible and homogeneous topochemical insertion/deinsertion and bulk diffusion of F ions within the one-dimensional tunnels of sub-micrometer-sized FeSb2O4 particles at room temperature. The insertion of F ions is evidenced by formal oxidation of the iron centers from Fe2+ to Fe3+ with a lattice volume contraction of
10. NSLS-II Friday Lunchtime Seminar

    "Spin-charge Higgs mode in bilayer iridates"

    Presented by Mark Dean, CMPMSD / BNL

    Friday, August 28, 2020, 12 pm
    via Zoom - contact: nsls2user@bnl.gov

    Hosted by: Ignace Jarrige

    Spontaneous symmetry breaking at phase transitions is one of the richest topics in physics describing situations as diverse as magnetism, through freezing, to how elementary particles acquire mass. Phase transitions can be classified into two categories based on whether the phase or the amplitude of the order parameter softens at the transition. In particle physics, both types of transition are well-known and termed either Nambu–Goldstone modes or Higgs Bosons for phase and amplitude modes, respectively. In insulating magnets, order is overwhelmingly conceptualized in terms of phase (i.e. Nambu–Goldstone) softening. In this talk, I will describe our resonant inelastic x-ray scattering (RIXS) experiments which reveal a Higg's amplitudon mode in bilayer magnetic Sr3Ir2O7. We attribute this mode to spin-charge coupled excitations arising from the narrow Mott-gap in this insulator. The material's proximity to a quantum critical point softens the amplitudon to excitation energies only sightly above the phase mode, allowing an active engagement of the mode in the magnetic phase transition. Our work provides a new solid-state platform for research on the dynamics of the Higgs mode and a means to understand novel magneto-transport in moderately correlated magnets.
11. NSLS-II Friday Lunchtime Seminar

    "Phyllosilicates and X-ray amorphous materials on Earth and Mars, characterization with synchrotron radiation"

    Presented by Michael T. Thorpe, NASA Johnson Space Center, Houston, TX

    Friday, August 21, 2020, 12 pm
    ZoomGov

    Hosted by: Ignace Jarrige

    Phyllosilicates and secondary X-ray amorphous materials have the unique ability to record a history of sedimentary processing and the environmental conditions during their formation. These materials are abundant in Martian sedimentary rocks, as identified from the CheMin instrument on the Curiosity rover. However, their atomic structures lack long-range order, making them difficult to characterize with CheMin and laboratory instruments. Synchrotron radiation provides a state-of-the-art technique to characterize the structure and composition of these juvenile alteration products. Using sediments from the basaltic terrains of Iceland , we seek to understand how the composition and short-range atomic order of secondary phases evolve from source to sink.
12. Summer Sundays

    "National Synchrotron Light Source II"

    Sunday, August 16, 2020, 3:30 pm
    Virtual

    Tune in to get an up-close look at the "beamlines" where scientists use ultrabright x-ray light to see the atomic structure of batteries, proteins, and more. Then, viewers will have the opportunity to pose questions to a panel of scientists.
13. NSLS-II Friday Lunchtime Seminar

    "Use of synchrotron X-ray footprinting to reveal allosteric changes in a key plant metabolic enzyme"

    Presented by Rohit Jain, Case Western Reserve University, OH

    Friday, August 7, 2020, 12 pm
    ZoomGov

    Hosted by: Ignace Jarrige

    X-ray footprinting (XFP) is a tried-and-true method for probing macromolecule structure in solution. In XFP, hydroxyl radicals produced by X-ray radiolysis covalently label protein side chains and cleave phosphodiester backbones of nucleic acids, providing insight into macromolecular structure and dynamics that complements data obtained from crystallography, cryo-EM, and small-angle X-ray scattering. XFP beamline (17-BM) at NSLS-II uniquely provides unmatched photon flux density and high level of automation to help resolve challenging biophysical questions, not obtainable by other structural probes. Recent developments in mass spectrometry have advanced the structural analysis and can provide detailed sub-peptide and residue level information for protein footprinting studies. In this talk, we will illustrate the use of synchrotron X-ray footprinting technique for studying structural changes in KIN10 enzyme, a key plant metabolic enzyme, after binding to its phosphorylated disaccharide ligand.
14. NSLS-II Friday Lunchtime Seminar

    "Quantum materials meet coherent x-rays"

