Browsing by Author "Fernandez-Alonso, F"

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    The instrument suite of the European Spallation Source
    (Elsevier B. V., 2020-01-10) Andersen, KH; Argyriou, DN; Jackson, AJ; Houston, J; Henry, PF; Deen, PP; Toft-Petersen, R; Beran, P; Strobl, M; Arnold, T; Wacklin-Knecht, H; Vivanco, R; Parker, SF; Gussen, A; Kanaki, K; Scionti, G; Olsen, MA; Arai, M; Schmakat, Ph; Lechner, RE; Niedermayer, Ch; Schneider, H; Zanetti, M; Petrillo, C; Moreira, FY; Stepanyan, S; Luna, P; Calzada, E; Stahn, J; Voigt, J; Dupont, T; Hanslik, R; Siemers, DJ; Udby, L; Chowdhury, MAH; Klauser, Ch; Rouijaa, M; Lehmann, E; Heynen, A; Bustinduy, I; Schwaab, A; Raspino, D; Scatigno, C; del Moral, OG; Kiehn, R; Aprigliano, G; Zanatta, M; Huerta, M; Bellissima, S; Lerche, M; Holm-Dahlin, S; Huerta, M; Christensen, NB; Lohstroh, W; Gorini, G; Fenske, J; Hansen, UB; Klauser, C; Rodrigues, S; Müller, M; Gorini, G; Bovo, C; Hall-Wilton, R; Fabrèges, X; Siemers, DJ; Khaplanov, A; Tsapatsaris, N; Taylor, J; Christensen, M; Schefer, J; Woracek, R; Tozzi, P; Müller, M; Carlsen, H; Olsen, MA; Orecchini, A; Di Fresco, L; Paciaroni, A; Bovo, C; Magán, M; Hauback, BC; Elmer, J; Heenan, RK; Piscitelli, F; Masi, F; Bakedano, G; Klimko, S; De Bonis, A; Fedrigo, A; Lukáš, P; Frielinghaus, H; Stahn, J; Schweika, W; Markó, M; Pfeiffer, D; Kirstein, O; Di Fresco, L; Schreyer, A; Orszulik, A; Nowak, G; Butterweck, S; Šaroun, J; Paciaroni, A; Kolevatov, R; Lehmann, EH; Filges, U; Schreyer, A; Koenen, M; Bustinduy, I; Magán, M; Feygenson, M; Cooper, JFK; Abad, E; Senesi, R; Longeville, S; Llamas-Jansa, I; Schulz, M; Birk, JO; Sharp, M; Galsworthy, P; Šaroun, J; Martínez, J; Hiess, A; Holm-Dahlin, S; Filges, U; Pullen, SA; Guyon Le Bouffy, J; Schefer, J; Lukáš, P; Udby, L; Kozielewski, T; Niedermayer, C; Sacchetti, F; Hartl, M; Jaksch, S; Salhi, Z; Brückel, T; Aguilar, J; Aguilar, J; Seifert, M; Bordallo, HN; Robillard, T; Villacorta, FJ; Herranz, I; del Rosso, L; Hauback, BC; Orecchini, A; Fabrèges, G; Fenske, J; Neuhaus, J; Schillinger, B; Abad, E; Kittelmann, T; Lefmann, K; Seifert, M; Neuhaus, J; Herranz, I; Kolevatov, R; Annighöfer, B; Oksanen, E; Morgano, M; Laszlo, G; Freeman, PG; Kennedy, SJ; Bertelsen, M; Bellissima, S; Alba-Simionesco, C; Markó, M; Mezei, F; Chowdhury, M; Halcrow, W; Jestin, J; Lieutenant, K; Babcock, E; Rønnow, HM; Engels, R; del Moral, OG; Vickery, A; Rouijaa, M; Lavie, P; Petersson Årsköld, S; Glavic, A; Désert, S; Mannix, D; Scatigno, C; Petry, W; Christensen, NB; Violini, N; Villacorta, FJ; Porcher, F; Glavic, A; Scionti, G; Zanetti, M; Fernandez-Alonso, F; Rønnow, HM; Mosconi, M; Olsson, M; Stepanyan, S; Petrillo, C; del Rosso, L; Harbott, P; Sacchetti, F; Bertelsen, M; Kämmerling, H; Andreani, C; Schulz, M; Colognesi, D; Luna, P; Loaiza, L; Turner, D; Martínez, JL; Tartaglione, A; Sordo, F; Llamas-Jansa, I; Schmakat, P; Lechner, RE; Poqué, A; Fernandez-Alonso, F; Colognesi, D; Tartaglione, A; Morgano, M; Webb, N; Loaiza, L; Whitelegg, L; Petry, W; Iversen, K; Vivanco, R; Tozzi, P; Goukassov, A; Schillinger, B; Carlsen, H; Masi, F; Christensen, M; Nowak, G; Nightingale, J; Schütz, S; Lopez, CI; Langridge, S; Schütz, S; Nagy, G; Zanatta, M; Andreani, C; Lefmann, K; Lohstroh, W; Mosconi, M; Senesi, R; Stefanescu, I; Bakedano, G; Hagen, ME; Wischnewski, A; Bourges, P; Hansen, UB; De Bonis, A; Kiehn, R; Parker, SF; Iversen, K; Sordo, F; Freeman, PG; Birk, JO; Rodríguez, DM; Ansell, S
