1. NSLS-II Seminar

   "2019 NSLS-II Summer Intern Mini-Symposium"

   Presented by John Hill, Welcome & will introduce 11 speaker, Interns with NSLS-II

   Thursday, August 1, 2019, 1 pm
   Large Seminar Room, Bldg. 510

   Hosted by: Lisa Miller

   Will forward flyer upon request (morello@bnl.gov)
2. NSLS-II Friday Lunchtime Seminar

   "Quantum materials based on metamorphic InAsSb superlattices"

   Presented by Sergey Suchalkin, Stony Brook University, Stony Brook, NY

   Friday, June 28, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   Recently proposed metamorphic InSbxAs1-x/InSbyAs1-y superlattices (SLs) manifest a new class of bulk materials where the bandgap can be tuned down to negative values [1,2]. Application of the virtual substrate approach relieves the limitation dictated by the substrate lattice constant and makes possible to grow materials with high crystalline quality in the entire range of alloy compositions. While remaining viable candidates to compete with the state-of-the-art mercury-cadmium-telluride (MCT) compound materials in the field of infrared detection and imaging, the new low-bandgap InAsSb SLs are new platform for investigation of intriguing physical phenomena such as the quantum spin Hall effect, and Majorana zero modes which has recently appeared in the searchlight of solid-state physics. I will present the latest results on experimental and theoretical analysis of carrier dispersion and band structure of short period metamorphic InSbxAs1-x/InSbyAs1-y superlattices, obtained in the Optoelectronics group of Stony Brook University. We demonstrate that the Dirac dispersion is realized in short period InAs1-x Sbx/InAs1-ySby metamorphic superlattices with the bandgap tuned to zero by adjusting the superlattice period and layer strain [3,4]. It was shown that the new material has anisotropic carrier dispersion: the carrier energy associated with the in-plane motion is proportional to the wave vector and characterized by the Fermi velocity vF, the dispersion corresponding to the motion in the growth direction is quadratic. Remarkably, the Fermi velocity in this system can be controlled by varying the overlap between electron and hole states in the superlattice [3]. We present a picture of modification of the energy spectrum due to variation of layer thicknesses, strain and composition of the SLs. The effects of dimensional quantization, tunneling and interface scattering on the SL band structure will be discussed. 1 - G. Belenky, D. Wang, Y. Lin, D. Donetsk
3. NSLS-II Friday Lunchtime Seminar

   "Recent progress on the electronic structure study of the heavy-fermion Ce-115 compounds"

   Presented by Qiuyun Chen, Science and Technology on Surface Physics and Chemistry Laboratory, China

   Friday, June 21, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   Here we performed a combined bulk-sensitive soft x-ray angle-resolved photoemission spectroscopy (ARPES) and Ce 4d-4f resonant ARPES studies of the three parent compounds of the Ce-115 system: CeCoIn5, CeRhIn5, and CeIrIn5. In CeCoIn5, we spectroscopically resolved the development of band hybridization and the Fermi surface expansion over a wide temperature region. Unexpectedly, the localized-to-itinerant transition occurs at surprisingly high temperatures, yet f electrons are still largely localized even at the lowest temperature. These findings point to an unanticipated role played by crystal field excitations in the strange metal behavior of CeCoIn5. In CeRhIn5, we have directly observed a weakly dispersive heavy quasiparticle band in this heavy fermion compound, whose f-electrons are considered most fully localized. Two of the three crystal-electric-field (CEF) split levels of the Ce 4f5/21 states have been observed at 2.5 and 10 meV above the Fermi energy, with distinctive symmetries. The hybridization mainly happens between these states and Rh 4d band near the Brillouin zone center, on the most three-dimensional Fermi pocket. Remarkably, the f electrons start to turn itinerant at the highest sampling temperature, 180 K, a high temperature scale that is known to be consistent with the CEF splitting. In this important heavy fermion compound with antiferromagnetic state, we paint a comprehensive picture of the dual nature of the f electrons. In CeIrIn5, we find similar behaviors of the f electrons with that of CeCoIn5, and the hybridization also starts at much higher temperature than Tk. We also provide the first experimental evidence for 4f7/21 splittings which, in CeIrIn5, split the octet into four doublets. Our results offer a comprehensive and in part, unanticipated experimental picture of the heavy fermion formation, setting the stage for understanding the emergent properties, including unconventional superconductivity, in this and related material
4. NSLS-II Friday Lunchtime Seminar

   "High resolution strain measurements and phase discrimination in solid solutions using X-Ray Diffuse Multiple Scattering (DMS)"

   Presented by Gareth Nisbet, Diamond Light Source, United Kingdom

   Friday, June 14, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   DMS is a new high resolution scattering technique which manifests as diffraction lines impinging on the detector plane, similar to Kikuchi lines or Kossel lines. I will explain how multiple intersections from coplanar and non-coplanar reflections can be used for phase discrimination in multi-phasic systems by following a simple reductive procedure. The methods will be demonstrated using data from complex PMN-PT and PIN-PMN-PT ferroelectric solid solutions. I will also show how convolutional neural networks are being applied to DMS data for phase discrimination.
5. NSLS-II Friday Lunchtime Seminar

   "Status and perspective of high-energy automotive batteries"

   Presented by Richard Schmuch, University of Munster, Germany

   Friday, June 7, 2019, 12:30 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   This presentation gives an overview of the materials, performance requirements and cost of current automotive traction batteries based on Li-ion technology. It also includes important aspects related to electromobility, such as its sustainability and energy efficiency. As current Li-Ion batteries with intercalation-type active materials are approaching their physicochemical energy density limit of roughly 300 Wh/kg or 800 Wh/L, alternative technologies such as lithium-metal based all-solid-state batteries (ASSBs) currently intensively studied, which promise an energy density of up to 1000 Wh/L. The potential and challenges of this and other post Li-ion batteries (e.g. Dual-Ion, Mg-Ion, Li-Sulphur) are discussed and also compared by systematic bottom-up energy density calculations. Through a step-by-step analysis from theoretical energy content at the material level to practical energies at the cell level, the individual advantages and shortcomings of the studied battery types are elucidated. Literature: (1) Schmuch, R.; Wagner, R.; Hörpel, G.; Placke, T.; Winter, M. Performance and Cost of Materials for Lithium-Based Rechargeable Automotive Batteries. Nat. Energy 2018, 3 (4), 267–278. (2) Betz, J.; Bieker, G.; Meister, P.; Placke, T.; Winter, M.; Schmuch, R. Theoretical versus Practical Energy: A Plea for More Transparency in the Energy Calculation of Different Rechargeable Battery Systems. Adv. Energy Mater. 2018, 1803170, 1803170. (3) Placke, T.; Kloepsch, R.; Dühnen, S.; Winter, M. Lithium Ion, Lithium Metal, and Alternative Rechargeable Battery Technologies: The Odyssey for High Energy Density. J. Solid State Electrochem. 2017, 1–26. (4) Meister, P.; Jia, H.; Li, J.; Kloepsch, R.; Winter, M.; Placke, T. Best Practice: Performance and Cost Evaluation of Lithium Ion Battery Active Materials with Special Emphasis on Energy Efficiency. Chem. Mater. 2016, 28 (20), 7203-7217
6. NSLS-II Friday Lunchtime Seminar