    Presented by Xiaoqian Chen, NSLS-II

    Friday, July 31, 2020, 12 pm
    Zoom Invitation

    Hosted by: Ignace Jarrige

    Quantum materials are a class of materials whose properties are deeply rooted in quantum mechanical processes. A few examples include unconventional superconductors and magnets, topological insulators, and multiferroics. Phase nonuniformity and dynamics in quantum materials play a crucial role in deciding their ground states. This calls for a microscopic tool that is also sensitive to a wide range of dynamical time scales. In this talk, I will discuss why synchrotron coherent x-rays are an ideal tool. I will review recent developments in this field with an emphasis on the speckle correlation analysis performed at NSLSII, and discuss some future topics to explore.
15. NSLS-II Friday Lunchtime Seminar

    "New opportunities for IXS at the GALAXIES beamline, Synchrotron SOLEIL"

    Presented by J-P. Rueff, Synchrotron SOLEIL, France

    Friday, July 24, 2020, 12 pm
    Zoom Invitation

    Hosted by: Ignace Jarrige

    The GALAXIES undulator beamline at Synchrotron SOLEIL is dedicated to inelastic x-ray scattering (IXS) and high energy photoemission (HAXPES) spectroscopy in the tender x-ray range (2.3 – 12 keV) [1]. We will present recent scientific results illustrating the capabilities of the IXS endstation at GALAXIES with an emphasis on extreme conditions [2,3] and x-ray Raman spectroscopy [4]. Ongoing instrumental developments for improved energy resolution, faster acquisition scheme and larger collection angle will be discussed. Finally, we will explore the new possibilities offered by the future SOLEIL Upgrade program. [1] Rueff et al., J. Synchrotron Rad. 22 (2015), 175 [2] Lebert et al., PNAS 116 (2019), 20280 [3] Mazzone et al., Phys. Rev. Lett. 124 (2020), 125701 [4] Georgiou et al., Science Advances 5 (2019), eaaw5019
16. NSLS-II Friday Lunchtime Seminar

    "Characterization of Lithium & Sodium Batteries using Synchrotron X-ray Techniques at NSLS II"

    Presented by Zulipiya Shadike, BNL / Chemistry Department

    Friday, July 10, 2020, 12 pm
    via Zoom - contact: nsls2user@bnl.gov

    Hosted by: Ignace Jarrige

    The utilization of anion redox reaction is opening a new approach to increase rechargeable capacities in alkaline ion batteries recently. It is important to understand the oxidation state and electronic structure of anion in the electrodes at different state of charge. Herein, we designed and synthesized the O3-NaCr2/3Ti1/3S2 (NCTS) material, which is delivering a high capacity of 190 mAh g-1 (0.95 Na+) as a cathode for sodium battery based on the cation and anion redox processes. To study the underlying nature of anionic redox chemistry in this layered chalcogenide, we investigated the charge compensation mechanism and structure evolution of NCTS electrode using multi-model synchrotron x-ray techniques and scanning transmission electron microscopy. Our experimental results provided core evidence to reveal various charge compensation mechanisms, involving the formation of electron holes, anionic dimers, and disulfide-like species. These results provide a new insight to clarify the nature of anionic redox process of layered chalcogenides, which is important for the development of novel cathode materials with high energy density.
17. NSLS-II Seminar

    "Considerations of accelerator design for future NSLS-II upgrade"

    Presented by Timur Shaftan, NSLS-II, Accelerator Division Director

    Friday, June 19, 2020, 12 pm
    Zoom Invitation

    Hosted by: Ignace Jarrige
18. NSLS-II Friday Lunchtime Seminar

    "Structural biology in drug discovery: Development of viral protease inhibitors"

    Presented by Scott Lovell, University of Kansas, KS

    Friday, June 12, 2020, 12 pm
    via Zoom - contact: nsls2user@bnl.gov

    Hosted by: Ignace Jarrige

    X-ray crystallography is a widely utilized technique to provide essential high resolution structural information for proteins and is particularly important to determine inhibitor binding modes for drug development. Modern advances in protein crystallization automation, synchrotron X-ray beamlines and crystallographic software development have enabled the rapid determination of crystal structures which has greatly facilitated drug discovery and development projects. Diffraction data for dozens of protein-inhibitor samples can be collected in a matter of hours and immediately analyzed for inhibitor binding using automated crystallographic software pipelines. As such, information regarding the binding modes of various inhibitors can be quickly obtained which facilitates subsequent optimization. Application of these modern structural biology techniques has been critical to the advancement of ongoing collaborative projects focused on the development of covalent inhibitors that target the 3CL proteases of Norovirus, MERS-CoV, SARS-CoV and SARS-CoV-2.
19. NSLS-II Friday Lunchtime Seminar

