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  • 301.
    Kowalewski, Jozef
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Belorizky, Elie
    Fries, Pascal H
    Helm, Lothar
    Kruk, Danuta
    Sharp, Robert R
    Westlund, Per-Olof
    Comparison of different methods for calculating the paramagnetic relaxation enhancement of nuclear spins as a function of the magnetic field2008In: Journal of Chemical Physics, Vol. 128, p. 052315-Article in journal (Refereed)
    Abstract [en]

    The enhancement of the spin-lattice relaxation rate for nuclear spins in a ligand bound to a paramagnetic metal ion (known as the paramagnetic relaxation enhancement, PRE) arises primarily through the dipole-dipole (DD) interaction between the nuclear spins and the electron spins. In solution, the DD interaction is modulated mostly by reorientation of the nuclear spin-electron spin axis and by electron spin relaxation. Calculations of the PRE are in a general complicated, mainly because the electron spin interacts so strongly with the other degrees of freedom that its relaxation cannot be described by second-order perturbation theory, or the Redfield theory. Three approaches to resolve this problem exist in the literature: the so-called slow-motion theory, originating from Swedish groups, and two different methods based on simulations of the dynamics of electron spin in time domain, developed in Grenoble and Ann Arbor, respectively. In this paper, we report a numerical comparison of the three methods for a large variety of parameter sets, meant to correspond to large and small complexes of gadolinium(III) and of nickel(II). It is found that the agreement between the Swedish and the Grenoble approaches is very good for practically all parameter sets, while the predictions of the Ann Arbor model are similar in a number of the calculations but deviate significantly in others, reflecting in part differences in the treatment of electron spin relaxation. The origins of the discrepancies are discussed briefly.

  • 302.
    Kowalewski, Jozef
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bernatowicz, Piotr
    Carbon-13 NMR Relaxation Study of 1,8-Bis(dimethylamino)naphthalene in Isotropic Solution2008In: Journal of Physical Chemistry, Vol. 112, p. 4711-4714Article in journal (Refereed)
    Abstract [en]

    Nuclear spin relaxation in dimethylformamide-d7 solution of

    1,8-bis(dimethylamino)naphthalene (DMAN) was investigated. Detailed analysis

    of 13C longitudinal relaxation in this molecule yielded its rotational

    diffusion tensor. Comparison to protonated form of DMAN, DMANH+, leads to

    conclusions concerning interaction of the latter with its counterion.

  • 303.
    Kowalewski, Jozef
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Laaksonen, Aatto
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Aski, Sahar Nikkhou
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Westlund, Per-Olof
    Parigi, Giacomo
    Kruk, Danuta
    Egorov, Andrei
    Extensive NMRD studies of Ni(II) salt solutions in water and water-glycerol mixtures2008In: Journal of Magnetic Resonance, Vol. 195, p. 103-111Article in journal (Refereed)
    Abstract [en]

    Aqueous solutions of simple nickel(II) salts are a classical test case for theories of the paramagnetic relaxation enhancement (PRE) and its dependence on the magnetic field (nuclear magnetic relaxation dispersion, NMRD), going back to late fifties. We present here new experimental data, extending the NMRD range up to 21 Tesla (900 MHz). In addition to salt solutions in (acidified) water, we have also measured on solutions containing glycerol. The aqueous solution data do not show any significant changes compared to the earlier experiments. The interpretation, based on the general (“slow-motion”) theory is also similar to the earlier work from our laboratory. The NMRD data in mixed solvents are qualitatively different, indicating that the glycerol not only changes the solution viscosity, but may also enter the first coordination sphere of the metal ion, resulting in lower symmetry complexes, characterized by non-vanishing averaged zero-field splitting. This hypothesis is corroborated by molecular dynamics simulations. A strategy appropriate for interpreting the NMRD data for the chemically complicated systems of this type is proposed.

  • 304.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Carlson, S.
    High-pressure properties of TiP2O7, ZrP2O7 and ZrV2O72001In: Journal of Applied Crystallography, ISSN 0021-8898, Vol. 34, no 1, p. 7-12Article in journal (Refereed)
    Abstract [en]

    High-pressure synchrotron X-ray powder diffraction studies of TiP2O7, ZrP2O7 and ZrV2O7 have been performed. The ZrV2O7 structure undergoes a reversible transition at 1.38–1.58  GPa from cubic α- to pseudo-tetragonal β-ZrV2O7 that displays an orthorhombic 2 × 3 × 3 supercell. At pressures above 4  GPa, ZrV2O7 becomes irreversibly X-ray amorphous. No such transformations are observed for TiP2O7 and ZrP2O7, which compress smoothly up to the highest investigated pressures (40.3 and 20.5  GPa, respectively). These differences in high-pressure properties are discussed in terms of the negative thermal expansion of ZrV2O7. The bulk moduli at ambient pressure (B0) for TiP2O7, ZrP2O7, α-ZrV2O7 and β-ZrV2O7 were estimated to be 42  (3), 39  (1), 17.0  (7) and 20.8  (10)  GPa, respectively.

