BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//IXAS: The International X-ray Absorption Society - ECPv6.15.15//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://xrayabsorption.org
X-WR-CALDESC:Events for IXAS: The International X-ray Absorption Society
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:America/Los_Angeles
BEGIN:DAYLIGHT
TZOFFSETFROM:-0800
TZOFFSETTO:-0700
TZNAME:PDT
DTSTART:20190310T100000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0700
TZOFFSETTO:-0800
TZNAME:PST
DTSTART:20191103T090000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0800
TZOFFSETTO:-0700
TZNAME:PDT
DTSTART:20200308T100000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0700
TZOFFSETTO:-0800
TZNAME:PST
DTSTART:20201101T090000
END:STANDARD
BEGIN:DAYLIGHT
TZOFFSETFROM:-0800
TZOFFSETTO:-0700
TZNAME:PDT
DTSTART:20210314T100000
END:DAYLIGHT
BEGIN:STANDARD
TZOFFSETFROM:-0700
TZOFFSETTO:-0800
TZNAME:PST
DTSTART:20211107T090000
END:STANDARD
END:VTIMEZONE
BEGIN:VTIMEZONE
TZID:UTC
BEGIN:STANDARD
TZOFFSETFROM:+0000
TZOFFSETTO:+0000
TZNAME:UTC
DTSTART:20190101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200611
DTEND;VALUE=DATE:20200612
DTSTAMP:20260718T192052
CREATED:20200514T015818Z
LAST-MODIFIED:20200617T021645Z
UID:384-1591833600-1591919999@xrayabsorption.org
SUMMARY:Alessandra Leri: XANES Spectroscopy to Illuminate Biogeochemical Cycling of Halogens in Environmental Systems
DESCRIPTION:The halogens chlorine and bromine have high electron affinities and exist in seawater mainly as chloride and bromide anions\, which have generally been considered unreactive in the environment. Using Cl and Br K-edge XANES spectroscopy\, we have measured high concentrations of organo-chlorine and -bromine in naturally degraded particulate organic matter (POM) from oceanic sediment traps. While organobromine speciation in marine POM is exclusively aromatic\, organochlorine is fractionated into aliphatic and aromatic particles that appear in a heterogeneous distribution. The major precursor of sediment trap material is phytoplankton biomass\, the detritus of which under-goes oxidative breakdown as part of the marine carbon cycle. We hypothesized that unsaturated lipid and protein moieties in phytoplankton detritus would be susceptible to halogenation through oxidative degradation mechanisms. Using model experiments\, we showed that algal particulates are readily chlorinated and brominated through various abiotic pathways\, including photochemical and Fenton-like reactions. These processes produce organohalogens in particulate algal detritus at levels exceeding 0.1% by mass. In contrast with the exclusively aromatic organobromine observed in natural marine POM\, the lab-based experiments generate aliphatic organobromine in algal particulates; however\, the aliphatic organobromine produced appears to be labile and susceptible to debromination on relatively short (3-week) timescales under highly oxidizing conditions. These findings have implications for the transformation and stabilization of marine organic carbon prior to sedimentary burial.\nWe have also measured high concentrations of non-volatile organochlorine and -bromine in several varieties of edible kelps. Such compounds are likely to contribute to organohalogen body burden in humans and other organisms.\n \nReferences: \n\nA. Leri\, M. Dunigan\, R. Wenrich\, and B. Ravel (2019). Particulate organohalogens in edible brown seaweeds. Food Chemistry 272\, 126. https://doi.org/10.1016/j.foodchem.2018.08.050\nA. Leri\, L. Mayer\, K. Thornton\, P. Northrup\, M. Dunigan\, K. Ness\, and A. Gellis (2015). A marine sink for chlorine in natural organic matter. Nature Geoscience 8\, 620. https://www.nature.com/articles/ngeo2481\nA. Leri\, L. Mayer\, K. Thornton\, and B. Ravel (2014). Bromination of marine particulate organic matter through oxidative mechanisms. Geochimica et Cosmochimica Acta 142\, 53. https://doi.org/10.1016/j.gca.2014.08.012\nA. Leri and B. Ravel (2014). Sample thickness and quantitative concentration measurements in Br K-edge XANES spectroscopy of organic materials. Journal of Synchrotron Radiation 21\, 623. https://doi.org/10.1107/S1600577514001283\n\n\n 
URL:https://xrayabsorption.org/events/journalclub-alessandra-leri/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200615
DTEND;VALUE=DATE:20200616
DTSTAMP:20260718T192052
CREATED:20200522T142834Z
LAST-MODIFIED:20200617T021815Z
UID:413-1592179200-1592265599@xrayabsorption.org
SUMMARY:Anna Zymakova: Introduction to ELI-Beamlines