   "Longitudinal Coupling Impedance and Single-Bunch Instability"

   Presented by Alexei Blednykh, NSLS-II

   Friday, June 7, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   Several instability thresholds and special waveform beam pattern have been observed during measurements of the electron beam energy spread σ_δ versus single-bunch current I_0 in NSLS-II. The experimental data have been collected from: the synchrotron light monitor (SLM) camera installed in a low dispersion area of the NSLS-II storage ring, the Full-Width Half-Maximum size of the In-Vacuum Undulator harmonic, the stripline kicker as a part of the bunch-by-bunch transverse feedback system and the large gap dipole chamber of Optical Extraction Beamline in NSLS-II. With mentioned measurement techniques we were able to confirm, that the microwave beam pattern behavior as a current dependent effect. The numerical simulations of the Vlasov-Fokker-Planck (VFP) equation with the longitudinal impedance budget simulated by the GdfidL code for a 0.3mm bunch length and the total longitudinal wakepotential W_(||,tot)(s), allowed us to reproduce the energy spread dependence on the single bunch current numerically for different lattices, bare lattice and regular operational lattice with all insertion devices magnet gap closed, including 3 damping wigglers. The present talk will be based on the results published in the Scientific Reports, 2018: A. Blednykh, B. Bacha, G. Bassi, W. Cheng, O. Chubar, A. Derbenev, R. Lindberg, M. Rakitin, V. Smaluk, M. Zhernenkov, Yu-chen Karen Chen-Wiegart and L. Wiegart, "New aspects of longitudinal instabilities in electron storage rings", Scientific Reports volume 8, Article number: 11918 (2018).
7. NSLS-II Friday Lunchtime Seminar

   "Microspectroscopy of Extraterrestrial Materials, or, The Universe Viewed Through a Microscope"

   Presented by Paul Northrup, Stony Brook University

   Friday, May 31, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   Synchrotron X-ray absorption fluorescence spectromicroscopy is an essential tool for characterization of heterogeneous (and often very small) extraterrestrial materials. A NASA-funded research program utilizes the TES (8-BM) and XFM (4-BM) to study composition and chemistry of extraterrestrial materials, especially focusing on return-mission samples. Of particular interest are Phosphorus and Sulfur compounds that may be either a) organic evidence of life, or b) precursors or critical raw materials for development of life, on early Earth or elsewhere. Initial samples include meteorites, interplanetary dust particles, and Lunar materials. Current sample-return missions (NASA OSIRIS REx and Japan's Hayabusa2) will retrieve material from distant asteroids in a few years. Future missions will return samples from Mars.
8. NSLS-II Friday Lunchtime Seminar

   "THz vortex beam as a spectroscopic probe of magnetic excitations"

   Presented by Andrei A. Sirenko, New Jersey Institute of Technology, NJ

   Friday, May 24, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   Circularly polarized light with spin angular momentum (SAM) is one of the most valuable probes of magnetism. We demonstrate that light beams with orbital angular momentum (OAM), or vortex beams, can also couple to magnetic excitations exhibiting dichroisms in a magnetized medium. In our recent experiments with coherent THz beams we observed that resonant optical absorption in a ferrimagnetic crystal of Dy3Fe5O12 depends strongly on both the handedness of the vortex and direction of the beam propagation with respect to the sample magnetization. This effect exceeds the conventional dichroism for conventional circularly polarized light. Our results demonstrate the potential of the vortex beams with OAM as a new spectroscopic probe of magnetism in matter. A possibility to convert synchrotron radiation at the 22-IR-2 MET beamline into a vortex beam and use it for materials spectroscopy will be also discussed in this talk. In collaboration with T. N. Stanislavchuk1, P. Marsik2, C. Bernhard2, V. Kiryukhin3, S-W. Cheong3, and G. L. Carr4 1 Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 2 Department of Physics, University of Fribourg, Switzerland. 3 Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University 4 NSLS-II, Brookhaven National Lab
9. NSLS-II Friday Lunchtime Seminar

   "MAXPD: Multi-Anvil X-ray Powder Diffraction — COMPRES Partner User Program for High Pressure Studies at 28-ID-2-D"

   Presented by Matthew L. Whitaker, Stony Brook University

   Friday, May 17, 2019, 12 pm
   NSLS-II Bldg. 743 Room 156

   Hosted by: Ignace Jarrige

   MAXPD is the downstream endstation of XPD, an insertion device beamline at Sector 28 (28-ID-2-D) of NSLS-II. The MAXPD endstation and General User Program are sponsored by the COnsortium for Materials Properties Research in Earth Sciences (COMPRES). MAXPD has an 1100-ton hydraulic press installed, which is equipped with a unique DT-25 pressure module that can be swapped out for a more standard D-DIA module as desired. MAXPD makes use of the world-class monochromatic beam available at XPD (usually ~67 keV), with which we collect both angular dispersive X-ray diffraction data and X-radiographic imaging. The first General User experiments took place in March 2018. Final Science Commissioning beamtime took place in August of last year, and the full General User program for MAXPD began in the 2018-3 cycle. In this seminar, I will give an overview of the science drivers behind the development of the endstation, some of its unique capabilities, some representative results from recent experiments conducted over the last two cycles at MAXPD, and where we are looking to go as we look to the future.
10. NSLS-II Friday Lunchtime Seminar

    "Self-assembly of anisotropic nanocrystals from crystalline to quasicrystalline structures"

    Presented by Ou Chen, Brown University, Rhode Island

    Friday, May 10, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Anisotropic nanocrystals with defined composition, shape and surface patchiness represent a unique class of building objects for constructing high-order architectural nanomaterials. When utilized in assembly, anisotropic nanocrystals can display strong asymmetric interactions induced by the patchiness that may complicate the formation of ordered structures compared to the assemblies of isotropic building blocks. In this talk, I will use several types of anisotropic 'patchy' nanocrystals as examples to demonstrate how they assemble into the unprecedented superstructures through the directional interactions among the building blocks under an enthalpy-driven condition. Both translational periodicities and orientational ordering of the final superstructural materials will be discussed. The dominating driving forces lead to the obtained architectures will be identified through molecular dynamics computer simulations and experimental results.
11. NSLS-II Friday Lunchtime Seminar

    "In situ studies of Zr-based MOFs for nerve-agents capture and decomposition"

    Presented by Anna M. Plonka, Stony Brook University, Dept. of Mat. Sci. & Chem. Eng.