  • 305.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Carlson, S.
    High-Pressure Structures of α- and δ-ZrMo2O82001In: Acta Crystallographica Section B Structural science, ISSN 0108-7681, Vol. 57, no 1, p. 20-26Article in journal (Refereed)
    Abstract [en]

    In situ high-pressure synchrotron X-ray powder diffraction studies of trigonal α-ZrMo2O8, zirconium molybdate, have been performed from ambient conditions to 1.9  GPa, over the α–δ phase transition at 1.06–1.11  GPa. The monoclinic structure of δ-ZrMo2O8, stable between 1.1 and 2.5  GPa  at 298  K, has been solved by direct methods and refined using the Rietveld method. Significant distortions of the ZrO6 and MoO4 polyhedral elements are observed for δ-ZrMo2O8, as compared to the ambient conditions of the α-phase, while the packing of anions becomes more symmetric at high pressure.

  • 306.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Carlson, S.
    The high-pressure structures and properties of τ-Zr(HPO4)2Manuscript (Other academic)
  • 307.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Nielsen, R.B.
    Norby:, P.
    In-Situ Time-Resolved Synchrotron X-ray Powder Diffraction Studies of Hydrothermal Synthesis of Layered Titanium Phosphates.Manuscript (Other academic)
  • 308.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Norby:, P.
    Ab Initio Structure Determination and Rietveld Refinement of a High-Temperature Phase of Zirconium Hydrogen Phosphate and a New Polymorph of Zirconium Pyrophosphate from In-Situ Temperature-Resolved Powder Diffraction Data.2000In: Acta Crystallographica Section B, ISSN 0108-7681, Vol. 56, no 4, p. 618-625Article in journal (Refereed)
    Abstract [en]

    The collected in situ temperature-resolved synchrotron powder data revealed that the transformation of the recently reported three-dimensional τ-Zr(HPO4)2 to cubic ZrP2O7 goes through two intermediate phases. The first intermediate phase, ρ-Zr(HPO4)2, is formed in a reversible phase transition at 598  K, which involves both rearrangement and disordering of the hydrogen phosphate groups of τ-Zr(HPO4)2. At 688  K condensation of the hydrogen phosphate groups leads to the formation of the second intermediate, a new polymorph of zirconium pyrophosphate (β-ZrP2O7). Heating above 973  K results in the gradual transformation of β-ZrP2O7 to cubic zirconium pyrophosphate (α-ZrP2O7). The crystal structures of the two intermediate phases were solved from the in situ powder diffraction data using direct methods and refined using the Rietveld method. Both phases are orthorhombic, space group Pnnm and Z = 2. The lattice parameters for the two phases are: ρ-Zr(HPO4)2: a = 8.1935  (2), b = 7.7090  (2), c = 5.4080  (1)  Å; β-ZrP2O7: a = 8.3127  (5), b = 6.6389  (4), c = 5.3407  (3)  Å. The formation mechanism for the new zirconium pyrophosphate polymorph, β-ZrP2O7, is discussed in relation to structurally restricted soft chemistry

  • 309.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Norby, P.
    Structural Aspects of the Dehydration and Dehydroxylation of Layered γ-Titanium Phosphate, γ-Ti(PO4)(H2PO4)⋅2H2O.1998In: Inorganic chemistry, ISSN 1520-510X, Vol. 37, no 17, p. 4313-4320Article in journal (Refereed)
    Abstract [en]

    The thermal transformations of γ-titanium phosphate, γ-Ti(PO4)(H2PO4)·2H2O, have been studied using thermogravimetric analysis, differential scanning calorimetry, X-ray powder diffraction, and temperature-resolved in-situ powder diffraction. The transformation sequence goes from γ-Ti(PO4)(H2PO4)·2H2O over a new partially dehydrated form γ‘-Ti(PO4)(H2PO4)·(2−x)H2O (x 1) to the anhydrous form β-Ti(PO4)(H2PO4) and then through a two-step condensation process where layered titanium pyrophosphate, Ti(PO4)(H2P2O7)0.5, is formed first and finally cubic titanium pyrophosphate TiP2O7. The dehydration of γ-Ti(PO4)(H2PO4)·2H2O and the dehydroxylation/condensation process from β-Ti(PO4)(H2PO4) to layered titanium pyrophosphate,Ti(PO4)(H2P2O7)0.5, was followed in-situ. A new partially dehydrated phase, γ‘-Ti(PO4)(H2PO4)·(2−x)H2O (x 1), which forms at approximately 50 °C has been detected and characterized. The unit cell is monoclinic with the lattice parameters a = 23.670(1) Å, b = 6.264(1) Å, c = 5.036(1) Å, β = 102.41(1)°, and Z = 4. Layered titanium pyrophosphate, Ti(PO4)(H2P2O7)0.5, which forms at 375 °C has been characterized. The unit cell is monoclinic with lattice parameters a = 16.271(3) Å, b = 6.319(1) Å, c = 5.122(1) Å, β = 90.59(2)°, and Z = 4.