DESCRIPTION:Introduction to ELI-Beamlines – a new user facility in the heart of Europe. Status and prospective of ELI X-ray spectroscopy end-station \nImproved access to state-of-the-art facilities is a key element to groundbreaking advances in science. One such facility is the Extreme Light Infrastructure (ELI); a pan-European project of which one pillar (ELI-Beamlines) is located near Prague in Czech Republic. The new facility utilizes ultra-high power lasers in research projects aimed at studying intense light/matter interactions as well as making use of short pulsed lasers to drive secondary X-ray and XUV sources (such as Plasma X-ray sources\, Betatron\, High-order Harmonic generation etc.) and particle accelerators (electrons and ions) for applications in material science\, biomedicine\, laboratory astrophysics etc. The E1 experimental hall at ELI Beamlines houses a few secondary sources that generate beams in wide\, complementary\, energy ranges\, as well as end-stations that will be used for correlative ultrafast experiments. Particularly\, the station for time-resolved experiments with X-rays (TREX) includes diffractometry and spectroscopy setup for pump-probe X-ray experiments. These will use plasma X-ray sources driven by the in-house developed L1-ALLEGRA laser (1kHz\, 100mJ\, <20fs laser pulses @830nm)\, as well as conventional support lasers. The presentation will give a short overview of the ELI project and ELI-Beamlines structure. I will focus on the status and outlook of the x-ray spectroscopy station currently under development for an improved user availability for high demand ultrafast x-ray techniques. \nReferences: \n\nF. Batysta et al.\, Opt. Express 24\, 17843 (2016) https://doi.org/10.1364/OE.24.017843\n\n 
URL:https://xrayabsorption.org/events/journalclub-anna-zymakova/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200618
DTEND;VALUE=DATE:20200619
DTSTAMP:20260718T192052
CREATED:20200522T142943Z
LAST-MODIFIED:20200714T011612Z
UID:415-1592438400-1592524799@xrayabsorption.org
SUMMARY:Anatoly Frenkel:	Machine learning - assisted analysis of material’s structure using XANES and EXAFS spectra
DESCRIPTION:Tracking the structure of functional nanomaterials (e.g.\, metal catalysts) remains a challenge due to the paucity of experimental techniques that can provide atomic-level information for metal species in harsh conditions\, often required for studying chemical transformations. Here we report on the use of X-ray absorption spectroscopy (XANES and EXAFS) and supervised machine learning (SML) for determining the three-dimensional geometry of monometallic and alloy nanoparticles [1]. Artificial neural network (NN) is used to unravel the hidden relationship between the XANES features and material’s geometry [2]. In the case of EXAFS\, NN is used to obtained the partial radial distribution function (PRDF) directly from the spectra [3]. In other words\, we trained computer to learn how to ‘invert” the unknown spectrum and obtain the underlying structural descriptors. Training of the NN was performed by using theoretical spectroscopy codes. These applications are demonstrated by reconstructing the compositional distributions of nanocatalysts from the coordination numbers obtained by NN-XANES\, or from the PRDF obtained by NN-EXAFS. The first applications of these method to the determination of structure of nanocatalysts in reaction conditions will be demonstrated [4-6]. \nReferences: \n\nJ. Timoshenko\, A. I. Frenkel. “Inverting” X-ray Absorption Spectra of Catalysts by Machine Learning in Search of Activity Descriptors. ACS Catalysis (Perspective) 9\, 10192-10211 (2019).  https://pubs.acs.org/doi/10.1021/acscatal.9b03599\nJ. Timoshenko\, D. Lu\, Y. Lin\, A. I. Frenkel. Supervised machine learning-based determination of three-dimensional structure of metallic nanoparticles. J. Phys. Chem. Lett.\, 8\, 5091-5098 (2017). https://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b02364\nJ. Timoshenko\, et al. Artificial neural network approach for characterizing structural transformations by X-ray Absorption Fine Structure spectroscopy. Phys. Rev. Lett. 120\, 225502 (2018). https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.120.225502\nN. Marcella\, Y. Liu\,et al Neural network assisted analysis of bimetallic nanocatalysts using X-ray absorption near edge structure spectroscopy. Phys. Chem. Chem. Phys. (2020) Early view. https://pubs.rsc.org/en/content/articlehtml/2020/cp/d0cp02098b\nJ. Timoshenko\, et al . Probing atomic distributions in mono- and bimetallic nanoparticles by supervised machine learning. Nano Letters 19\, 520-529 (2019). https://pubs.acs.org/doi/10.1021/acs.nanolett.8b04461\nY. Liu\,et al . Mapping XANES spectra on structural descriptors of copper oxide clusters using supervised machine learning. J. Chem. Phys. 151\, 164201 (2019).  https://aip.scitation.org/doi/full/10.1063/1.5126597\n\n\n 