    "Correlating microscopic materials properties with superconducting qubit performance"

    Presented by Anjali Premkumar, Department of Electrical Engineering, Princeton University

    Friday, June 5, 2020, 12 pm
    via Zoom - contact: nsls2user@bnl.gov

    Hosted by: Ignace Jarrige

    In recent years, evidence has emerged that superconducting qubit performance is limited by imperfections in constituent materials. To characterize the microscopic character of these imperfections, we performed measurements of qubit lifetimes in parallel with structural and electron microscopy of the niobium films used in qubit fabrication. Correlations were found between qubit relaxation times and several materials properties, including grain size, oxide composition on the surface and within grain boundaries, and residual resistance. These findings represent a novel approach to understanding sources of qubit decoherence, utilizing techniques such as hard x-ray photoelectron spectroscopy and transmission electron microscopy.
20. NSLS-II Friday Lunchtime Seminar

    "Understanding the improved cycling performance of sulfurized polyacrylonitrile cathode in Li-S battery"

    Presented by Seongmin Bak, Chemistry Division, Brookhaven National Laboratory

    Friday, May 29, 2020, 12 pm
    via Zoom - contact: nsls2user@bnl.gov

    Hosted by: Ignace Jarrige

    The demands on low cost and high energy density rechargeable batteries for both transportation and large-scale stationary energy storage are stimulating more research toward new battery systems such as metal, metal-sulfur, metal-air, and multivalent batteries. Since sulfur is an earth-abundant material with low cost and has a high theoretical capacity, Li-S battery chemistry has attracted significant interest during the past decade. The Li-S battery utilizes electrochemical conversion of sulfur (S8) to lithium sulfide (Li2S), going through multiple electron transfer processes associated with long- and short-chain polysulfide (Li2Sx) intermediates. It is well known that the long-chain polysulfides can be dissolved into electrolyte with aprotic organic solvents and migrated to the Li anode side. This so-called "shuttle effect" is considered as the main reason for the capacity loss and low coulombic efficiency of the Li-S system. A lot of efforts have been made on how to overcome the problem of polysulfide dissolution through new sulfur-based material and electrolyte, as well as cell engineering. Sulfurized polyacrylonitrile (SPAN) is a promising material capable of suppressing polysulfide dissolution in Li-S batteries with carbonate-based electrolytes. However, undesirable spontaneous formation of soluble polysulfides may arise in the ether-based electrolyte, and the conversion of sulfur in SPAN during the lithiation/delithiation process is yet to be understood clearly. In this talk, our recent characterization study on the SPAN cathode material in Li-S battery using spatially-resolved X-ray fluorescence (XRF) microscopy combined with X-ray absorption spectroscopy (XAS) will be present. The morphology changes and the redistribution of sulfur and polysulfide in both the SPAN cathode and lithium metal anode were monitored through the XRF images, while the chemical state changes of SPAN and sulfur-containing interfacial layer (i.
21. NSLS-II Friday Lunchtime Seminar

    "Catalysis with XAFS and XPS at the Brazilian synchrotron: examples and perspectives"

    Presented by Daniela Coelho de Oliveira, LNLS, Brazil

    Friday, March 6, 2020, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    In this talk, I will present some recent results of catalysts characterization obtained at the Brazilian synchrotron using XAS and/or XPS . I will show a brief perspective of the new capabilities that are planned to attend the catalysis community as well as other research areas.
22. NSLS-II Friday Lunchtime Seminar

    "Probing the short-range spin correlations of CuGeO3 with time-resolved RIXS"

    Presented by Thorsten Schmitt, Paul Scherrer Institut, Photon Science Division, Swiss Light Source, Switzerland