  • 310.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Norby, P.
    Hanson, J.C.
    Vogt, T.
    Preparation and Characterization of a New 3-Dimensional Zirconium Hydrogen Phosphate, τ-Zr(HPO4)2; Determination of the Complete Crystal Structure Combining Synchrotron X-ray Single Crystal Diffraction and Neutron Powder Diffraction.1998In: Inorganic chemistry, ISSN 1520-510X, Vol. 37, no 5, p. 876-881Article in journal (Refereed)
    Abstract [en]

    A new 3-dimensional zirconium hydrogen phosphate, τ-Zr(HPO4)2, was prepared by hydrothermal syntheses. The preparation, characterization, and determination of the crystal structure of this new material are reported. The structure was solved from single-crystal synchrotron diffraction on a 25 × 25 × 50 μm crystal. The position of the hydrogen atom was found using high-resolution neutron powder diffraction data. The unit cell is tetragonal, space group I41cd (No. 110), with lattice parameters a = 11.259(1) Å, c = 10.764(1) Å, and Z = 8. The structure can be described as a 3-dimensional framework built from ZrO6 octahedra bound together by hydrogen phosphate groups (PO3(OH)). The OH groups form a hydrogen-bonded spiral along the 41 axes, with each hydrogen phosphate both donating and accepting hydrogen bonds. The thermal transformations of τ-Zr(HPO4)2 were studied using in-situ temperature-resolved powder diffraction experiments. Hereby the existence of two new phases was discovered. The new phases have been indexed and the unit cell parameters are as follows. Intermediate I:  a = 8.172(1), b = 7.691(1), and c = 10.794(2) Å. Intermediate II: a = 8.283(2), b = 6.620(2), and c = 10.643(2) Å.

  • 311.
    Krogh Andersen, A.M.
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Norby, Poul
    Vogt, Tom
    Determination of the Formation Regions of Titanium Phosphates. Determination of the Crystal Structure of β-Titanium Phosphate, Ti(PO4)(H2PO4), from Neutron Powder Data.1998In: Journal of solid state chemistry, ISSN 1095-726X, Vol. 140, no 2, p. 266-271Article in journal (Refereed)
    Abstract [en]

    The formation region of the various types of layered titanium hydrogen phosphate hydrates was investigated. The materials were prepared by hydrothermal methods, treating amorphous titanium phosphate with phosphoric acid (8 to 16M) in the temperature range 175 to 250°C. The materials obtained were:α-Ti(HPO4)2·H2O,γ-Ti(PO4)(H2PO4)·2H2O, and its anhydrous formβ-Ti(PO4)(H2PO4). The structure ofβ-Ti(PO4)(H2PO4) has been determined by Rietveld powder refinement of high resolution neutron diffraction data. The structure is refined in the monoclinic space groupP21/n(No. 14). The unit cell parameters are:a=18.9503(4) Å,b=6.3127(1) Å,c=5.1391(1) Å,β=105.366(2)°;Z=4. The final agreement factors were:Rp=2.9% andRwp=3.8%. The structure ofβ-Ti(PO4)(H2PO4) is built from TiO6octahedra linked together by tertiary phosphate (PO4) and dihydrogen phosphate ((OH)2PO2) tetrahedra. The layers are held together by hydrogen bonds.

  • 312.
    Krogh Andersen, Anne
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Studies of Inorganic Layer and Framework Structures Using Time-, Temperature- and Pressure-Resolved Powder Diffraction Techniques2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is concerned with in-situ time-, temperature- and pressure-resolved synchrotron X-ray powder diffraction investigations of a variety of inorganic compounds with twodimensional layer structures and three-dimensional framework structures. In particular, phase stability, reaction kinetics, thermal expansion and compressibility at non-ambient conditions has been studied for 1) Phosphates with composition MIV(HPO4)2·nH2O (MIV = Ti, Zr); 2) Pyrophosphates and pyrovanadates with composition MIVX2O7 (MIV = Ti, Zr and X = P, V); 3) Molybdates with composition ZrMo2O8. The results are compiled in seven published papers and two manuscripts.

    Reaction kinetics for the hydrothermal synthesis of α-Ti(HPO4)2·H2O and intercalation of alkane diamines in α-Zr(HPO4)2·H2O was studied using time-resolved experiments. In the high-temperature transformation of γ-Ti(PO4)(H2PO4)·2H2O to TiP2O7 three intermediate phases, γ'-Ti(PO4)(H2PO4)·(2-x)H2O, β-Ti(PO4)(H2PO4) and Ti(PO4)(H2P2O7)0.5 were found to crystallise at 323, 373 and 748 K, respectively. A new tetragonal three-dimensional phosphate phase called τ-Zr(HPO4)2 was prepared, and subsequently its structure was determined and refined using the Rietveld method. In the high-temperature transformation from τ-Zr(HPO4)2 to cubic α-ZrP2O7 two new orthorhombic intermediate phases were found. The first intermediate phase, ρ-Zr(HPO4)2, forms at 598 K, and the second phase, β-ZrP2O7, at 688 K. Their respective structures were solved using direct methods and refined using the Rietveld method. In-situ high-pressure studies of τ-Zr(HPO4)2 revealed two new phases, tetragonal ν-Zr(HPO4)2 and orthorhombic ω-Zr(HPO4)2 that crystallise at 1.1 and 8.2 GPa. The structure of ν-Zr(HPO4)2 was solved and refined using the Rietveld method.

    The high-pressure properties of the pyrophosphates ZrP2O7 and TiP2O7, and the pyrovanadate ZrV2O7 were studied up to 40 GPa. Both pyrophosphates display smooth compression up to the highest pressures, while ZrV2O7 has a phase transformation at 1.38 GPa from cubic to pseudo-tetragonal β-ZrV2O7 and becomes X-ray amorphous at pressures above 4 GPa.