URL:https://xrayabsorption.org/events/journalclub-anatoly-frenkel/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200622
DTEND;VALUE=DATE:20200623
DTSTAMP:20260718T192052
CREATED:20200522T143357Z
LAST-MODIFIED:20200714T011226Z
UID:417-1592784000-1592870399@xrayabsorption.org
SUMMARY:Lijia Liu:	XEOL studies of Light-Emitting Materials
DESCRIPTION:X-ray excited optical luminescence (XEOL) is a photon-in-photon-out process which monitors the visible luminescence emitted from materials upon X-ray excitation. Unlike using low energy excitation source such as UV\, during X-ray excitation\, core electrons are excited and the production of luminescence is a much more complicated process. Because of this\, X-ray excited luminescence can be correlated with the decay process of a specific core electron. In this talk\, I will introduce the fundamental process of XEOL and the unique information it provides\, when combining with X-ray absorption near-edge structure (XANES)\, in revealing the origin of the luminescence. Two materials systems\, nanostructured TiO2 and metal-doped lead halide perovskite\, will be used as examples to demonstrate the XEOL-XANES analysis technique.  \nReferences: \n\nLi et al\, https://doi.org/10.1021/acs.chemmater.5b00363\nMa et al\, https://doi.org/10.1039/c9nr00143c\n\n 
URL:https://xrayabsorption.org/events/journalclub-lijia-liu/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200625
DTEND;VALUE=DATE:20200626
DTSTAMP:20260718T192052
CREATED:20200522T143526Z
LAST-MODIFIED:20200630T151432Z
UID:419-1593043200-1593129599@xrayabsorption.org
SUMMARY:Sara Lafuerza:	 The chemical sensitivity of core-to-core XES in 3d transition metals
DESCRIPTION:K-fluorescence X-ray emission spectroscopy (XES) is receiving a growing interest in all branches of natural sciences to investigate the local spin in 3d transition metal complexes. Unlike the valence-to-core emission lines\, the core-to-core transitions in Kβ (3p to 1s) and Kα (2p to 1s) do not probe the valence shell directly and the chemical sensitivity is thus indirect. In Kβ and Kα emission\, the local spin sensitivity stems from the exchange interaction between the 3p (Kβ) or 2p (Kα) core-hole and the 3d valence shell spin of the transition metal ion\, which is larger for Kβ than Kα [1]. The magnitude of the exchange interaction depends for a given element on the valence shell spin\, which is defined by the metal atom oxidation and spin state within an ionic picture. This is a very crude description of the electronic structure and the influence of covalence in Kβ has been pointed out by several authors [1\,2].\nIn this talk\, the results of a systematic investigation of Kβ and Kα XES spectra measured on a wide range of iron compounds will be presented. More than 30 samples with different oxidation state (+2\, +3\, +4 and mixed-valence)\, spin (high-spin\, low-spin and mixed-spin)\, ligands (fluorides\, oxides\, sulfides\, etc.) or local coordination (octahedral\, tetrahedral) were measured at beamline ID26 of the ESRF synchrotron. We analysed the experimental spectra in terms of commonly used quantitative parameters (Kβ1\,3-first moment\, Kα1-full width half maximum\, and integrated absolute difference –IAD– [3]) and we carefully examined the difference spectra. We also performed multiplet calculations to elucidate the underlying mechanisms that lead to the chemical sensitivity.\nOur results confirm a strong influence of covalency on both Kβ and Kα lines. We establish a reliable spin sensitivity of Kβ XES as it is dominated by the exchange interaction whose variations can be quantified by either Kβ1\,3-first moment or Kβ-IAD and result in a systematic difference signal lineshape. We find an exception in the Kβ XES of Fe3+ and Fe2+ in aqueous solution\, where a new difference spectrum is identified that cannot be explained by scaling the exchange integrals. We explain this with strong differences in orbital mixing between the valence orbitals. This result calls for caution in the interpretation of Kβ XES spectral changes as due to spin variations without careful analysis of the lineshape. For Kα XES\, the smaller exchange interaction together with the influence of other electron-electron interactions make it difficult to extract a quantity that directly relates to the spin. \nReferences: \n\n P. Glatzel and U. Bergmann\, Coord. Chem. Rev. 249\, 65 (2005); https://doi.org/10.1016/j.ccr.2004.04.011 \nC. J. Pollock\, M. U. Delgado-Jaime\, M. Atanasov\, F. Neese and S. De Beer\, J. Am. Chem. Soc. 136\, 9453 (2014); https://doi.org/10.1021/ja504182n\n G. Vankó\, T. Neisius\, G. Molnár\, F. Renz\, S. Kárpáti\, A. Shukla\, and F. M. F. de Groot\, J. Phys. Chem. B 110\, 11647 (2006); https://doi.org/10.1021/jp0615961 \n\n 
