ALBERT

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nilsson, A -- Wernet, Ph -- Nordlund, D -- Bergmann, U -- Cavalleri, M -- Odelius, M -- Ogasawara, H -- Naslund, L-A -- Hirsch, T K -- Ojamae, L -- Glatzel, P -- Pettersson, L G M -- New York, N.Y. -- Science. 2005 May 6;308(5723):793; author reply 793.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Stanford Synchrotron Radiation Laboratory, P.O. Box 20450, Stanford, CA 94309, USA. nilsson@slac.stanford.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15879194" target="_blank"〉PubMed〈/a〉

Description: X-ray absorption spectroscopy and x-ray Raman scattering were used to probe the molecular arrangement in the first coordination shell of liquid water. The local structure is characterized by comparison with bulk and surface of ordinary hexagonal ice Ih and with calculated spectra. Most molecules in liquid water are in two hydrogen-bonded configurations with one strong donor and one strong acceptor hydrogen bond in contrast to the four hydrogen-bonded tetrahedral structure in ice. Upon heating from 25 degrees C to 90 degrees C, 5 to 10% of the molecules change from tetrahedral environments to two hydrogen-bonded configurations. Our findings are consistent with neutron and x-ray diffraction data, and combining the results sets a strong limit for possible local structure distributions in liquid water. Serious discrepancies with structures based on current molecular dynamics simulations are observed.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wernet, Ph -- Nordlund, D -- Bergmann, U -- Cavalleri, M -- Odelius, M -- Ogasawara, H -- Naslund, L A -- Hirsch, T K -- Ojamae, L -- Glatzel, P -- Pettersson, L G M -- Nilsson, A -- RR-08630/RR/NCRR NIH HHS/ -- New York, N.Y. -- Science. 2004 May 14;304(5673):995-9. Epub 2004 Apr 1.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Stanford Synchrotron Radiation Laboratory, Post Office Box 20450, Stanford, CA 94309, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15060287" target="_blank"〉PubMed〈/a〉

Description: Water has a number of anomalous physical properties, and some of these become drastically enhanced on supercooling below the freezing point. Particular interest has focused on thermodynamic response functions that can be described using a normal component and an anomalous component that seems to diverge at about 228 kelvin (refs 1-3). This has prompted debate about conflicting theories that aim to explain many of the anomalous thermodynamic properties of water. One popular theory attributes the divergence to a phase transition between two forms of liquid water occurring in the 'no man's land' that lies below the homogeneous ice nucleation temperature (TH) at approximately 232 kelvin and above about 160 kelvin, and where rapid ice crystallization has prevented any measurements of the bulk liquid phase. In fact, the reliable determination of the structure of liquid water typically requires temperatures above about 250 kelvin. Water crystallization has been inhibited by using nanoconfinement, nanodroplets and association with biomolecules to give liquid samples at temperatures below TH, but such measurements rely on nanoscopic volumes of water where the interaction with the confining surfaces makes the relevance to bulk water unclear. Here we demonstrate that femtosecond X-ray laser pulses can be used to probe the structure of liquid water in micrometre-sized droplets that have been evaporatively cooled below TH. We find experimental evidence for the existence of metastable bulk liquid water down to temperatures of 227(-1)(+2) kelvin in the previously largely unexplored no man's land. We observe a continuous and accelerating increase in structural ordering on supercooling to approximately 229 kelvin, where the number of droplets containing ice crystals increases rapidly. But a few droplets remain liquid for about a millisecond even at this temperature. The hope now is that these observations and our detailed structural data will help identify those theories that best describe and explain the behaviour of water.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sellberg, J A -- Huang, C -- McQueen, T A -- Loh, N D -- Laksmono, H -- Schlesinger, D -- Sierra, R G -- Nordlund, D -- Hampton, C Y -- Starodub, D -- DePonte, D P -- Beye, M -- Chen, C -- Martin, A V -- Barty, A -- Wikfeldt, K T -- Weiss, T M -- Caronna, C -- Feldkamp, J -- Skinner, L B -- Seibert, M M -- Messerschmidt, M -- Williams, G J -- Boutet, S -- Pettersson, L G M -- Bogan, M J -- Nilsson, A -- England -- Nature. 2014 Jun 19;510(7505):381-4. doi: 10.1038/nature13266.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉1] SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA [2] Department of Physics, AlbaNova University Center, Stockholm University, S-106 91 Stockholm, Sweden. ; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, PO Box 20450, Stanford, California 94309, USA. ; 1] SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA [2] Department of Chemistry, Stanford University, Stanford, California 94305, USA. ; PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA. ; Department of Physics, AlbaNova University Center, Stockholm University, S-106 91 Stockholm, Sweden. ; 1] Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany [2] Linac Coherent Light Source, SLAC National Accelerator Laboratory, PO Box 20450, Stanford, California 94309, USA. ; 1] SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA [2] Institute for Methods and Instrumentation in Synchrotron Radiation Research, Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH, Wilhelm-Conrad-Rontgen Campus, Albert-Einstein-Strasse 15, 12489 Berlin, Germany. ; Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany. ; Linac Coherent Light Source, SLAC National Accelerator Laboratory, PO Box 20450, Stanford, California 94309, USA. ; Mineral Physics Institute, Stony Brook University, Stony Brook, New York, New York 11794-2100, USA. ; 1] SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA [2] Department of Physics, AlbaNova University Center, Stockholm University, S-106 91 Stockholm, Sweden [3] Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, PO Box 20450, Stanford, California 94309, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24943953" target="_blank"〉PubMed〈/a〉