    In-situ high-pressure studies of trigonal α-ZrMo2O8 revealed the existence of two new phases, monoclinic δ-ZrMo2O8 and triclinic ε-ZrMo2O8 that crystallises at 1.1 and 2.5 GPa, respectively. The structure of δ-ZrMo2O8 was solved by direct methods and refined using the Rietveld method.

  • 313. Kruk, D
    et al.
    Kowalewski, Jozef
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    General treatment of paramagnetic relaxation enhancement associated with translational diffusion2009In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 130, p. -174104Article in journal (Refereed)
    Abstract [en]

    A theory of nuclear spin relaxation in isotropic liquids for nuclear spins interacting with electron spins, residing in other molecules (the outer-sphere relaxation), is presented. The approach, valid outside of the Redfield limit for electron spin relaxation, is an extension of the Swedish slow motion theory [ Benetis et al., Mol. Phys. 48, 329 (1983) ; Nilsson and Kowalewski, J. Magn. Reson. 146, 345 (2000) ] for inner-sphere relaxation. It is demonstrated that the outer-sphere relaxation rate can be expressed as an integral of a product of a translational diffusion correlation function and a function analogous to the inner-sphere spectral density. A numerical implementation of the theory is described and applied to a large number of realistic parameter sets for S = 7/2 and S = 1, which may correspond to Gd(III) and Ni(II) systems. It is shown that the outer-sphere contribution is relevant and should be included into the analysis of nuclear magnetic relaxation dispersion relaxation profiles, especially for slow relative translational diffusion and fast molecular tumbling

  • 314. Kyoi, D
    et al.
    Sato, T
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Rönnebro, E
    Kitamura, N
    Ueda, A
    Ito, M
    Katsuyama, S
    Hara, S
    Noréus, D
    Sakai, T
    A new ternary magnesium-titanium hydride Mg7TiHx with hydrogen desorption properties better than both binary magnesium and titanium hydride2004In: Journal of Alloys and Compunds, ISSN 0925-8388, Vol. 372, no 1-2, p. 213-217Article in journal (Refereed)
  • 315. Kyoi, D
    et al.
    Sato, T
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sakai, T
    Rönnebro, E
    Tsuji, Y
    Kitamura, N
    Ueda, A
    Ito, M
    Katsuyama, S
    Hara, S
    Noréus, D
    A novel magnesium–vanadium hydride synthesized by a gigapascal-high-pressure technique2004In: Journal of Alloys and Compounds, ISSN 0925-8388, Vol. 375, no 1-2, p. 253-258Article in journal (Refereed)
  • 316. Köver, Katalin
    et al.
    Gyula, Batta
    Kowalewski, Jozef
    Ghalebani, Leila
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Kruk, Danuta
    Internal dynamics of hydroxymethyl rotation from CH2 crosscorrelation in methyl-β-glucopyranoside2004In: Journal of Magnetic Resonance, ISSN 1090-7807, Vol. 167, no 2, p. 273-281Article in journal (Refereed)
  • 317.
    Laaksonen, A
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Self-assembled Materials: Encyclopedia of Complexity and System Science2008Book (Refereed)
  • 318. Laarz, Eric
    et al.
    Carlsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Vivien, Benoit
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Nygren, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bergström, Lennart
    Colloidal processing of Al2O3-based composites reinforced with TiN and TiC particulates, whiskers and nanoparticles2001In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 21, no 8, p. 1027-1035Article in journal (Refereed)
    Abstract [en]

    A colloidal processing route has been developed for the preparation of dense and homogeneous Al2O3–TiN/TiC composites. The dispersion and rheological properties of mixtures of TiN or TiC particulates and Al2O3 particles were investigated using electrokinetics and steady-shear rheology. We found that well-dispersed aqueous suspensions with low viscosity could be prepared by adding a poly(acrylic acid) dispersant and controlling pH in the alkaline range. This processing scheme was also suitable for preparation of whisker and nanoparticle composite suspensions. The alumina-based composite suspensions with a secondary-phase concentration of 25 vol.% were freeze-granulated and hot-pressed, and the resulting bodies were fully densified with well-dispersed secondary phases. Homogeneous Al2O3–TiN nanoparticle composites could only be prepared with additions of up to 5 vol.% nanoparticles; higher additions resulted in agglomeration and subsequent grain growth of the nanoparticles. 

  • 319.
    Landersjö, Clas
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stevensson, Baltzar
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Eklund, Robert
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Östervall, Jennie
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Maliniak, Arnold
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Söderman, Peter
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Molecular conformations of a disaccharide investigated using NMR spectroscopy2006In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 35, p. 89-101Article in journal (Refereed)
    Abstract [en]

    The molecular structure of -l-Rhap-(1→ 2)--l-Rhap-OMe has been investigated using conformation sensitive NMR parameters: cross-relaxation rates, scalar 3 J CH couplings and residual dipolar couplings obtained in a dilute liquid crystalline phase. The order matrices of the two sugar residues are different, which indicates that the molecule cannot exist in a single conformation. The conformational distribution function, , related to the two glycosidic linkage torsion angles and was constructed using the APME method, valid in the low orientational order limit. The APME approach is based on the additive potential (AP) and maximum entropy (ME) models. The analyses of the trajectories generated in molecular dynamics and Langevin dynamics (LD) computer simulations gave support to the distribution functions constructed from the experimental NMR parameters. It is shown that at least two conformational regions are populated on the Ramachandran map and that these regions exhibit very different molecular order. Electronic Supplementary Material  Supplementary material is available for this article at http://www.dx.doi.org/10.1007/s10858-006-9006-0 and is accessible for authorized users.