URL:https://xrayabsorption.org/events/journalclub-sara-lafuerza-2/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200629
DTEND;VALUE=DATE:20200630
DTSTAMP:20260718T192052
CREATED:20200522T143648Z
LAST-MODIFIED:20200630T151555Z
UID:421-1593388800-1593475199@xrayabsorption.org
SUMMARY:Feng Lin: Ion Reactions to Modulate Solid-State Electrochemistry for Batteries and Electrocatalysis
DESCRIPTION:Ion reactions offer a huge playground for tuning the electronic and crystal properties of inorganic solids for energy applications. Our research focuses on resolving a longstanding question in materials electrochemistry regarding redox active solids: how does the mesoscale chemical distribution influence ion reactions at different length scales? Through manipulating the thermodynamics and kinetics of the ion intercalation chemistry\, our goal is to develop experimental methodologies and establish novel design principles to enhance the electrochemical properties of ion-intercalating solids for batteries and electrocatalysis. Our studies are largely facilitated by synchrotron X-ray spectroscopic and imaging techniques that provide fundamental insights into intercalation chemistries. In this presentation\, we will first highlight our recent progress in understanding and improving electrode materials for lithium and sodium batteries. We design novel synthetic approaches to overcome the surface challenges of oxide cathode materials for high energy density\, high power density and long cycle life. Then\, we will discuss how we make use of interfacial ion reactions to modulate the electronic properties of water splitting electrocatalysts. We will highlight that tailoring the phase segregation at the catalyst-electrolyte interface constitutes a large space for stabilizing catalytic activity. \n 
URL:https://xrayabsorption.org/events/journalclub-feng-lin/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200702
DTEND;VALUE=DATE:20200703
DTSTAMP:20260718T192052
CREATED:20200522T143805Z
LAST-MODIFIED:20200705T154542Z
UID:423-1593648000-1593734399@xrayabsorption.org
SUMMARY:Yuanyuan Li: Multimodal approach for determining the electronic and atomic structure of ceria supported Pt single atoms catalyst
DESCRIPTION:Single atoms catalysts (SACs) have been heavily investigated in the recent years because of their good catalytic properties (especially activity and selectivity) for many chemical reactions [1]. In addition to that\, in SACs\, the supported metals are used with extremely high efficiency compared to their nano counterparts. That is very important for noble metals\, which are naturally scare yet widely used in industry for a vast number of important chemical reactions. Despite of the progress that has been made\, there are fundamental questions remained unaddressed: what is the structure (electronic and atomic) that responsible for the improved catalytic properties? How does the structure respond to the reaction environment? Only by addressing these questions\, are we able to improve synthesis processes to get desired catalysts. \nThe key to address the above-mentioned questions is the capability of characterizing the structure of single atoms catalysts. The challenge originates from: 1) for SACs\, the weight loading of single atoms on the support is usually low\, 2) the heterogeneity of the single atom sites owing to the surface heterogeneity of most solid supports\, and 3) the complex structure of the single atoms system resulted from the strong correlation between the single atoms and the support. This work aimed to address those issues by developing synthesis methods for obtaining homogeneously distributed single atoms with high weight loadings and combining multiple experimental techniques (STEM\, DRIFTS\, XPS\, RIXS\, XAS) with calculation methods to study the electronic and atomic structure of single atoms with the presence of strong metal-support interactions. For demonstration\, the specific system studied here is ceria supported Pt single atoms [2]. \nReferences: \n\nA. Wang\, J. Li\, T. Zhang\, Heterogeneous single-atom catalysis. Nature Reviews Chemistry 2\, 65–81 (2018). https://doi.org/10.1038/s41570-018-0010-1\n\nM. Kottwitz\, Y. Li\, R. M. Palomino\, Z. Liu\, Q. Wu\, G. Wang\, J. Huang\, J. Timoshenko\, S. D. Senanayake\, M. Balasubramanian\, D. Lu\, R. G. Nuzzo\, A. I. Frenkel\, Local structure and electronic state of atomically dispersed Pt on nanosized CeO2 support\, ACS Catalysis 9\, 8738-8748 (2019). https://doi.org/10.1021/acscatal.9b02083\n\n\n 