    An overview is provided of the 15 neutron beam instruments making up the initial instrument suite of the European Spallation Source (ESS), and being made available to the neutron user community. The ESS neutron source consists of a high-power accelerator and target station, providing a unique long-pulse time structure of slow neutrons. The design considerations behind the time structure, moderator geometry and instrument layout are presented. The 15-instrument suite consists of two small-angle instruments, two reflectometers, an imaging beamline, two single-crystal diffractometers; one for macromolecular crystallography and one for magnetism, two powder diffractometers, and an engineering diffractometer, as well as an array of five inelastic instruments comprising two chopper spectrometers, an inverse-geometry single-crystal excitations spectrometer, an instrument for vibrational spectroscopy and a high-resolution backscattering spectrometer. The conceptual design, performance and scientific drivers of each of these instruments are described. All of the instruments are designed to provide breakthrough new scientific capability, not currently available at existing facilities, building on the inherent strengths of the ESS long-pulse neutron source of high flux, flexible resolution and large bandwidth. Each of them is predicted to provide world-leading performance at an accelerator power of 2 MW. This technical capability translates into a very broad range of scientific capabilities. The composition of the instrument suite has been chosen to maximise the breadth and depth of the scientific impact of the early years of the ESS, and provide a solid base for completion and further expansion of the facility. © 2020 The Authors. Published by Elsevier B.V. Open access article under the CC BY-NC-ND license.
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    Localized relaxational dynamics of succinonitrile
    (American Chemical Society, 2009-08-20) van Eijck, L; Best, AS; Long, S; Fernandez-Alonso, F; MacFarlane, D; Forsyth, M; Kearley, GJ
    Succinonitrile (N C-CH2-CH2-C N) is a good ionic conductor, when doped with an ionic compound, at room temperature, where it is in its plastic crystalline phase (Long et al. Solid State Ionics 2003, 161. 105: Alarco et al. Nat. Mater. 2004, 3, 476). We report on the relaxational dynamics of the plastic phase near the two first-order phase transitions and on the effect of dissolving a salt in the plastic matrix by quasi-elastic neutron scattering. At 240 K, the three observed relaxations are localized and we can describe their dynamics (iota approximate to 1.7, 17, and 140 ps) to a certain extent from a model using a single molecule that was proposed by Bee et al. allowing for all conformations in its unit cell (space group IM3M). The extent of the localized motion as observed is however larger than that predicted by the model and suggests that the isomerization of succinonitrile is correlated with a jump to the nearest neighbor site ill the unit cell. The salt containing system is known to be it good ionic conductor, and our results show that the effect of the ions on the succinonitrile matrix is homogeneous. Because the isomerizations and rotations are governed by intermolecular interactions, the dissolved ions have ail effect over ail extended range. Due to the addition of the salt, the dynamics of one of the components (iota approximate to 17 ps) shows more diffusive character at 300 K. The calculated upper limit of the corresponding diffusion constant of succinonitrile in the electrolyte is a factor 30 higher than what is reported for the ions. Our results suggest that the succinonitrile diffusion is caused by nearest neighbor jumps that are localized on the observed length and time scales. © 2009, American Chemical Society
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    P–V–T equation of state of synthetic mirabilite (Na2SO4·10D2O) determined by powder neutron diffraction
    (John Wiley & Sons, Inc, 2013-04) Fortes, AD; Brand, HEA; Vočadlo, L; Lindsay-Scott, A; Fernandez-Alonso, F; Wood, IG