  • 320. Lang, Jan
    et al.
    Tosner, Zdenek
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Lhotak, Pavel
    Kowalewski, Jozef
    Reorientational Dynamics of Two Isomers of Thiacalix[4]arene2003In: Magnetic Resonance in Chemistry, ISSN 0749-1581, Vol. 41, no 10, p. 819-827Article in journal (Refereed)
  • 321. Law, Christopher J.
    et al.
    Almqvist, Jonas
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bernstein, Adam
    Goetz, Regina M.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Huang, Yafei
    Soudant, Celine
    Laaksonen, Aatto
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Wang, Da-Neng
    Salt-bridge dynamics control substrate-induced conformational change in the membrane transporter GlpT2008In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 378, no 4, p. 828-839Article in journal (Refereed)
    Abstract [en]

    Active transport of substrates across cytoplasmic membranes is of great physiological, medical and pharmaceutical importance. The glycerol-3-phosphate (G3P) transporter (GlpT) of the E. coli inner membrane is a secondary active antiporter from the ubiquitous major facilitator superfamily that couples the import of G3P to the efflux of inorganic phosphate (Pi) down its concentration gradient. Integrating information from a novel combination of structural, molecular dynamics simulations and biochemical studies, we identify the residues involved directly in binding of substrate to the inward-facing conformation of GlpT, thus defining the structural basis for the substrate-specificity of this transporter. The substrate binding mechanism involves protonation of a histidine residue at the binding site. Furthermore, our data suggest that the formation and breaking of inter- and intradomain salt bridges control the conformational change of the transporter that accompanies substrate translocation across the membrane. The mechanism we propose may be a paradigm for organophosphate:phosphate antiporters.

  • 322. Lee, Myeong H.
    et al.
    Björling, T.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Hauback, B. C.
    Utsumi, T.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Moser, D.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Bull, D.
    Noreus, Dag
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Structural Chemistry.
    Sankey, Otto F.
    Haeussermann, Ulrich
    Crystal structure, electronic structure, and vibrational properties of MAlSiH (M=Ca,Sr,Ba): Hydrogenation-induced semiconductors from the AlB2-type alloys MAlSi2008In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 78, no 19, p. 195209-Article in journal (Refereed)
    Abstract [en]

    Superconducting AlB2-type silicides CaAlSi, SrAlSi, and BaAlSi (MAlSi) absorb hydrogen and form semiconducting monohydrides where hydrogen is exclusively attached to Al. This induces a metal-nonmetal transition which is accompanied with only a minor rearrangement of the metal atoms. We report the synthesis and structure determination of CaAlSiH and BaAlSiH as well as a first-principles study of the electronic structure and vibrational property changes associated with the metal-nonmetal transition. We find that incorporation of H in MAlSi removes the partly occupied antibonding pi(*) band responsible for metallic behavior and turns it into an energetically low-lying Al-H bonding band. The fully occupied bonding pi band in MAlSi changes to a weakly dispersed band with Si p(z) (lone-pair) character in the hydrides, which becomes located below the Fermi level. The soft phonon mode in MAlSi pivotal for the superconducting properties stiffens considerably in the hydride. This mode is associated with the out-of-plane Al-Si vibration and is most affected by the formation of the Al-H bond. The mode of the Al-Si in-plane vibration, however, is unaffected, indicating that the Al-Si bond is equally strong in the metallic precursor and the semiconducting hydride. Al-H modes for MAlSiH are weakly dispersed. The frequencies of the stretching mode are around 1200 cm(-1) and virtually invariant to the M environment, indicating a covalent but weak Al-H interaction, which is interpreted as a dative bond from hydridic hydrogen to Al [Al <- H1-].

  • 323. Lee, Myeong H
    et al.
    Sankey, Otto F
    Bjoerling, Thomas
    Moser, David
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Noréus, Dag
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Parker, Stewart F
    Haeussermann, Ulrich
    Vibrational Properties of Polyanionic Hydrides SrAl2H2 and SrAlSiH: New Insights into Al-H Bonding Interactions2007In: Inorganic Chemistry, ISSN 0020-1669. CAN 147:333295 AN 2007:775930, Vol. 46, no 17, p. 6987-6991.Article in journal (Refereed)
  • 324. Lemmens, Peter
    et al.
    Hugonin, Zuzana
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Lidin, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Wulferding, Dirk
    Reinhard, K. Kremer
    Anomalous low temperature behaviour of the Co dimers in the oxo-halide CoSb2O3Br22008In: Journal of Solid State Chemistry, no 181, p. 2776-2782Article in journal (Refereed)
  • 325.
    Leonova, Ekaterina
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Structural Investigations of Complex Glasses by Solid-state NMR2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This PhD thesis presents structural investigations of amorphous inorganic materials: oxide and oxynitride glasses and mesoporous bioactive glasses (MBGs), by solid-state Nuclear Magnetic Resonance (NMR).

    Lanthanum oxide and oxynitride [La-Si-(Al)-O-(N)] glasses have a large number of potential applications due to their physical properties. In our work we have studied, compared to previous investigations, significantly expanded ranges of glass compositions (for oxynitride glasses, including samples of very high nitrogen content, up to 53 % out of the anions). We have estimated local environments of 29Si and 27Al structural units (their coordination, polymerization degree and number of N incorporated into tetrahedral units) in the materials. We have suggested a random Al/Si distribution along with almost uniform non-bridging oxygen atoms distribution in aluminosilicate glasses.