URL:https://xrayabsorption.org/events/journalclub-yuanyuan-li/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200706
DTEND;VALUE=DATE:20200708
DTSTAMP:20260718T192052
CREATED:20200522T144124Z
LAST-MODIFIED:20200714T011003Z
UID:425-1593993600-1594166399@xrayabsorption.org
SUMMARY:Chris Glover: Australian XAFS: Past\, present\, and a Br-ght future
DESCRIPTION:The Australian XAFS community started from small beginnings and currently\, XAFS is one of the most oversubscribed techniques at the Australian Synchrotron. The community has been fostered by access to facilities; initially the Australian National Beamline Facility (ANBF) at the Photon Factory\, to more recently the XAS beamline at the Australian Synchrotron. The ANBF was a simple and versatile\, non focussed bend magnet beamline\, which was retired in ~ 2010. The XAS beamline is a Wiggler based\, focussed beamline\, with much greater flux and high photon energies\, and has been operational since 2007. User demand has resulted in two new beamlines\, currently under construction at the Australian Synchrotron – the Medium Energy X-Ray Absorption Spectroscopy Beamlines (MEX 1 and 2). These beamlines share a bend magnet\, and are aimed to cover the Tender and medium energy range with differing beamsizes – from microns’s to mm’s. MEX will be equipped with 4 endstations in total\, including a microprobe\, a 5 crystal Rowland circle spectrometer and a custom low energy X-Ray spectrometer. \n\nI this talk\, I will briefly describe the past\, present and the bright future of XAFS in the Australian context. I will briefly summarise the ANBF\, the capabilities and performance of the XAS beamline and highlight the scientific opportunities and complementary nature of the new MEX beamlines.\n \nReferences: \n\nhttps://www.nature.com/articles/srep20350\nhttps://pubs.acs.org/doi/10.1021/cn200097s\nhttps://pubs.acs.org/doi/10.1021/acs.biochem.5b01136\nhttps://www.ansto.gov.au/user-access/instruments/australian-synchrotron-beamlines/x-ray-absorption-spectroscopy\nhttps://www.ansto.gov.au/research/facilities/australian-synchrotron/project-br-ght\n\n 
URL:https://xrayabsorption.org/events/journalclub-chris-glover/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200709
DTEND;VALUE=DATE:20200710
DTSTAMP:20260718T192052
CREATED:20200522T144257Z
LAST-MODIFIED:20200714T010724Z
UID:427-1594252800-1594339199@xrayabsorption.org
SUMMARY:Dooshaye Moonshiram: Electronic and Structural Configurations of Earth-Abundant Water Splitting Catalysts and Spin Crossover Complexes
DESCRIPTION:The solar light-driven splitting of water for hydrogen fuel production is a promising alternative to fossil fuels due to their rapid depletion and concomitant environmental pollution. The design of light-driven devices composed of organic\, inorganic or hybrid materials that can mimic natural photosynthetic processes is extremely desirable. An essential component of such systems is the light-harvesting chromophore\, analogous to the photosynthetic pigments\, which can absorb the energy of the incident photons. Consequently\, the light energy is converted into an electronically excited state for the creation of a charge-separated state that helps to generate the required thermodynamic driving force for subsequent catalytic reactions. \nCommonly used molecular photosensitizers traditionally contain precious and scarce 4d or 5d transition metals such as Platinum\, Ruthenium\, Rhenium or Iridium. However\, over the past decades\, a range of noble metal-free photosensitizers based on earth-abundant metals such as Copper\, Chromium\, and Zinc appeared\, with the aim to bring these light-harvesting molecules into more practical applications. A systematic series novel homo- and heteroleptic Cu(I) photosensitizers based on tetradentate 1\,10-phenanthroline ligands of the type X^N^N^X containing two additional donor moieties in the 2\,9-position (X = SMe or OMe) were designed. Time-resolved X-ray absorption spectroscopy in the picosecond time scale\, coupled with time-dependent density functional theory