    Friday, May 3, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Effective filters for the rapid decomposition of chemical warfare agents (CWAs) are in high demand for protecting military and civilian populations. Although many new materials, such as metal-organic frameworks (MOFs), have been proposed to use as CWA filtration media, their eventual transition requires a detailed understanding of the atomic-scale reaction mechanisms. Zr-based MOFs were recently shown to be among the fastest catalysts of nerve-agent hydrolysis reaction in solution. We show the results of a detailed study of the adsorption and decomposition of a nerve-agent simulant, dimethyl methylphosphonate (DMMP), on Zr-based MOFs, that have different pore sizes and connectivities, using synchrotron-based X-ray powder diffraction, X-ray absorption and infrared spectroscopy, which reveals key aspects of the reaction mechanism. Further, we evaluate how battle-field contaminants such as CO2 can influence effective detoxification of CWAs by Zr-based MOF-808.
12. NSLS-II Friday Lunchtime Seminar

    "Coherent X-ray measurement of local step-flow propagation during growth of polycrystalline organic semiconductor thin films"

    Presented by Randall Headrick, University of Vermont

    Friday, April 26, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Vacuum deposition of C60 on a graphene-coated surface is investigated with X-ray Photon Correlation Spectroscopy in surface-sensitive conditions. Local step-flow is observed through the observation of oscillatory correlations in the later stages of growth after crystalline mounds have formed. An important aspect of the work is that coherent X-rays do not average over complex structures, and this allows us to monitor the growth on polycrystalline surfaces without loss of information. The experimental results show that the step-flow velocity must be nonuniform, and we model the velocity of each step-edge as being a simple function of the lengths of the terraces above and below it. This model predicts that the steps become almost stationary near the edges of the mounds where the local terrace length is very small, and the average slope of the surface is large. It was not previously known that such nonuniform and disordered step arrays as we have observed would follow such a simple growth law. This work shows that the use of coherent X-ray scattering provides an approach to better understand surface dynamics and fluctuations during crystal growth.
13. NSLS-II Friday Lunchtime Seminar

    "Wireless Sensors, and updates to areaDetector with Computer Vision"

    Presented by Kazimierz Gofron, NSLS-II

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

    Hosted by: Ignace Jarrige

    by K. Gofron, M. Rolland, J. Wlodek, The series of brief talks that concentrate on EPICS controls 1. Wireless sensors controlled from EPICS 2. Improvements to Area Detector at NSLS2 A. Low Energy, Low Cost: The Nordic Thingy:52 Sensor Suite 1. Wireless technologies 2. EPICS controls of wireless sensors 3. ioc components 4. Integrated into CSS, and clients B. Improvements to Area Detector deployment and features at NSLS2 1. ADPluginBar/Dmtx – QR Code and data matrix code readers for EPICS Area Detector 2. ADLambda – Adding new features to an existing driver, and updating to build on newer OS 3. ADCompVision – Bringing Computer Vision to Area Detector 4. ADUVC – An area detector driver for USB Video Class devices 5. ADEmergentVision – An area detector driver for Emergent Vision Technologies 10 GigE and 25 GigE cameras
14. NSLS-II Colloquium

    "NASA's Mars 2020 Mission – First Steps Towards Mars Sample Return"

    Presented by Kenneth Farley, Caltech

    Thursday, April 11, 2019, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: John Hill

    Scientists have advocated for the return of samples from Mars for decades. The quest has finally begun in earnest: the Jet Propulsion Laboratory is in the final stages of construction of the Mars 2020 mission. Mars 2020 builds on the highly successful design of the Mars Science Laboratory (Curiosity Rover) and is updated with new landing capabilities, scientific instruments, and a very sophisticated rock sample collection system. Mars 2020's chief goals are to unravel the geology of its landing site, seek evidence of potential Martian biosignatures, and prepare a cache of several dozen samples for possible return to Earth by a future element of a notional Mars Sample Return campaign. NASA recently selected the mission's destination: Jezero Crater. This crater once held a very deep lake comparable in size to Lake Tahoe. Key geologic targets at the site include ancient Martian bedrock, lake sediments and especially a remarkably preserved river delta, and unusual carbonate-bearing rocks possibly precipitated from lake-water. Mars 2020 will launch in the summer of 2020, land on February 18, 2021, and rove the surface for at least two years. I am Project Scientist for Mars 2020 and will describe the goals and development of this mission, and of Mars sample return.
15. NSLS-II Friday Lunchtime Seminar

    "Towards studying dynamics over 18 decades with correlation spectroscopy – first XPCS results from European XFEL"

    Presented by Felix Lehmkuehler, Coherent X-ray Scattering Group, DESY, Germany

    Friday, April 5, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Many phenomena in soft matter physics and biology happen on microsecond timescales, e.g., folding kinetics of proteins, where the time scale is basically defined by the protein size. Despite of the importance of such processes, μs time scales are very difficult to access in X-ray scattering experiments at storage rings as well as in quasi-elastic neutron scattering. The time structure of the European XFEL with MHz pulse repetition rate in a bunch train enables for the first time structural studies of dynamics and kinetics at such time scales. A method to investigate such phenomena is X-ray photon correlation spectroscopy (XPCS), tracking changes of the coherent diffraction pattern, the so-called speckle pattern, over time. XPCS has become a well-established technique at modern storage ring sources studying timescales ranging from several 1000 s down to milliseconds. At FEL sources, the higher average flux and superior degree of coherence allow the access to shorter timescales down to femtoseconds using split-pulse techniques. On the other hand, sequential-pulse XPCS is limited by the repetition rate of the FEL pulses, i.e. about 8 to 50 ms at normal-conducting hard X-ray FEL sources such as LCLS (USA) and SACLA (Japan). The high repetition rate of the European XFEL enables dynamics measurement on sub-μs time scales, which is otherwise difficult to achieve at storage ring, neutron, pump-probe or lab-based experiments. In this talk, first dynamics measurements at FEL sources using correlation techniques will be introduced and recent results on prototypical soft matter samples as well as fs dynamics of liquid water will be discussed. Afterwards, results from our recent XPCS experiment at European XFEL will be discussed, where we successfully performed measurements of (sub-)µs dynamics of soft matter samples. Furthermore, special attention is paid on shot-to-shot and train-to-train fluctuations of coherence and beam pointing obtained by c
16. NSLS-II Friday Lunchtime Seminar

    "X-ray holography correlation spectroscopy: How to probe stochastic dynamics on the nanoscale"