    Silicon nitride was used as precursor in the oxynitride glass synthesis. We studied both α- and β-modifications of silicon nitride, 15N-enriched, as well as fully (29Si, 15N)-enriched samples. We have shown that the linewidths of 15N NMR spectra are dominated by J(29Si-15N) coupling in 29Si315N4 sample.

    Mesoporous bioactive glasses in the CaO-SiO2-P2O5 system show superior bioactivity (the ability to form a hydroxycarbonate apatite layer on the glass surface when exposed to body fluids) compared to conventional bioactive glasses due to their large surface area and uniform pore-size distribution. Previous studies suggested a homogeneous cation distribution over the MBG samples on a 10−20 nm length-scale. From our results, on the other hand, we may conclude that Si and P is not intimately mixed. We propose a structural model, in which the pore walls of MBGs are composed of a silica network, and a phosphate phase is present as nanometer-sized clusters that are dispersed on the pore wall.

  • 326.
    Leonova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Edén, Mattias
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Vallet Regi, Maria
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Lopez Noriega, Adolfo
    Arcos, Daniel
    Izquierdo Barba, Isabel
    Multinuclear Solid-State NMR Studies of Ordered Mesoporous Bioactive Glasses2008In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 112, no 14, p. 5552-5562Article in journal (Refereed)
    Abstract [en]

    The local structures of highly ordered mesoporous bioactive CaO-SiO2-P2O5 glasses were investigated for variable Ca contents. 1H NMR revealed a diversity of hydrogen-bonded and "isolated" surface silanols as well as adsorbed water molecules. The structural roles of Si and P were explored using a combination of 29Si and 31P magic-angle spinning (MAS) nuclear magnetic resonance (NMR) techniques; the proximities of Si and P to protons were studied through cross-polarization-based experiments, including 1H-29Si and 1H-31P hetero-nuclear two-dimensional correlation spectroscopy. The results are consistent with SiO2 being the main pore-wall component, whereas P is present as a separate amorphous calcium orthophosphate phase, which is dispersed over the pore wall as nanometer-sized clusters. The excess Ca that is not consumed in the phosphate phase modifies the silica glass network where it associates at/near the mesoporous surface. This biphasic structural model of the pore wall leads to the high accessibility of both Ca and P to body fluids, and its relation to the experimentally demonstrated high in vitro bioactivities of these materials is discussed.

  • 327.
    Leonova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Grins, Jekabs
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Shariatgorji, Mohammadreza
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Eden, Mattias
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Solid-state NMR investigations of Si-29 and N-15 enriched silicon nitride2009In: Solid State Nuclear Magnetic Resonance, ISSN 0926-2040, E-ISSN 1527-3326, Vol. 36, no 1, p. 11-18Article in journal (Refereed)
  • 328.
    Leonova, Ekaterina
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hakeem, Abbas S.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Stevensson, Baltzar
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Grins, Jekabs
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Esmaeilzadeh, Saeid
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Edén, Mattias
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Nitrogenrich La-Si-Al-O-N oxynitride glass structures probed by solid state NMR2008In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 354, no 1, p. 49-60Article in journal (Refereed)
    Abstract [en]

    We investigate the local structures of oxynitride La–Si–(Al)–O–N glasses by 29Si and 27Al magic-angle spinning (MAS) solid state Nuclear Magnetic Resonance (NMR). The glasses studied span an unprecedented range of compositions, up to >50 at.% lanthanum and nitrogen out of the cations and anions, respectively, and achievable through a recently introduced glass preparation route. Transmission as well as scanning electron microscopy verified homogeneous samples over length-scales down to 20 nm. As the nitrogen content of the glasses increased, 29Si NMR evidenced a progressive formation of Si–N bonds, with SiO2N2 tetrahedra dominating in the nitrogen-rich glass networks. In the oxygen-rich end of the series, aluminum is predominantly present in tetrahedral coordination as AlO4, whereas the glasses with highest nitrogen contents have a major fraction of AlO3N structural units. Trends in isotropic 29Si and 27Al chemical shifts and 27Al quadrupolar couplings are compared with results of La–Si–Al–O glasses and are discussed in relation to the glass compositions and their proposed structures.

  • 329. Li, M R
    et al.
    Kuo, K H
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sun, J L
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hovmöller, S
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Crystal structure of the 2/1 cubic approximant Ag42In42Yb162008In: Journal of Alloys and Compounds, Vol. 465, p. 132-138Article in journal (Refereed)
  • 330. Li, M
    et al.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Kuo, K
    "A new hexagonal phase displaying pseudo-icosahedral symmetry in Zn–Mg–Y alloy”2009In: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 60, no 8, p. 683-686Article in journal (Refereed)
    Abstract [en]

    A number of hexagonal phases displaying pseudo-icosahedral symmetry have been reported in Zn–Mg–RE alloy, but no cubic or orthorhombic approximants. In the present work another new hexagonal phase, H0 (a = 9.1A ˚ , c = 19.7A ˚ ), was found to coexist with H-(Zn,Mg)5Y. Their orientation relationship was determined to be h100iH0 || h100iH, [001]H0 || [001]H. Since their electron diffraction patterns are similar to the corresponding patterns of an icosahedral quasicrystal, they are both considered to be approximants of the Zn–Mg–Y icosahedral quasicrystal.