calculations\, provided in-depth information on the excited state electron configurations. For the first time\, a significant shortening of the Cu-X distance and a change in the coordination mode to a pentacoordinated geometry is shown in the excited states of the two homoleptic complexes. These findings are important with respect to a precise understanding of the excited state structures and a further stabilization of this type of photosensitizers. This talk will further demonstate the reaction pathways of several cobalt and nickel-based hydrogen evolving complexes\, examined in unprecedented detail with picosecond time resolution when coupled with copper and ruthenium-based photosensitizers. Results shown will enable the rational design of molecular hydrogen-evolving photocatalysts that can perform beyond the current microsecond time scale\, and suggest ways in which the ligand structures can be adjusted to facilitate protonation and catalytic efficiency.\n \nReferences: \n\nIglesias et al\, Tracking Light-Induced Excited-State Dynamics…. Chem Eur J 2020 https://doi.org/10.1002/chem.202001393\nMoonshiram et al Tracking Structural and Electronic Configurations… JACS 2016 https://doi.org/10.1021/jacs.6b05680\nGotica et al Spectroscopic Characterization of a Bio-inspired … Chem Eur J 2019 https://doi.org/10.1002/chem.201904934\nRentschler Coordination Behavior of Cu(I) Photosensitizers… Chem Eur J 2019 https://doi.org/10.1002/chem.201905601\n\n 
URL:https://xrayabsorption.org/events/journalclub-dooshaye-moonshiram/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200713
DTEND;VALUE=DATE:20200715
DTSTAMP:20260718T192052
CREATED:20200522T144512Z
LAST-MODIFIED:20200720T012040Z
UID:430-1594598400-1594771199@xrayabsorption.org
SUMMARY:Wantana Klysubun: XAS capability and science at the Thailand synchrotron
DESCRIPTION:
URL:https://xrayabsorption.org/events/journalclub-wantana-klysubun/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200716
DTEND;VALUE=DATE:20200717
DTSTAMP:20260718T192052
CREATED:20200621T134547Z
LAST-MODIFIED:20200720T012215Z
UID:486-1594857600-1594943999@xrayabsorption.org
SUMMARY:Hao Yuan:  Ptychography and 4D imaging by spectro-ptycho-tomography
DESCRIPTION:Coherent X-ray scattering (diffraction) methods will be key to exploiting the high coherent flux of 4th generation synchrotron sources. Ptychography is a coherent diffraction technique that allows rapid\, reliable inversion of arrays of diffraction images into real space images by using overlapping spatial areas to constrain the reconstruction [1]. While ptychography is quite well developed in the hard X-ray regime and in electron and optical microscopy\, the implementation of soft X-ray ptychography is in its infancy. Soft X-ray ptychography is a coherent diffraction imaging technique readily implemented in Scanning Transmission X-ray Microscopy (STXM) [2]. 4D imaging by soft X-ray ptychography – chemically specific\, quantitative 3D mapping of nanostructures can provide insight into the physical and chemical properties. By measuring spectro-ptycho-tomography – 2D ptychographic images at multiple photon energies and multiple tilt angles – 3D chemical distribution can be derived [3]. \nReferences: \n\nPfeiffer F. X-ray ptychography. Nature Photonics\, 2018\, 12(1): 9-17. https://doi.org/10.1038/s41566-017-0072-5\n\nShapiro D A\, Yu Y S\, Tyliszczak T\, et al. Chemical composition mapping with nanometre resolution by soft X-ray microscopy. Nature Photonics\, 2014\, 8(10): 765-769. \nWu J\, Zhu X\, Shapiro D A\, et al. Four-dimensional imaging of ZnO-coated alumina aerogels by scanning transmission X-ray microscopy and ptychographic tomography. The Journal of Physical Chemistry C\, 2018\, 122(44): 25374-25385. https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.8b07363\n\n\n 
URL:https://xrayabsorption.org/events/journalclub-hao-yuan/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200720
DTEND;VALUE=DATE:20200722
DTSTAMP:20260718T192052
CREATED:20200621T134914Z
LAST-MODIFIED:20200727T030541Z
UID:488-1595203200-1595375999@xrayabsorption.org
SUMMARY:Li Song: Soft X-ray endstaions at the Hefei Light Source and some applications of XAS