    Presented by Christopher Klose, Max Born Institute, Berlin, Germany

    Friday, March 29, 2019, 12:30 pm
    NSLS-II Bldg 744 Rm 156

    Hosted by: Ignace Jarrige

    Nanometer-scale spin configurations such as magnetic domains walls (DW) or skyrmions are attractive as information entities for spintronic applications as they can be generated and manipulated by electrical spin-polarized currents. Naturally, the function of such devices is crucially determined by the thermal stability of the magnetic configuration used for encoding the information. In our study, we have investigated thermally activated magnetic DW dynamics on timescales ranging from sub-seconds to hours under equilibrium conditions in a thin-film magnetic multilayer material based on 15 repetitions of Pt/CoFeB/MgO trilayers. Such multilayers were already successfully used to demonstrate the basic operation of a skyrmion-based racetrack memory [1]. For our investigations, we developed a new experimental approach combining real-space imaging via Fourier-transform holography [2] and x-ray photon correlation spectroscopy [3]. Both methods rely on detecting coherent far-field diffraction from a disordered sample —a pattern of magnetic up and down domains in our case. Magnetic contrast is achieved by tuning the wavelength of circularly polarized x-rays to the Co L3 absorption edge (1.6 nm). For slow timescales (> 3 min), the analysis is based on the difference of scattering patterns recorded with opposite x-ray helicity (Fig. 1a). On one hand, the Fourier inversion of this difference results in a real-space image of the domains in the field of view (FOV) defined by a circular optics mask on the sample (Fig. 1b). On the other hand, we use the difference as input for an adapted temporal correlation analysis. Already at slightly elevated temperatures (310 K), the resulting two-time correlation function of the magnetic configuration at times t1 and t2 (Fig. 1c) reveals time periods of high correlation, i.e., high stability interrupted by sudden extensive domain rearrangements as witnessed by the related images.
17. NSLS-II Friday Lunchtime Seminar

    "Can We Make X-ray CT More Universal?"

    Presented by Jun Lim, Pohang Light Source-II, Korea, Republic of (South)

    Friday, March 29, 2019, 12 pm
    NSLS-II Bldg 744 Rm 156

    Hosted by: Ignace Jarrige

    Full-field transmission x-ray microscope (TXM) based on Fresnel zone plate is a promising and intuitive manner to take high quality phase contrast images with spatial resolution of tens of nanometers, applicable to both synchrotron radiation and laboratory source. In particular, computed tomography (CT) using hard x-rays of high penetration depth provides a high-resolution 3D image. However, the small field of view (FOV) of ~10 microns provides only a very limited volume (~10-5 mm3) of information. It primarily limits the application area of TXM. In this talk, I present a new type of TXM for CT that enlarge the FOV as large as diameter of the objective zone plate. With this method, sub-millimeter FOV can be realized while maintaining the nano-scale spatial resolution. Through experiment, we obtain more than 1000 times more volume (~10-2 mm3) of information than a typical TXM, at ~200 nm resolution. Its general applicability is demonstrated with integrated chips and Artemia cysts. We believe that this type of TXM can be particularly useful for industrial sample analysis where bulk properties are important.
18. NSLS-II Friday Lunchtime Seminar

    "Selective Catalytic Olefin Epoxidation with MnII-exchanged MOF-5"

    Presented by Amanda Stubbs, MIT, Functional Inorganic & Organic Materials

    Friday, March 22, 2019, 9:30 am
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Partial substitution of ZnII by MnII in Zn4O-(terephthalate)3 (MOF-5) leads to a distorted all-oxygen ligand field supporting a single MnII site, whose structure was confirmed by Mn K-edge X-ray absorption spectroscopy. The MnII ion at the MOF-5 node engages in redox chemistry with a variety of oxidants. With tBuSO2PhIO, it produces a putative MnIV-oxo intermediate, which upon further reaction with adventitious hydrogen is trapped as a MnIII−OH species. Most intriguingly, the intermediacy of the high-spin MnIV−oxo species is likely responsible for catalytic activity of the MnII-MOF-5 precatalyst, which in the presence of tBuSO2PhIO catalyzes oxygen atom transfer reactivity to form epoxides from cyclic alkenes with >99% selectivity. These results demonstrate that MOF secondary building units serve as competent platforms for accessing terminal high-valent metal−oxo species that consequently engage in catalytic oxygen atom transfer chemistry owing to the relatively weak ligand fields provided by the SBU.
19. NSLS-II Friday Lunchtime Seminar

    "Results to date on the elimination of Insertion Device Motion control problems by the NSLS-II Insertion device working group"

    Presented by John Escallier, NSLS-II

    Friday, March 15, 2019, 12 pm
    NSLS-II Bldg. 744 Room 156

    Hosted by: Ignace Jarrige

    Control of Insertion Device gap motion by the use of the Delta Tau control platform requires a good understanding of several disciplines simultaneously. Physics, magnetics, mechanics, electronics, software, and control theory are all specialties needed to establish full control of the gaps. The ID working group is comprised of individuals who specialize in one or more of these disciplines, and have been quite successful at attacking and solving multiple issues related to the IVU devices. Improvements in accuracy and control have exceeded close to two orders of magnitude, while simultaneously keeping focus towards the eventual use of step and fly scanning of the gap in synchronous motion with other devices. As work on the first vendor's devices begins to ramp to completion, the group effort is being directed towards work on EPU's. This seminar will detail several of the problems encountered, how they were solved, and where the future lies.
20. NSLS-II Colloquium

    "Challenges of Future Very Short Wavelength X-ray Free-Electron Lasers"

    Presented by Bruce Eric Carlsten, Los Alamos National Laboratory

    Thursday, March 14, 2019, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: John Hill

    Future X-ray Free-Electron Lasers (XFELs) will produce coherent X-rays with energies greater than 20 keV, which will require electron beams with lower laboratory emittances and relative energy spreads than those in current XFELs such as LCLS or the European XFEL. To satisfy this requirement, electron beam energies will need to be higher than in current XFEL designs if conventional accelerator architectures are used, leading to increased construction and operation costs. To provide design margin for these future XFELs at the lowest possible electron beam energies, novel schemes may be employed to suppress or eliminate the present limitations in XFEL performance. This talk will describe the dominant electron-beam instabilities and other effects (coherent synchrotron radiation, undulator resistive wall wakes, microbunch instability, and intrabeam scattering) and will describe a novel accelerator architecture to suppress the worst effects from them. Design trades to improve performance at lower beam energies will also be described. The baseline parameters for the proposed XFEL at Los Alamos (the MaRIE XFEL, designed to have an X-ray energy of 42 keV) will be used to illustrate these effects.
21. NSLS-II Friday Lunchtime Seminar

    "Dynamic Investigations of functional proteins using synchrotron radiation and gold nano-crystals at SPring-8"

    Presented by Hiroshi Sekiguchi, SPring8, Japan

    Friday, March 8, 2019, 12:30 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    In addition to the static crystallographic information regarding a 3D structure of proteins, dynamic information regarding a protein's conformational changes would be helpful in elucidating the molecular mechanisms that regulate protein functions, such as ion channel gating and ligand-induced receptor activation. Such local and dynamic information can be obtained using optical microscopy with recently developed single molecule techniques, and we think that the technique with synchrotron X-rays would be more powerful technique because of its brilliance, its short wavelength of light, and its transparency. Small-angle X-ray scattering (SAXS) is one of well-established technique to investigate the nanoscale structure of protein under physiological conditions and structural changes in response to various external conditions and we have probed a compact intermediate state of calmodulin in the process of target binding [1,2] etc. And we have proposed a single molecule technique that utilizes synchrotron X-rays to monitor the internal motions of a single protein. We call it diffracted X-ray tracking (DXT) and it can detect atomic-scale dynamic motion of the protein at the single molecular level with several tens of microseconds time resolution [3]. In DXT, a target protein is labeled with a nanocrystal with a size of several tens of nanometers and the motions of the nanocrystal coupled with the protein's motions are recorded as the trajectories of diffraction spots from the nanocrystal [4-6]. At the seminar, we will present recent progress of such investigation for biomolecules at SPring-8 [7].
22. NSLS-II Friday Lunchtime Seminar