    Friday, February 28, 2020, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Resonant Inelastic X-ray Scattering (RIXS) has become a versatile tool for probing quantum materials, allowing simultaneous access to charge, lattice, spin and orbital degrees of freedom. Much of its success in recent years has been driven by huge improvements in instrumentation, and with the recent advent of X-ray free electron lasers such as the LCLS, it has become possible to translate this technique into the time-domain. Given its ability to address multiple degrees of freedom at once, time-resolved RIXS (trRIXS) therefore has huge potential for investigating materials with cooperative dynamics. Nevertheless, it remains technically very challenging to perform such experiments. We performed trRIXS at the oxygen K-edge in order to probe short-range spin correlations in CuGeO3. This quasi-1D material formed of chains of edge-sharing CuO4 plaquettes, displays pronounced anti-ferromagnetic (AFM) nearest-neighbor spin correlations and transitions into a spin-Peierls phase below 14 K, highlighting a close relation between magnetic and lattice sub-systems. As a result of these AFM correlations a Zhang-Rice singlet (ZRS) exciton can develop during the RIXS process, resulting in a distinct energy loss peak within the charge transfer gap. The amplitude of this ZRS exciton directly reflects the nearest-neighbor AFM correlations [1]. By photoexciting CuGeO3 across the charge gap (~4 eV) we induce a sudden reduction of the intensity of the ZRS exciton within 1 ps, which rapidly recovers before gradually decreasing again towards a stable value after ~10 ps. Comparison to equilibrium measurements and a thermal model reveal that the longer time scale dynamics are dominated by heating of the lattice. However, the initial drop and recovery of the ZRS at short time scales clearly imply a non-thermal behavior. In comparison, lower fluence data shows only a thermal component, suggesting a threshold effect. By comparison with model Hamiltonian calculations we reveal
23. NSLS-II Friday Lunchtime Seminar

    "Effect of Metal (Pt, Ir) Nuclearity in the Subnanometer Regime on CO Oxidation Activity"

    Presented by Ayman M. Karim, Department of Chemical Engineering, Virginia Polytechnic Institute and State University

    Friday, February 21, 2020, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Supported noble metal catalysts are extensively used in industry and their catalytic performance is strongly affected by particle size and shape. In the last decade, supported single atoms and clusters in the subnanometer size regime have attracted a lot of interest since they maximize the metal utilization and have also shown extraordinary catalytic properties for many reactions. However, to tailor the catalyst properties for specific reactions and determine possible limitations, there is a need to understand, on the atomic scale, the origin of reactivity in the subnanometer regime. In this seminar, I will present my group's efforts in understanding the role of metal nuclearity and electronic properties in catalyzing CO oxidation as a model reaction. Using a suite of advanced characterization techniques (aberration-corrected electron microscopy, microcalorimetry, in-situ and in-operando DRIFTS, XPS, EXAFS and HERFD-XANES) complemented by DFT calculations and detailed kinetics measurements, the catalyst structural and electronic properties are identified and correlated with the reaction kinetics. In the talk, CO oxidation on Ir and Pt single atoms and subnanometer clusters supported on MgAl2O4 and CeO2, respectively, will be presented. We identified the active Ir and Pt single atom complexes and show that the reaction follows a combination of Eley-Rideal and Mars-van Krevelen mechanisms. Moreover, we show that despite considered a non-reducible support, CO oxidation on MgAl2O4 supported Ir subnanometer clusters follows a similar mechanism as on a reducible oxide where O2 is activated at the metal-support interface. Finally, the role of metal-support interaction in O2 activation and effect of CO binding strength on the catalytic activity will be discussed.
24. NSLS-II Colloquium

    "Subsurface Landscapes of Oxidation and Reaction in the Critical Zone"

    Presented by Susan Brantley, Pennsylvania State University, PA

    Thursday, February 13, 2020, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: John Hill

    The globally ubiquitous mineral pyrite oxidizes even at low oxygen concentrations. As the most common crustal sulfide, pyrite reactivity impacts sulfur, iron, oxygen, and carbon budgets globally. We discovered that pyrite oxidizes completely at tens of meters depth even in low-porosity rocks in catchments in humid climates. As erosion exposes the pyrite to near-surface conditions in low porosity rocks, pore and fracture development is the main control on the rate of oxidative weathering. Between fractures, oxygen diffusion limits the weathering and oxidation is inferred to be largely abiotic because bacteria cannot enter rock matrix pores. Oxygen concentrations and erosion rates together can explain pyrite-derived sulfate fluxes in rivers to the ocean and may account for the presence or absence of pyrite in detrital sediments over Earth history.
25. NSLS-II Friday Lunchtime Seminar