DESCRIPTION:Hefei Light Source (HLS) is the first dedicated synchrotron radiation facility in China with electron ring energy of 0.8 Gev\, which is located on the West Campus of the University of Science and Technology of China (USTC). With the completion of twice constructions and recent upgradation\, HLS become a fully upgraded soft X-ray synchrotron radiation facility\, now operating ten experimental stations (Infrared Spectroscopy and Microspectroscopy\, Combustion and Flame\, Mass Spectrometry\, Soft X-ray Microscopy\, Spectral Radiation Standard and Metrology\, Atomic & Molecular Physics\, Photoemission Spectroscopy\, Catalysis and Surface Science\, X-Ray Magnetic Circular Dichroism\, Angle-resolved Photoemission Spectroscopy) [1]. The well-designed beamlines and experimental stations at HLS\, together with the Shanghai synchrotron Radiation Facility and the Beijing Synchrotron Radiation Facility\, allow us to perform cutting edge scientific experiments. Here\, I will briefly introduce the soft X-ray endstations at HLS\, and present our recent studies based on X-ray absorption techniques. In particular\, two progress will be discussed: (1) adopt the rational atom-binding strategy and develop the method of precise nano-confined synthesis\, subsequently establish the structure-property relationships in several functional nanomaterials anchored with single atoms by combining synchrotron XAS and XPS [2-5]; (2) propose the controllable ion-intercalating and ion-exchanging strategies and develop the method of in-situ reconstructed synthesis\, eventually clarify the working mechanism of cation-/anion-modulated functional nanomaterials by the means of operando XAS with synchrotron-on-line devices[6-9]. \n  \nReferences: \n\nhttp://en.nsrl.ustc.edu.cn/main.htm\n\nAtomically dispersed platinum supported on curved carbon supports for efficient electrocatalytic hydrogen evolution\, Nature Energy\, 2019\, 4:512-518. https://doi.org/10.1038/s41560-019-0402-6\n\nAchieving Efficient Alkaline Hydrogen Evolution Reaction over a Ni5P4 Catalyst Incorporating Single-Atomic Ru Sites\, Advanced Materials\, 2020\, 32:1906972. https://doi.org/10.1002/adma.201906972\n\nElectrochemical Conversion of CO2 to Syngas with Controllable CO/H2 Ratios over Co and Ni Single-Atom Catalysts\, Angewandte Chemie International Edition\, 2020\, 59:3033-3037. https://doi.org/10.1002/anie.201912719\n\nSingle Nickel Atoms on Nitrogen-Doped Graphene Enabling Enhanced Kinetics of Lithium-Sulfur Batteries\, Advanced Materials\, 2019\, 31:1903955. https://doi.org/10.1002/adma.201903955\n\nStable Metallic 1T-WS2 Nanoribbons Intercalated with Ammonia Ions: The Correlation between Structure and Electrical/Optical Properties\, Advanced Materials\, 2015\, 27:4837-4844. https://doi.org/10.1002/adma.201502134\n\nAtomic Cobalt Covalently Engineered Interlayers for Superior Lithium-Ion Storage\, Advanced Materials\, 2018\, 30:1802 https://doi.org/10.1002/adma.201802525525.\n\nTracking Structural Self-Reconstruction and Identifying True Active Sites toward Cobalt Oxychloride Precatalyst of Oxygen Evolution Reaction\, Advanced Materials\, 2019\, 31:1805127. https://doi.org/10.1002/adma.201805127\n\nAtomic Sn4+ Decorated into Vanadium Carbide MXene Interlayers for Superior Lithium Storage\, Advanced Energy Materials\, 2018\, 9:1802977. https://doi.org/10.1002/aenm.201802977 \n\n\n 
URL:https://xrayabsorption.org/events/journalclub-li-song/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200723
DTEND;VALUE=DATE:20200724
DTSTAMP:20260718T192052
CREATED:20200621T135236Z
LAST-MODIFIED:20200727T030438Z
UID:490-1595462400-1595548799@xrayabsorption.org
SUMMARY:Matthew Marcus: Soft x-ray spectromicroscopy in extraterrestrial materials
DESCRIPTION:Extraterrestrial materials such as meteorites and interplanetary dust particles are often very complex and non-uniform\, with diverse species within a small sample. In some cases\, especially for the products of sample-return missions\, the available samples are small and precious. X-ray micro- and nano-spectroscopy are ideal complements to other methods such as TEM and nano-SIMS. In this talk\, I will review several examples from the literature showing how X-ray spectromicroscopy has been used to study extraterrestrial materials and infer their histories of formation and alteration. I will also review some experimental techniques\, especially STXM. \nReferences: \n\nSandford\, Scott A.\, et al. “Organics captured from comet 81P/Wild 2 by the Stardust spacecraft.” Science 314\, no. 5806 (2006): 1720-1724.\nLo\, Yuan Hung\, et al. “Multimodal x-ray and electron microscopy of the Allende meteorite.” Science advances 5\, no. 9 (2019): eaax3009.\nVan Aken\, P. A.\, and B. Liebscher. “Quantification of ferrous/ferric ratios in minerals: new evaluation schemes of Fe L 23 electron energy-loss near-edge spectra.” Physics and Chemistry of Minerals 29\, no. 3 (2002): 188-200.