    "A "coherent" picture of (some) Quantum Materials"

    Presented by Claudio Mazzoli, BNL / NSLS-II

    Friday, March 8, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Quantum Materials are attracting an increasing level of attention in order to understand and fully exploit their peculiar properties for innovative potential applications. The investigation of their relevant electronic phases, their dynamics and their coherence length scales is key to produce a consistent microscopic picture of their functionalities and response to external stimuli. In my talk, I will present some recent investigation on quantum materials performed at CSX (23-ID-1), focusing on their electronic order parameters and interactions, inhomogeneity and time evolution. Examples will include charge ordering in cuprate HTSC, magnetic ordering in artificial patterned samples and nickelates, exotic magnetic phases in multilayers.
23. NSLS-II Friday Lunchtime Seminar

    "Non-magnetic gap in the topological insulators"

    Presented by Turgut Yilmaz, NSLS-II

    Friday, March 1, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    In this talk, I will introduce the electronic structure of Cr-doped Bi2Se3 / pristine Bi2Se3 heterostructure grown by molecular beam epitaxial method. We realized that such heterostructure provides sharper electronic states in angle resolved photoemission experiments. This promotes a new strategy to study the impact of impurities on the surface states of topological insulators. Furthermore, I will show that the apparent gap at the Dirac point of topological insulators in the non-magnetic state is indeed formed by the resonant states. We confirm this by performing the first principle band structure calculation and angle resolved photoemission spectroscopy with on and off-resonant photon energies.
24. NSLS-II Friday Lunchtime Seminar

    "Formation and dynamics of organo-mineral associations in redoximorphic soils"

    Presented by Selina Tenzer, University of Hohenheim, Germany

    Friday, February 22, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Dissolved soil organic matter (SOM) hinders the crystal growth of Fe and Mn oxides but promotes the formation of metal-OM complexes. The strength of the interactions between SOM and the Fe(O,OH)6-octahedra depends, besides pH and ionic strength, on the available functional groups. We investigate the formation of oxides under alternating redox conditions in the presence of two isotopically labelled organic model substances: vanillin (lignin component with a reactive phenol group) and alanine (amino acid with a carboxyl and an amino group). Combining XRF, µXANES and µXRD at 5-ID will allow to identify Fe and Mn oxides, describe their crystallinity and estimate the importance of organic forms of Fe and Mn. Later, we will study the spatial distribution of vanillin and alanine across mineral surfaces by NanoSIMS.
25. NSLS-II Friday Lunchtime Seminar

    "Magneto-electric waves in f-electron magnets"

    Presented by Nicolas Gauthier, Stanford University & SLAC

    Friday, February 15, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    The intertwining of electric, magnetic and structural degrees of freedom in materials is at the heart of novel strongly correlated phases such as magnetoelectric multiferoicity, superconductivity and heavy fermion ground states. Isolating the contributions of dierent degrees of freedom and characterizing their interplay are fundamental aspects to understand such unconventional phases. The multipolar expansion of the electronic conguration provides a powerful framework to attain this objective. As an example, I will present how we can reveal the role of electric quadrupole moments by measuring magnetic dipolar waves with neutron scattering in the frustrated magnet SrDy2O4. Our results indicate that electric eects of the 4f-electrons can dominate over the magnetism in insulators and this encourages a reassessment of the description of rare-earth based magnets with unconventional properties.
26. NSLS-II Collquium

    "Resonant x-ray scattering from soft materials as a probe of molecular orientation fluctuations at the nanoscale"

    Presented by Noel A. Clark, University of Colorado, Boulder

    Thursday, February 14, 2019, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: John Hill

    Orientation fluctuations are ubiquitous features of soft materials on length scales ranging from nanometers in the rotational dynamics of single molecules, to the macroscopic deformation of local orientational order in liquid crystals, polymers, and biomaterials. Here we present the application of depolarized resonant soft x-ray scattering (DRSoXS) as a selective probe of molecular orientation fluctuations at the nanoscale. This technique is demonstrated by determination of the wavevector spectrum of thermally generated collective reorientations in a nematic liquid crystal using Carbon K??-edge resonant scattering (incident wavelength = 4.4nm). DRSOXS uniquely reveals transient, short-range heliconical molecular assemblies and their pretransitional development, as ordering into a chiral three-dimensional helical state is approached.
27. NSLS-II Friday Lunchtime Seminar

    "Rechargeable Sodium-Ion Batteries"

    Presented by Kyung-Wan Nam, Dongguk University, Seoul, Korea, Republic of (South)

    Friday, February 8, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    Rechargeable sodium-ion batteries (SIBs) are now attracting special attention with a great cost advantage over rechargeable lithium-ion batteries (LIBs) especially in the field of large-scale applications. For the successful development of the SIBs, it is imperative to find new cathode and anode materials with high capacity, high power, and long cycle life. With this perspective, we have examined the electrochemical properties of O3-layer structured oxides, Na3M(II)2M(V)O6, with a honeycomb ordering of M(II) and M(V) in the metal layer for the cathode material in SIBs.[1] One of this class materials, Na3Ni2BiO6, can reversibly deliver specific discharge capacities of up to 109 mAh/g with very flat voltage plateaus ~3.5V vs. Na/Na+. Structural changes occurring during charging/discharging investigated by using in situ X-ray diffraction (XRD) are correlated with its long cycle life. Long and short-range structure changes at various state of (dis)charge have been also probed ex-situ using combined synchrotron-based high-resolution X-ray powder diffraction (HRPD) and extended X-ray absorption fine structure (EXAFS). Some of its derivatives with increased redox voltages will also be presented. For the anode materials, various compositions of transition metal oxides including Ti and Fe elements having tunnel based structures (single- and double- tunnels) are explored as rechargeable SIBs.[2] Detailed electrochemical results combined with structural characterization will be presented in the seminar. References: [1] D.S. Bhange, G. Ali, D.-H. Kim, D.A. Anang, T.J. Shin, M.G. Kim, Y.-M. Kang, K.Y. Chung, K.-W. Nam, J. Mat. Chem. A 5 (2017) 1300-1310. [2] D.S. Bhange, G. Ali, J.-Y. Kim, K. Y. Chung, K.-W. Nam, J. Power Sources 366 (2017) 115-122.
28. NSLS-II Friday Lunchtime Seminar