    "Tracing Processes Involving the Reactive Intermediates of To Better Understand the Role of Sulfur Cycling on the Fate of Arsenic and Iron in Sediments; Using Reactive Intermediates to Document Extensive Cryptic Sulfur Cycling Affecting Arsenic Levels"

    Presented by BENJAMIN C. BOSTICK, Columbia University, Palisades, NY

    Friday, January 31, 2020, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Arsenic (As) groundwater contamination is thought to result from the reductive dissolution of As-bearing iron oxides by microorganisms. Our understanding of the how reactions occur commonly depends on observing the consumption and production of reactants and products respectively. This approach can be insufficient in environmental systems containing complex compositions and phases that can react through multiple and distinct coupled biological and chemical processes. We suggest it is more effective to study environmental processes by considering dissolved and mineral species as reactive intermediates in geochemical cycles where their concentration is controlled by the balance between their production, consumption and transport. Here, we apply this approach to elucidate a critical role of sulfur (S) cycling in iron reduction in sediments affected by As contamination. Arsenic (As) contamination in soil and groundwater is commonly associated with iron reduction because the concentration of dissolved As and Fe(II) increase together as Fe(III) minerals convert to Fe(II) minerals. In contrast, sulfate concentrations are usually low and stable in groundwaters affected by As. This stability is often interpreted as evidence for the minimal role of S cycling in Fe reduction; however, there is mounting biochemical and mineralogical evidence that sulfate reduction is active and critical to both Fe(III) reduction and As mobilization. Sediment iron mineralogies indicate that reactive Fe(III) minerals are present in most sediments and this Fe(III) is particularly susceptible to chemical and biological reduction. These Fe minerals were transformed to Fe(II) carbonate, green rusts, and, rarely, iron sulfides as the sediments became reduced. The microorganisms identified in sediments undergoing reduction were not iron reducers, and often were autotrophs involved in S cycling. This data suggests that sulfate reduction is active, and tightly coupled to the oxidation of sulfide and elem
26. NSLS-II Friday Lunchtime Seminar

    "Real-space Local Correlated Motion in Liquids studied by using Inelastic Scattering"

    Presented by Yuya Shinohara, Oak Ridge National Laboratory

    Friday, January 17, 2020, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Liquids are critical to our daily life. A paramount example is water, which covers 70% of the Earth's surface and make up about 80% of our body. Liquids are also crucial to many current energy technologies. Despite their importance, our understanding of liquids at the atomic level is much poorer than that for crystalline solids. Particularly elusive is a detailed description of the correlated dynamics in liquids, which is the key to controlling the transport properties of liquids. Recent progress in inelastic X-ray/neutron scattering makes it possible to obtain inelastic scattering spectra over a wide energy transfer (E) and momentum transfer (Q) with a high E- and Q-resolution within a reasonable amount of time. This enables us to calculate the Van Hove correlation functions via Fourier transform. With this novel approach, we have determined spatial and temporal correlations of molecular motion of liquids. In this presentation, I will present our recent efforts in understanding the real-space local correlated motion in liquids.
27. CSI Q Seminar

    "Probing quantum entanglement at the Electron Ion Collider"

    Presented by Dmitri Kharzeev, Stony Brook University and BNL

    Wednesday, December 18, 2019, 1:30 pm
    Training Room, Bldg 725

    Hosted by: Layla Hormozi

    The structure functions measured in deep-inelastic scattering are related to the entropy of entanglement between the region probed by the virtual photon and the rest of the hadron. This opens new possibilities for experimental and theoretical studies using the Electron Ion Collider. The real-time evolution of the final state in deep-inelastic scattering can be addressed with quantum simulations using the duality between high energy QCD and the Heisenberg spin chain.
28. NSLS-II Friday Lunchtime Seminar

    "Operation at 500mA average current on the horizon"

    Presented by Alexei Blednykh, NSLS-II

    Friday, December 6, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Igna

    500mA average current achieved in NSLS-II. Limitations on the total average current will be discussed in details. Localized heating of the vacuum components was the major issue. Since the heating issues were resolved we were able to demonstrate 500mA during the beam study time. However, for the regular operation @500mA we need more power from the RF system to compensate the synchrotron radiation losses produced by the bending magnets, present and future insertion devices. To mitigate the heating issue and increase the beam stability, bunch lengthening will be beneficial for NSLS-II.