URL:https://xrayabsorption.org/events/journalclub-matthew-marcus/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200727
DTEND;VALUE=DATE:20200729
DTSTAMP:20260718T192052
CREATED:20200621T135456Z
LAST-MODIFIED:20200727T030303Z
UID:492-1595808000-1595980799@xrayabsorption.org
SUMMARY:Andy Aquila: The Tender X-ray Imaging (TXI) instrument at the LCLS
DESCRIPTION:This presentation will take place at 6 pm Monday\, Seattle (Los Angeles) time / 9 am Tuesday\, Beijing time using Zoom. For the Zoom link and password\, visit  https://tinyurl.com/XAFStalks  within 30 minutes of the beginning of the presentation. \nThe Linac Coherent Light Source (LCLS) upgrade to a high repetition source offers new avenues to pump/probe X-ray spectroscopies. Here I will briefly introduce the new capabilities of the LCLS focusing on the Tender X-ray Instrument (TXI). The TXI instrument is a dual-beam instrument\, fed by both the soft X-ray and hard X-ray undulators of LCLS; a feature currently unique among XFEL instruments. The tender x-ray instrument will enable x-ray pump/x-ray probe techniques especially in the emerging field of nonlinear x-ray science\, support tender X-ray spectroscopy measurements\, and provide a coherent scattering/ forward diffraction instrument for sub-micron samples. It is designed to accommodate a variety of additional techniques\, such as absorption and photoemission spectroscopy\, as well as an array of samples from fixed targets to gases\, aerosols\, and liquid jet targets. \n\nAbbamonte\, et al.\, New Science Opportunities Enables by LCLS-II X-ray Lasers https://portal.slac.stanford.edu/sites/lcls_public/Documents/LCLS-IIScienceOpportunities_final.pdf\nhttps://lcls.slac.stanford.edu/instruments/neh-1-2
URL:https://xrayabsorption.org/events/journalclub-andy-aquila/
CATEGORIES:XAFS Journal Club
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200730
DTEND;VALUE=DATE:20200731
DTSTAMP:20260718T192052
CREATED:20200621T135910Z
LAST-MODIFIED:20200805T221341Z
UID:494-1596067200-1596153599@xrayabsorption.org
SUMMARY:Thomas Penfold: Towards the Rapid Analysis of XANES for Complex Systems using Deep Neural Networks
DESCRIPTION:X-ray spectroscopy delivers strong impact across the physical and biological sciences by providing end users with highly detailed information about the electronic and geometric structure of matter. To decode this information in challenging cases\, e.g.\, in operando catalysts\, batteries\, and temporally evolving systems [1]\, advanced theoretical calculations are necessary. The complexity and resource requirements often render these out of reach for end users\, and therefore\, the data are often not interpreted exhaustively\, leaving a wealth of valuable information unexploited. In this talk\, I will discuss our recently developed method based upon supervised machine learning of X-ray absorption spectra through the development of a deep neural network (DNN) [2]. This DNN is able to estimate Fe K-edge X-ray absorption near-edge structure spectra in less than a second with no input beyond geometric information about the local environment of the absorption site. We predict peak positions with sub-eV accuracy and peak intensities with errors over an order of magnitude smaller than the spectral variations that the model is engineered to capture. I will also discuss its extension to other absorption edges\, the properties of the network and also highlights areas on which future developments should focus. \nReferences: \n\n C. J. Milne\, T. J. Penfold and M. Chergui Coord. Chem. Rev. 277\, 44-68 (2014).\nC. D. Rankine\, M. M. M. Madkhali\, and T. J. Penfold J. Phys. Chem. A 2020\, 124\, 21\, 4263?4270
URL:https://xrayabsorption.org/events/journalclub-thomas-penfold/
CATEGORIES:XAFS Journal Club
END:VEVENT
END:VCALENDAR