     

  • 331. Li, Ming
    et al.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Nygren, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Origin(s) of the apparent high permittivity in CaCu3Ti4O12 ceramics: Clarification on the contributions from internal barrier layer capacitor and sample-electrode contact effects2009In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 106, no 10, p. 104106/1-104106/8Article in journal (Refereed)
    Abstract [en]

    CaCu3Ti4O12 ceramics with a range of resistivities have been prepared using both conventional sintering and spark plasma sintering. For all cases, the high effective permittivity is associated primarily with an internal barrier layer capacitor mechanism. Additional polarization associated with the electrode-sample interface may appear but its visibility depends on the grain boundary resistivity (Rgb) of the ceramic. If the Rgb is large, the electrode polarization is obscured by sample-related effects; if the Rgb is small, a separate impedance associated with the electrode polarization may be seen. Discrepancies in the literature regarding the magnitude and origin of the high effective permittivity are attributed to a combination of differences in processing conditions, electrode contact material and measuring frequency range

  • 332.
    Li, Shuai
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bergman, B
    Zhao, Zhe
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    "Synthesis of La0.9Sr0.1Al0.85Mg0.1Co0.05O2.875 using a polymeric method"2009In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 20, no 6, p. 1133-1128Article in journal (Refereed)
    Abstract [en]

    Nanocrystalline La0.9Sr0.1Al0.85Mg0.1Co0.05O2.875 (LSAMC) powders were synthesized via a polymeric method using poly(vinyl alcohol) (PVA). The effect of PVA content on the synthesized powders was studied. When the ratio of positively charged valences (Mn+) to hydroxyl groups (-OH) is 1.5:1, crystalline LaAlO3 could be obtained at such a low calcination temperature as 700 degrees C. While at 900 degrees C the ratio is of less importance, since pure LaAlO3 perovskite could be formed for all powders after calcination at 900 degrees C. Thermal analysis (TG/DTA) was utilized to characterize the thermal decomposition behaviour of precursor powders. The chemical structure of the calcined powder was studied by Fourier transform infrared (FTIR) spectroscopy. The powder morphology and microstructure were examined by SEM. Dense pellets with well-developed submicron microstructures could be formed after sintering at 1450 degrees C for 5 h. Compared with the solid-state reaction method, the sintering temperature is substantially lower for powder prepared by the PVA method. This is due to the ultrafine and highly reactive powder produced. Keywords: Nanocrystalline; Lanthanum aluminate; Perovskite; Polymeric method

  • 333. Lia, M. R.
    et al.
    Hovmöller, Sven
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Kuo, K. H
    Crystal structure of the 2/1 cubic approximant Ag42In42Yb162007In: Journal of Alloys and CompoundsArticle in journal (Refereed)
  • 334.
    Lidin, Sven
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Christensen, J
    Jansson, Kjell
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Fredrickson, D
    Incommensurate Stistaite-Order Made to Order2009In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 48, no 12, p. 5497-5503Article in journal (Refereed)
    Abstract [en]

    The stistaite SbSn phase contg. 40-57 at.% Sb was investigated by using single crystal x-ray diffraction and EDX to yield a simple relation between the modulated structure and compn.  Stistaite is incommensurately ordered over its entire stability region.

  • 335.
    Lidin, Sven
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Johnsson, Mats
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Hugonin, Zuzana
    Modulations in the Onoratoite system2009In: Solid State Sciences, ISSN 1293-2558, E-ISSN 1873-3085, Vol. 11, p. 1198-1205Article in journal (Refereed)
    Abstract [en]

    The iodide form of the mineral onoratoite was synthesized, and like the Cl and Br based analogs, it displays super structure ordering, but for the iodide, the super structure is clearly incommensurate.  Due to the poor quality of crystals attainable, the structure was solved by converting the soln. of the Cl analog to a super space formalism, and then using the structural elements from this soln. to model the iodide. The structure is triclinic, crystg. in the 3+1d super space group P-1

  • 336.
    Lidin, Sven
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Piao, Shu-Ying
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    The Structure of Cu6Sn5-xSb(x) - Large Effects of Subtle Doping2009In: Zeitschrift für Anorganische und Allgemeines Chemie, ISSN 0044-2313, E-ISSN 1521-3749, Vol. 635, no 4-5, p. 611-613Article in journal (Refereed)
    Abstract [en]

     

     

     

     

     

     

      

     

     

     

     

     

     

     

     

      

    Small amounts of antimony shifts the thermal stability range of ht-Cu

    6Sn. To make this phase stable at room temperature, and easily accessible by prolonged annealing, a model previously suggested for the ht-phase is shown to be entirely correct in this single crystal study.