Currently showing events from the past year. See all past events »

1. Short Course on X-ray Absorption Fine Structure: Application to Nanomaterials (XAFS 2020)

   November 18-20, 2020
2. MX Macromolecular Training Workbench (2020-3)

   November 3-5, 2020
3. LiX Solution Scattering Workbench (2020-3)

   November 3-5, 2020
4. MX Macromolecular Training Workbench (2020-2)

   July 29-31, 2020
5. LiX Solution Scattering Workbench (2020-2)

   July 27-29, 2020
6. NSLS-II and CFN Users' Meeting

   May 18-20, 2020
7. LiX Solution Scattering Workbench 2020

   February 13-15, 2020
8. Short Course on X-ray Absorption Fine Structure: Theory, Data Analysis and Modeling (XAFS 2019)

   November 13-15, 2019
9. Exploring New Science Frontiers at NSLS-II

   October 21-23, 2019
10. LiX Solution Scattering Workbench (2019-3)

    September 23-25, 2019
11. Teacher Training: Exploring Proteins with a New Light

    July 1-3, 2019
12. 11th International Conference on Inelastic X-ray Scattering (IXS2019)

    June 23-28, 2019
13. 4th International Conference on Resonant Elastic X-ray Scattering (REXS 2019)

    June 17-21, 2019
14. LiX Solution Scattering Workbench

    May 29-31, 2019
15. 2019 NSLS-II & CFN Joint Users' Meeting

    May 20-22, 2019
16. In Celebration of International Women's Day 2019

    March 8, 2019
17. LiX Solution Scattering Workbench

    February 14-16, 2019
18. Short Course: Introduction to X-ray Absorption Spectroscopy

    November 6-8, 2018
19. NOBUGS 2018: New Opportunities for Better User Group Software

    October 22-26, 2018
20. NSLS-II Pair Distribution Function School 2018

    September 17-19, 2018
21. 10th International Workshop on X-ray Radiation Damage to Biological Samples

    September 13-14, 2018
22. Coherence 2018: International Workshop on Phase Retrieval and Coherent Scattering

    June 24-28, 2018
23. 2018 NSLS-II and CFN Users' Meeting

    May 21-23, 2018
24. Data Analysis and Modeling of XANES and EXAFS Spectra: Applications to Nanomaterials

    November 1-3, 2017
25. Synchrotron Environmental Science Symposium 7: Illuminating the Links Between Environmental Science and Human Health

    October 30 - November 1, 2017
26. 2017 NSLS-ll and CFN Users' Meeting

    May 15-17, 2017
27. High-Brightness Synchrotron Light Source Workshop

    April 26-27, 2017
28. X-ray Absorption Fine Structure Spectroscopy (XAFS) Short Course: Principles and Applications

    November 2-4, 2016
29. 14th International Conference on Surface X-ray and Neutron Scattering (SXNS14)

    July 10-14, 2016
30. 2016 NSLS-ll and CFN Users' Meeting

    May 23-25, 2016
31. Short Course: Advanced Topics in XAFS Data Analysis and Modeling

    November 5-7, 2015
32. 8th International Workshop on Infrared Microscopy and Spectroscopy using Accelerator Based Sources

    October 11-15, 2015
33. Collaboration Meeting on "Simulation and Modeling for SR Sources and X-Ray Optics"

    October 1-2, 2015
34. NSLS-II Strategic Planning Workshop

    September 24-25, 2015
35. 23rd International Congress on X-ray Optics and Microanalysis (ICXOM23)

    September 14-18, 2015
36. Complementary Methods in X-ray Spectroscopic, Structural, and Imaging Techniques

    July 13-14, 2015
37. 12th International Conference on Synchrotron Radiation Instrumentation (SRI 2015)

    July 6-10, 2015
38. BES Facilities Computing Working Group Meeting - May 21-22, 2015

    May 21-22, 2015
39. 2015 NSLS-II & CFN Joint Users' Meeting

    May 18-20, 2015
40. First Science at the ABBIX Beamlines

    April 21-22, 2015
41. Short Course: Methods and Applications of X-Ray Absorption Fine Structure Spectroscopy