    "Phase Transition Kinetics of Close-Packed Block Copolymer Micelles"

    Presented by Sangwoo Lee, Rensselaer Polytechnic Institute, Troy, NY

    Friday, February 1, 2019, 12 pm
    NSLS-II Bldg. 743 Room 156

    Hosted by: Ignace Jarrige

    In the past decades, the structures of spherical particle packing have been intensively investigated to understand the origin of materials structures and associated properties. However, despite its equal importance, the phase transformation kinetics of spherical particles has been relatively poorly understood. We investigated close-packed structures of spherical block copolymer micelles induced by rapid cooling of disordered micelles using small angle X-ray scattering experiments conducted at the 11-CMS and 12-SMI lines. We found that depending on the depth of quenching, disordered block copolymer micelles self-assemble into three different close-packed structures: face-centered cubic (fcc), random stacking of hexagonal-close packed layers (rhcp), and hexagonal-close-packed (hcp) structures as the depth of temperature quenching increases. Cooling and heating of these close-packed micelle solutions reveal that the hcp and rhcp structures are long-lasting metastable structures that eventually transform to stable fcc. Close-inspection of the 2D small angle X-ray scattering patterns shows that the formation of these metastable structures is correlated with the size of crystallites. The Laplace pressure is attributed to the origin of the formation of the metastable structures.
29. NSLS-II Friday Luncheon Seminar

    "EDRIXS: An open source toolkit for simulating spectra of resonant inelastic x-ray scattering"

    Presented by Yilin Wang, Condensed Matter Physics & Material

    Friday, January 25, 2019, 12 pm
    NSLS-II, Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    In this talk, we present an open source toolkit (dubbed EDRIXS) to facilitate the simulations of RIXS spectra of strongly correlated materials based on exact diagonalization (ED) of certain model Hamiltonians. The model Hamiltonian can be from a single atom, small cluster or Anderson impurity model, with model parameters from density functional theory plus Wannier90 or dynamical mean-field theory calculations. The spectra of x-ray absorption spectroscopy (XAS) and RIXS are then calculated using Krylov subspace techniques. This toolkit contains highly efficient ED, XAS and RIXS solvers written in modern Fortran 90 language and a convenient Python library used to prepare inputs and set up calculations. We first give a short introduction to RIXS spectroscopy, and then we discuss the implementation details of this toolkit. Finally, we show several examples to demonstrate its usage.
30. NSLS-II Friday Lunchtime Seminar Series

    "Computer Vision and new areaDetector features"

    Presented by Kazimierz Gofron, NSLS-II

    Friday, January 18, 2019, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige
31. NSLS-II Colloquium Series

    "Superconductivity: Where we are and where we are going"

    Presented by Prof. Robert Cava, Princeton University, NJ

    Thursday, December 13, 2018, 4 pm
    Hamilton Seminar Room, Bldg. 555

    Hosted by: John Hill

    The discovery of superconductivity, the transmission of electrical current with zero energy loss, recently passed its 100th anniversary. This truly remarkable property of matter, found at cryogenic temperatures, has made its way into a variety of important uses in modern society, but nature has not yet given us the ultimate practical material that will change the world through its lossless transmission of electrical energy over long distances. Research on this complex problem in materials science persists in the world at many levels, and progress is continuously made on both scientific and practical fronts, in spite of the impatience that is often displayed by both the scientific and lay public. In this talk I will briefly describe where we are in this field, and how we got here, and describe the vision that some have had for where we should be going. Because my personal research is in the discovery of new superconducting materials, only one facet among the larger set of fundamental and practical issues currently under study, the talk will be given from that perspective.
32. NSLS-II Friday Lunchtime Seminar

    "Magnetic skyrmions at room temperature - statics, dynamics, and high resolution imaging"

    Presented by Dr. Felix Buttner, Dept of Mat Sci & Eng , MIT

    Friday, December 7, 2018, 12 pm
    NSLS-II Bldg 743 Room 156

    Hosted by: Ignace Jarrige

    Magnetic skyrmions are the smallest non-trivial entities in magnetism with great potential for data storage applications. These chiral and topological quasi-particles furthermore exhibit fascinating static and dynamical properties that render them the ideal candidates to study new physics in high spin-orbit coupling materials. In this talk, I will first give a general introduction to the field of skyrmionics and the fundamental properties of skyrmions that derive from their energetics. I will then discuss various ways of creating and stabilizing room-temperature skyrmions experimentally, as well as how we can move them and observe their topological dynamics via high resolution time-resolved x-ray imaging. I will conclude with perspectives of future research in this field and related areas.
33. NSLS-II Friday Lunchtime Seminar

    "A Novel Stripe Phase in Bi-2212 Cuprate"

    Presented by Yang Ding, Center for High Pressure Science & Technology Advanced Research, China

    Friday, November 30, 2018, 12 pm
    NSLS-II Bldg 743 Room 156

    Hosted by: Ignace Jarrige

    High-temperature superconductivity (HTSC) is one of the most important discoveries at contemporary condensed matter physics. However, its mechanism is still unclear. One way to approach this problem is to search for the controlling parameters of HTSC transition temperature Tc. In this presentation, we will introduce a novel type stripe phase in Bi2212 that is revealed by nano-imaging technique. Intriguingly, the evolution of the stripe phase is in coincidence with the change of Tc, which implies a correlation between the Tc and the optimal inhomogeneity in the cuprate.
34. NSLS-II Seminar

    "Structure/Properties of Thin Film Composite Membranes for Water Purification"

    Presented by Christopher M. Stafford, NIST, Gaithersburg, MD

    Tuesday, November 20, 2018, 11 am
    NSLS-II Bldg. 744

    Hosted by: Ben Ocko

    Access to sustainable sources of clean water is critical to manufacturing, agriculture, energy production, public health, and national security. One prominent technology for meeting this need is membrane-based separations of water and dissolved contaminants/solutes via nanofiltration and reverse osmosis. This field is dominated by polymer-based membranes and has relied on complex, empirically optimized chemistries and structures based on material selections made decades ago. The resulting processes are energy intensive and suffer from limited performance lifetimes. We are bringing our deep expertise in measurement science and polymer science to address this critical technology, specifically by establishing fundamental structure/property relationships that correlate membrane topology and dynamics to membrane performance. In this talk, I will describe our recent efforts in synthesizing model membrane materials based on molecular layer-by-layer deposition of aromatic polyamide networks, as well as our measurements of swelling, crosslink density and mechanics of both model and commercial membrane materials. This understanding will enable industry to develop and manufacture next generation, energy-efficient membrane materials.
35. NSLS-II Friday Lunchtime Seminar

    "Delivering Focused, Rapidly Tunable, Stable Monochromatic X-Rays to the GSECARS APS 13-ID-E Microprobe Endstation"