Description: Cellulose is the major polysaccharide of plants where it plays a predominantly structural role. A variety of highly specialized microorganisms have evolved to produce enzymes that either synergistically or in complexes can carry out the complete hydrolysis of cellulose. The structure of the major cellobiohydrolase, CBHI, of the potent cellulolytic fungus Trichoderma reesei has been determined and refined to 1.8 angstrom resolution. The molecule contains a 40 angstrom long active site tunnel that may account for many of the previously poorly understood macroscopic properties of the enzyme and its interaction with solid cellulose. The active site residues were identified by solving the structure of the enzyme complexed with an oligosaccharide, o-iodobenzyl-1-thio-beta-cellobioside. The three-dimensional structure is very similar to a family of bacterial beta-glucanases with the main-chain topology of the plant legume lectins.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Divne, C -- Stahlberg, J -- Reinikainen, T -- Ruohonen, L -- Pettersson, G -- Knowles, J K -- Teeri, T T -- Jones, T A -- New York, N.Y. -- Science. 1994 Jul 22;265(5171):524-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Molecular Biology, Uppsala University, Sweden.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8036495" target="_blank"〉PubMed〈/a〉

Description: We used the Linac Coherent Light Source free-electron x-ray laser to probe the electronic structure of CO molecules as their chemisorption state on Ru(0001) changes upon exciting the substrate by using a femtosecond optical laser pulse. We observed electronic structure changes that are consistent with a weakening of the CO interaction with the substrate but without notable desorption. A large fraction of the molecules (30%) was trapped in a transient precursor state that would precede desorption. We calculated the free energy of the molecule as a function of the desorption reaction coordinate using density functional theory, including van der Waals interactions. Two distinct adsorption wells-chemisorbed and precursor state separated by an entropy barrier-explain the anomalously high prefactors often observed in desorption of molecules from metals.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dell'Angela, M -- Anniyev, T -- Beye, M -- Coffee, R -- Fohlisch, A -- Gladh, J -- Katayama, T -- Kaya, S -- Krupin, O -- LaRue, J -- Mogelhoj, A -- Nordlund, D -- Norskov, J K -- Oberg, H -- Ogasawara, H -- Ostrom, H -- Pettersson, L G M -- Schlotter, W F -- Sellberg, J A -- Sorgenfrei, F -- Turner, J J -- Wolf, M -- Wurth, W -- Nilsson, A -- New York, N.Y. -- Science. 2013 Mar 15;339(6125):1302-5. doi: 10.1126/science.1231711.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Hamburg and Center for Free Electron Laser Science, Hamburg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23493709" target="_blank"〉PubMed〈/a〉

Description: Femtosecond x-ray laser pulses are used to probe the carbon monoxide (CO) oxidation reaction on ruthenium (Ru) initiated by an optical laser pulse. On a time scale of a few hundred femtoseconds, the optical laser pulse excites motions of CO and oxygen (O) on the surface, allowing the reactants to collide, and, with a transient close to a picosecond (ps), new electronic states appear in the O K-edge x-ray absorption spectrum. Density functional theory calculations indicate that these result from changes in the adsorption site and bond formation between CO and O with a distribution of OC-O bond lengths close to the transition state (TS). After 1 ps, 10% of the CO populate the TS region, which is consistent with predictions based on a quantum oscillator model.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ostrom, H -- Oberg, H -- Xin, H -- LaRue, J -- Beye, M -- Dell'Angela, M -- Gladh, J -- Ng, M L -- Sellberg, J A -- Kaya, S -- Mercurio, G -- Nordlund, D -- Hantschmann, M -- Hieke, F -- Kuhn, D -- Schlotter, W F -- Dakovski, G L -- Turner, J J -- Minitti, M P -- Mitra, A -- Moeller, S P -- Fohlisch, A -- Wolf, M -- Wurth, W -- Persson, M -- Norskov, J K -- Abild-Pedersen, F -- Ogasawara, H -- Pettersson, L G M -- Nilsson, A -- New York, N.Y. -- Science. 2015 Feb 27;347(6225):978-82. doi: 10.1126/science.1261747. Epub 2015 Feb 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics, AlbaNova University Center, Stockholm University, SE-10691, Sweden. ; SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 95305, USA. ; SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany. ; Physics Department and Center for Free Electron Laser Science, University of Hamburg, Luruper Chausse 149, D-22761 Hamburg, Germany. ; Department of Physics, AlbaNova University Center, Stockholm University, SE-10691, Sweden. SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany. ; Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. ; Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany. Fakultat fur Physik und Astronomie, Universitat Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany. ; Fritz-Haber Institute of the Max-Planck-Society, Faradayweg 4-6, D-14195 Berlin, Germany. ; Physics Department and Center for Free Electron Laser Science, University of Hamburg, Luruper Chausse 149, D-22761 Hamburg, Germany. Deutsches Elektronen-Synchrotron, Photon Science, Notkestrasse 85, D-22607 Hamburg, Germany. ; Surface Science Research Centre and Department of Chemistry, The University of Liverpool, Liverpool, L69 3BX, UK. ; Department of Physics, AlbaNova University Center, Stockholm University, SE-10691, Sweden. SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA. nilsson@slac.stanford.edu.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25722407" target="_blank"〉PubMed〈/a〉