    November 13-15, 2014
42. NSLS "Last Light"

    September 30, 2014
43. Remote Access Data Collection: Automation and Robotics at the SSRL Protein Crystallography Beam Lines

    July 17-18, 2014
44. Joint NSLS/NSLS-II & CFN Users' Meeting

    May 19-21, 2014
45. X9 SAXS Workbench

    April 24-27, 2014
46. Industrial Research at NSLS-II

    April 8-9, 2014
47. X6A Workbench: Hands-on Synchrotron Structural Biology

    February 25-28, 2014
48. X6A Workbench: Hands-on Synchrotron Structural Biology

    October 29 - November 1, 2013
49. In-situ Methods of X-ray Absorption Spectroscopy

    October 24-26, 2013
50. NSLS-II Early Experiment Workshop: IXS Focused Session

    October 1, 2013
51. NSLS-II First-Experiments Workshop

    August 12-13, 2013
52. X6A Workbench: Hands-on Synchrotron Structural Biology

    June 25-28, 2013
53. NSLS and CFN Users' Meeting

    May 20-22, 2013
54. Seventh International Workshop on Radiation Safety at Synchrotron Radiation Sources

    May 8-10, 2013
55. RapiData 2013

    April 21-26, 2013
56. X9 SAXS Workbench

    April 18-21, 2013
57. MXLS13 "New Opportunities for Magnetic Dynamics and Materials at NSLS-II and MAX-IV”

    March 24-28, 2013
58. X6A Celebrates Its 10th Anniversary!

    February 1, 2013
59. X6A Workbench: Hands-on Synchrotron Structural Biology

    January 28 - February 1, 2013
60. XANES Short Course: Theory, Analysis, Applications

    November 8-10, 2012
61. X9 SAXS Workbench

    September 20-23, 2012
62. Rock & Cell: From the Meso- to the Nanoscale with X-ray Spectromicroscopy

    September 17-18, 2012
63. X9 SAXS Workbench

    June 21-24, 2012
64. Crystallography Workbench

    June 11-13, 2012
65. Synchrotron Radiation in Art and Archaeology

    June 5-8, 2012
66. Synchrotron Radiation in Art and Archaeology (SR2A)

    June 5-8, 2012
67. 2012 NSLS/CFN Joint Users' Meeting

    May 21-23, 2012
68. Operando IV

    4th International Congress on Operando Spectroscopy

    April 29 - May 3, 2012
69. 4th International Congress on Operando Spectroscopy

    April 29 - May 3, 2012
70. Joint InSynC-INCREASE Workshop

    April 18-19, 2012
71. X6A Workbench: Hands-on Synchrotron Structural Biology

    March 27-30, 2012
72. X9 SAXS Workbench

    March 8-10, 2012
73. XAFS Short Course: Introduction to the Experiment, Data Analysis and Modeling

    November 3-5, 2011
74. X9 SAXS Workbench

    October 13-16, 2011
75. Photon Sciences Users' Executive Committee and Town Meetings

    August 12, 2011
76. Materials Diffraction Suite Workshop

    July 18-20, 2011
77. 2011 NSLS/CFN Users' Meeting

    May 23-25, 2011
78. Workshop on Supercritical Carbon Dioxide-Materials Interactions

    March 21-23, 2011
79. Advanced Topics in XAFS Data Modeling

    November 4-6, 2010
80. EPICS Collaboration Meeting - Fall 2010

    October 7-14, 2010
81. 2010 Joint NSLS and CFN Users Meeting

    May 24-26, 2010
82. In Situ and Operando XAFS Experiments and Data Analysis

    October 22-24, 2009
83. MX Frontiers at the One Micron Scale

    July 23-24, 2009
84. The Experimental Program to Stimulate Competitive Research (EPSCoR) Review 2009

    July 20-23, 2009
85. INCREASE Workshop

    Interdisciplinary Consortium for Research and Educational Access in Science and Engineering

    July 15-17, 2009
86. International Workshop for New Opportunities in Hard X-ray Photoelectron Spectroscopy: HAXPES 2009

    May 20-22, 2009
87. 2009 NSLS / CFN Users' Meeting

    May 18-20, 2009
88. Applications of Synchrotron Techniques in Glass Research

    April 6-7, 2009