    Presented by Peter J. Eng, CARS and JFI, University of Chicago

    Friday, November 9, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    With the APS-U scheduled for 2023 GSECARS, is designing and testing enhancements to beamline instrumentation to optimize the benefits of this upgraded source. The sector 13-ID-E microprobe endstation studies a wide range of environmental, earth and planetary problems, requiring a rich array of techniques and instrumentation. Central to the success of this program is the insertion device and the x-ray optics that produce, monochromate and focus the beam on the sample. All aspects of this system are under review. Design efforts are focused on 1) managing the increased total power and power density of the APS-U undulator source; 2) improved beam and sample stability; 3) improved focusing optics; and 4) rapid and high duty cycle scanning of the incident beam energy. This is an ongoing development effort with a number of enhancements schedule to be installed in the 1st quarter of 2019. Other components are in the design or prototype phase, drawing on collaboration between universities, national labs and industry.
36. NSLS-II Friday Lunchtime Seminar

    "Materials Tribology: An Application-Driven Field with Rich Opportunities for Fundamental Studies of Surface Chemistry, Physics, Structure"

    Presented by Brandon A. Krick, Department of Mechanical Engineering and Mechanics, Lehigh University

    Friday, November 2, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    The significant economic (~3-6% of developed countries GDP) and environmental (several percent of our annual energy consumption) impacts of friction and wear make tribology is an important, application-driven field. However, there is an opportunity and need for inherently fundamental studies on surface chemistry, physics and structure to elucidate fundamental mechanisms for friction and wear. The non-equilibrium and transient nature of shear-induced changes caused by contacting surfaces in relative motion requires both in situ and ex situ advanced characterization techniques; many of these only available at the light source at Brookhaven. A brief overview of shear-induced (sliding friction/wear) alterations of surfaces will be presented for material systems including: - environmental and tribochemistry molybdenum disulphide based coatings for space applications - shear-induced band bending in GaN - mechanochemistry of polymer nanocomposites
37. NSLS-II Friday Lunchtime Seminar

    "Thai heritage glasses studied by synchrotron radiation"

    Presented by Dr. Wantana Klysubun, Synchrotron Light Research Institute, Thailand

    Friday, October 26, 2018, 12 pm
    NSLS-II Bldg. 744 Rm 156

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

    "RIXS study of the charge and magnetic evolution in La2-xCexCuO4 combi-film"

    Presented by Xuerong Liu, Shanghai Tech University, China

    Friday, October 19, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    Different from the simple one-band Hubbard model prediction, it has been recognized that the cuprate superconductors are electron-hole asymmetric. Recent RIXS work on the electron-doped Nd2-xCexCuO4 by K. Ishii et al. [1] and W. S. Lee et al. [2] reported a hardening of the spin excitations and the emergence of a charge excitation mode. Both these observations are in distinct contrast to that reported on the hole doped side, and brought attention again to the profound electron-hole asymmetry issue in the cuprates. Taking the advantage of a La2-xCexCuO4 combi-film, namely a film with large range doping gradient distribution, we studied the evolution of the charge and magnetic excitations from optimal- to over-doping systematically in fine steps. Our results establish the universality of the previous observation for the electron-doped cuprates. And more importantly, the doping dependent evolutions show that the magnetic and charge excitations are not the two faces of a coin. Rather, the spin-correlation roots in the short range correlation, and the charge-fluctuation stems from long range Coulomb interaction. [1] K. Ishii et al, Nat. Commun. 5, 3714 (2014). [2] W. S. Lee et al, Nat. Phys. 10, 883 (2014).
39. NSLS-II Friday Seminar Series

    "Chasing Protons in Lithium Batteries"

    Presented by Zonghai Chen, Argonne National Laboratory

    Friday, October 12, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    Nickel-rich lithium transition metal oxides have been recently considered as one of most promising cathode materials for high energy density lithium-ion batteries. However, the instability of the cathode electrolyte interface has been the major technological barrier for the development of nickel-rich cathodes. The early research has simply assigned this interfacial instability to the electrochemical oxidation of the commonly used carbonate solvents without much discussion on the nature of the parasitic reactions. A proprietary high precision electrochemical system was built in-house to quantitatively measure the rate and kinetics of the side reactions between the delithiated cathode and the non-aqueous electrolyte. Our results clearly indicated the dominant chemical reaction within the working potential window is the chemical, not electrochemical, reaction between the intermediate phase of cathode and the electrolyte, generating locally concentrated protons at the surface of the cathode materials. Figure 1 shows a generic mechanism of parasitic reactions occurring at the interface of cathode materials. Additional help from advanced characterization tools, such as synchrotron probes, will be also be discussed.
40. NSLS-II Colloquium Series

    "Biophysical Studies of an RNA Virus particle and its Maturation: Insights into an Elegantly Programmed Nano-machine"

    Presented by John E. (Jack) Johnson, Department of Integrative Structural and Computational Biology, The Scripps Research Institute

    Thursday, October 11, 2018, 4 pm
    Large Seminar Room, Bldg. 510

    Hosted by: John Hill

    Nudaurelia Capensis ? Virus (N?V) is a eukaryotic, quasi-equivalent, RNA virus, with a T=4 surface lattice, where maturation is dramatic (a change in particle size of 100Å) and is novel in that it can be investigated in vitro. Here we use X-ray crystallography, biochemistry, Small Angle X-ray Scattering, and electron cryo-microscopy and image reconstruction (CryoEM), to characterize maturation intermediates, an associated auto-catalytic cleavage, the kinetics of morphological change and to demonstrate that regions of N?V subunit folding are maturation-dependent and occur at rates determined by their quasi-equivalent position in the capsid. Matsui, T., Lander, G. C., Khayat, R., and Johnson, J. E. 2010. Subunits fold at position-dependent rates during maturation of a eukaryotic RNA virus. Proc Natl Acad Sci U S A 107:14111-5. Veesler, D., and Johnson, J.E. 2012. Virus Maturation. Annual review of biophysics 41:473-496. Doerschuk, P. C., Gong, Y., Xu, N., Domitrovic, T., and Johnson, J. E. 2016. Virus particle dynamics derived from CryoEM studies. Curr Opin Virol 18:57-63.
41. NSLS-II Friday Seminar

    "Highly Active and Stable Carbon Nanosheets Supported Iron Oxide for Fischer-Tropsch to Olefins Synthesis"

    Presented by Congjun Wang, National Energy Technology Laboratory, Pittsburgh, PA

    Friday, October 5, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    Light olefins production utilizes the energy intensive process of steam cracking. Fischer-Tropsch to olefins (FTO) synthesis potentially offers a more sustainable alternative. Here we show a promising FTO catalyst comprised of iron oxide nanoparticles supported on carbon nanosheets (CNS) fabricated from the carbonization of potassium citrate, which incorporates well dispersed K-promoter throughout the CNS support. This catalyst exhibits, to the best of our knowledge, the highest iron time yield of 1790–1990 μmolCO/gFe•s reported in the literature, 41% light olefins selectivity, and over 100 hours stable activity, making it one of the best performing FTO catalysts. Detailed characterization, including synchrotron X-ray spectroscopy, illustrates that the CNS support facilitates iron oxide reduction to metallic iron, leading to efficient transformation to the active iron carbide phase during FTO reaction. Since K is a commonly used promoter, our K-promoted CNS support potentially has broad utility beyond the FTO reactions demonstrated in the current study.
42. NSLS-II Friday Lunchtime Seminar