    Neutron powder diffraction data have been collected from Na2SO4·10D2O (the deuterated analogue of mirabilite), a highly hydrated sulfate salt that is thought to be a candidate rock-forming mineral in some icy satellites of the outer solar system. These measurements, made using the OSIRIS instrument on the ISIS neutron spallation source, covered the range 0.1 < P < 545 MPa and 150 < T < 270 K. The refined unit-cell volumes as a function of pressure and temperature are parameterized in the form of a Birch–Murnaghan third-order equation of state, and the anisotropic linear incompressibilities are represented in terms of the elastic strain tensor. At 270 K, the bulk modulus K0,270 = 19.6 (1) GPa, its first pressure derivative ∂K/∂P = 5.8 (5) and its temperature dependence ∂K/∂T = −0.0175 (6) GPa K−1. The stiffest direction at 270 K, with a linear bulk modulus of ∼82 GPa, is coincident with the twofold axis of this monoclinic crystal. Of the remaining two principal directions, the most compressible (K ≃ 44 GPa) is roughly aligned with the c axis, and the intermediate value (K ≃ 59 GPa) is therefore approximately collinear with a*. With the aid of additional published data, a number of other important thermodynamic quantities have been derived, including the Grüneisen and Anderson–Grüneisen parameters, and the volume and enthalpy of melting along the high-pressure melting curve. Additional data obtained during this work, concerning the elastic properties of deuterated ice IV, are also presented. © 2013 International Union of Crystallography
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    Studies of finite molecular chains: synthesis, structural, magnetic and inelastic neutron scattering studies of hexa- and heptanuclear chromium horseshoes
    (Wiley, 2008-02-05) Ochsenbein, ST; Tuna, F; Rancan, M; Davies, RSG; Muryn, CA; Waldmann, O; Bircher, R; Sieber, A; Carver, G; Mutka, H; Fernandez-Alonso, F; Podlesnyak, A; Engelhardt, LP; Timco, GA; Gudel, HU; Winpenny, REP
    We report the synthesis and structural characterisation of a family of finite molecular chains, specifically [{[R2NH2](3) [Cr6F11 (O2CCMe3)(10)]}(2)] (in which R=nPr 1, Et 2, nBu 3), [{Et2NH}(2) {[Et2NH2](3)[Cr7F12(O2C-CMe3)(12)][HO2CCMe3](2)}(2)] (4), [{[Me2NH2](3)[Cr6F11(O2CCMe3)(10)]center dot 2.5 H2O}(4)] (5) and [I{iPr(2)NH(2)](3)[Cr7F12(O2CCMe3)(12)]}(2)] (6). The structures all contain horseshoes of chromium centres, with each Cr center dot center dot center dot Cr contact within the horseshoe bridged by a fluoride and two pivalates. The horseshoes are linked through hydrogen bonds to the secondary ammonium cations in the structure, leading to di- and tetrahorseshoe structures. Through magnetic measurements and inelastic neutron scattering studies we have determined the exchange coupling constants in 1 and 6. In 1 it is possible to distinguish two exchange interactions, J(A) = -1.1 meV and J(B) = -1.4 meV; J(A) is the exchange interactions at the tips of the horseshoe and JB is the exchange within the body of the horseshoe (1 meV = 8.066 cm(-1)). For 6 only one interaction was needed to model the data: J=-1.18meV The single-ion anisotropy parameters for Cr-III were also derived for the two compounds as: for 1, D-Cr = -0.028 meV and vertical bar ECr vertical bar = 0.005meV; for 6, D-Cr=-0.031meV. Magnetic-field-dependent inelastic neutron scattering experiments on I allowed the Zeeman splitting of the first two excited states and level crossings to be observed. For the tetramer of horseshoes (5), quantum Monte Carlo calculations were used to fit the magnetic susceptibility behaviour, giving two exchange interactions within the horseshoe (-1.32 and -1.65 meV) and a weak inter-horseshoe coupling of +0.12meV. Multi-frequency variable-temperature EPR studies on 1, 2 and 6 have also been performed, allowing further characterisation of the spin Hamiltonian parameters of these chains. © 1999-2020 John Wiley & Sons, Inc.