    "Shape-Symmetry Incommensurate Polymer Crystals Directed by Liquid-liquid Interface"

    Presented by Prof. Christopher Li, Department of Materials Science and Engineering, Drexel University

    Friday, September 28, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    Crystallization is ubiquitous in nature and semicrystalline polymers are of crucial importance in our daily life. Compared with small molecules, polymers crystallize via a more complex pathway because of their long chain nature and various metastable states associated with polymer crystals. In this talk, I will show that this complex conformational change of polymer chains upon crystallization can be employed to design and fabricate functional nanomaterials. We will focus on crystallization directed by liquid/liquid interface. Not only can this type of dynamic interface direct the crystallization pathway, it can also alter chain packing in the final crystals, leading to intriguing macroscopic properties. In particular, curved interface, which is incommensurate with the classical translation symmetry, frustrates chain packing, and induced defect formation, a topic that will be discussed in the context of recently reported spherical crystallography.
43. NSLS-II Friday Luncheon Seminar

    "X-ray sparse-angle Bragg ptychography"

    Presented by Dr. Peng Li, Institut Fresnel (CNRS), Marseille, France

    Friday, September 21, 2018, 12:30 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    X-ray Bragg ptychography is a scanning coherent diffraction imaging microscopy technique that can produce 3D maps of the crystalline structure of an extended nanostructured crystal at about 10nm resolution. With sparse-angle Bragg ptychography, the 3D maps can be extracted from an extremely undersampled data-set. This new strategy substantially reduces the acquisition time and mitigates problems, linked to radiation damage and instabilities, faced by conventional Bragg ptychography. However, the success of the image reconstruction is based on a good knowledge of the probe, whose uncertainties degrade the object reconstruction. In this talk, we solve this problem by proposing a simultaneous reconstruction of the probe and object functions. This is based on a strong but natural constraint of the probe properties. We demonstrate our approach on a He-implanted poly-crystalline Tungsten sample measured at ID01-ESRF. These findings open new possibilities for this imaging technique.
44. NSLS-II Seminar

    "X-ray spectroscopy of transition metal oxides"

    Presented by Frank de Groot, Utrecht University, Netherlands

    Thursday, August 23, 2018, 11 am
    NSLS-II Building 744 Room 156

    Hosted by: Lisa Miller

    Some new developments in x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) will be discussed. An introduction is given of XAS, including the oxygen K edge, metal K edge and metal L edge [1,2]. The main part of the talk deals with resonant inelastic x-ray scattering (RIXS) In 2p3d RIXS one scans through the 2p XAS edge and measures the low energy excitations, including phonons, magnons, dd-excitations and charge transfer. The 100 meV resolved 2p3d RIXS spectra of ruby (Cr3+ in Al2O3), Fe3O4 and LaCoO3 will be discussed [3,4]. The present experimental resolution of 30 to 100 meV allows the detailed observation of the electronic structure, including the determination of crystal field parameters, covalency parameters and spin-orbit coupling, but also the momentum dependence of magnons and other low energy excitations. Related to the RIXS measurements is the analysis of Fluorescence yield (FY) detected x-ray absorption spectra (XAS), including the intrinsic deviations of FY-XAS spectral shape from the XAS spectrum that is important for measurements with x-ray free electron lasers [5,6]. [1] Core Level Spectroscopy of Solids Frank de Groot and Akio Kotani (Taylor & Francis CRC press, 2008) [2] Download the x-ray spectroscopy simulation software at http://www.anorg.chem.uu.nl/CTM4XAS/ [3] Huang et al. Nature Comm. 8, 15929 (2017). [4] Tomiyasu et al. Phys. Rev. Lett. 119, 196402 (2017) [5] F.M.F. de Groot, Nature Chemistry 4, 766 (2012) [6] Mitzner et al. J. Phys. Chem. Lett. 4, 3641 (2013)

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

1. Teacher Training: Exploring Proteins with a New Light

   July 1-3, 2019
2. 11th International Conference on Inelastic X-ray Scattering (IXS2019)

   June 23-28, 2019
3. 4th International Conference on Resonant Elastic X-ray Scattering (REXS 2019)

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

   May 29-31, 2019
5. 2019 NSLS-II & CFN Joint Users' Meeting

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

   March 8, 2019
7. LiX Solution Scattering Workbench

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

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

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

    September 17-19, 2018
11. 10th International Workshop on X-ray Radiation Damage to Biological Samples

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

    June 24-28, 2018
13. 2018 NSLS-II and CFN Users' Meeting

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

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

    October 30 - November 1, 2017
16. 2017 NSLS-ll and CFN Users' Meeting

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

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

    November 2-4, 2016
19. 14th International Conference on Surface X-ray and Neutron Scattering (SXNS14)

    July 10-14, 2016
20. 2016 NSLS-ll and CFN Users' Meeting

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

    November 5-7, 2015
22. 8th International Workshop on Infrared Microscopy and Spectroscopy using Accelerator Based Sources

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

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

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

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

    July 13-14, 2015
27. 12th International Conference on Synchrotron Radiation Instrumentation (SRI 2015)

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

    May 21-22, 2015
29. 2015 NSLS-II & CFN Joint Users' Meeting

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

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

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

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

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

    May 19-21, 2014
35. X9 SAXS Workbench

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

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

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

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

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

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

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

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

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

    May 8-10, 2013
45. RapiData 2013

    April 21-26, 2013
46. X9 SAXS Workbench

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

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

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

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

    November 8-10, 2012
51. X9 SAXS Workbench

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

    September 17-18, 2012
53. X9 SAXS Workbench

    June 21-24, 2012
54. Crystallography Workbench

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

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

    June 5-8, 2012
57. 2012 NSLS/CFN Joint Users' Meeting

    May 21-23, 2012
58. Operando IV

    4th International Congress on Operando Spectroscopy

    April 29 - May 3, 2012
59. 4th International Congress on Operando Spectroscopy

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

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

    March 27-30, 2012
62. X9 SAXS Workbench

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

    November 3-5, 2011
64. X9 SAXS Workbench

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

    August 12, 2011
66. Materials Diffraction Suite Workshop

    July 18-20, 2011
67. 2011 NSLS/CFN Users' Meeting

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

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

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

    October 7-14, 2010
71. 2010 Joint NSLS and CFN Users Meeting

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

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

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

    July 20-23, 2009
75. INCREASE Workshop

    Interdisciplinary Consortium for Research and Educational Access in Science and Engineering

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

    May 20-22, 2009
77. 2009 NSLS / CFN Users' Meeting

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

    April 6-7, 2009