  • 337. Lidin, Sven
    et al.
    Piao, ShuYing
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Boström, M.
    The incommensurately modulated structure of Ho13Zn58: a little order goes a long wayIn: Solid State Sci.Article in journal (Refereed)
  • 338. Lin, Yuan-Hua
    et al.
    Ce-Wen, Nan
    Liu, Yuheng
    Li, Jingfeng
    Mizokawa, T.
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    High-temperature electrical transport and thermoelectric power of partially substituted Ca3Co4O9-based ceramics2007In: Journal of the American Ceramic Society, Vol. 90, no 1, p. 132-136Article in journal (Refereed)
  • 339. Lin, Yuan-Hua
    et al.
    Lan, Jinle
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    High-temperature electrical transport behaviors in textured Ca3Co4O9-based polycrystalline ceramics2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, no 7, p. 072107/1-072107/3Article in journal (Refereed)
    Abstract [en]

    Highly (00l) oriented Ca3Co4O9-based ceramics were fabricated by spark plasma sintering combined with a dynamic forging process. The grain orientation is effective in lowering the electrical resistivity and enhancing the thermoelectric power factor but with little influence on the Seebeck coefficient. A metallic-to-semiconducting transition temperature can be observed and the activation energy is almost independent of the La-doping. All of the Ca3Co4O9-based ceramic samples exhibit large thermoelectric power, and the figure of merit for La-doped Ca3Co4O9 sample can reach 0.26 at 975 K, which can be a promising candidate of p-type material for high-temperature thermoelectric application

  • 340. Lin, Yuan-Hua
    et al.
    Liu, Yong
    Zhang, Bo-Ping
    Nan, Ce-Wen
    Li, Jing-Feng
    Shen, Zhijian
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry, Inorganic Chemistry.
    Electrical transport properties of La2CuO4 ceramics processed by the spark plasma sintering2007In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 90, no 12, p. 4005-4008Article in journal (Refereed)
    Abstract [en]

    Highly dense La2CuO4 ceramics have been prepared by the spark plasma sintering technique. Temperature dependence of electrical conductivity indicates that La2CuO4 ceramics sintered at over 875 degrees C exhibit a metal-like behavior, which should be ascribed to the special La2CuO4 crystal structure and its correlation splitting of the half-filled d(x2-y2) band. Our experimental data indicate that all of the La2CuO4 samples exhibit positive thermoelectric power in the whole measuring temperature range, indicating that the majority of charge carriers are holes. It is desirable to obtain good thermoelectric performance for this system by optimizing the electrical properties and reducing the thermal conductivity.

  • 341.
    Lind, Hanna
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Modulations in Intermetallic Families of Compounds2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is based on a study of five distinct intermetallic systems with the aim of expanding the general knowledge of aperiodically modulated crystal structures. Families of compounds that contain a variety of superstructures together with incommensurately modulated structures have been investigated mainly by means of single crystal X-ray diffraction and higher dimensional structure models.

    A uniform (3+1)-dimensional structure for Bi-Se phases was developed with the composition as a single variable. The structure description is based on a cubic NaCl type structure with homoatomic layer stackings. It is shown by computational modelling that the formation energies of bismuth selenides with more than 40 at. % Bi are close to zero, a result that supports the idea of a continuous series of stackings corresponding to an ordered solid solution of Bi in Bi2Se3.

    The Nowotny chimney-ladder structures are described with a (3+1)-dimensional composite structure, valid for all such compounds regardless of the included elements, the composition or the valence electron concentration. A new member is added to this family by the ZrBi1.62 compound. The modulation is believed to arise as a secondary effect of the criteria of a fixed electron count.

    A symmetry analysis is presented for the RE1+ε(MB)4 (RE = rare earth elements, M = iron metal elements) family of compounds and a uniform (3+1)-dimensional composite structure description has been developed. The modulation may be due to the presence of unusually short contacts between the RE channel atoms, giving rise to a rotational modulation of the (MB)4 tetraederstern chains.

    A (3+1)-dimensional incommensurate structure has been determined for the novel δ1 – CoZn compound. The structure displays a unique assembly of fused icosahedra and the modulation is induced by geometric strain.

    The structure of the K(PtSi)4 compound was re-determined. Despite a close kinship with the RE1+ε(MB)4 compounds, this structure is not modulated.

  • 342.
    Lind, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Boström, Magnus
    Re-determining the Nowotny chimney-ladder structure VGe1.82 from powder diffraction dataIn: Powder DiffractionArticle in journal (Refereed)
  • 343.
    Lind, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Boström, Magnus
    Petricek, Vaclav
    Lidin, Sven
    Structure of δ1-CoZn7.8 transformation?: an example of a phason pinning-unpinning transformation?2003In: Acta Crystallografica B, ISSN 0108-7681, Vol. 59, p. 720-729Article in journal (Refereed)
  • 344.
    Lind, Hanna
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Lidin, Sven
    A general model for Bi-Se phases using a superspace formalism2003In: Solid State Sciences, ISSN 1293-2558, Vol. 5, no 1, p. 47-57Article in journal (Refereed)
  • 345.
    Lindberg, Fredrik
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Studies of Oxygen Deficient Complex Cobaltates with Perovskite Related Structures2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The present thesis deals with the investigation of some perovskite related complex cobaltates. The phases Sr2Co2-xGaxO5 (0.3 ≤ x ≤ 0.7), Sr2Co2-xAlxO5 (0.3 ≤ x ≤ 0.5), Sr1-xBixCoO3-y (0.1 ≤ x ≤ 0.2), Sr0.75Y0.25Co1-xGaxO2.625 (0.125 ≤ x ≤ 0.375) and Sr0.75Y0.25Co1-xFexO2.625+δ (0.125 ≤ x ≤ 0.625) were synthesised and characterised. All these compounds crystallises with similar structures, they are all composed by altering layers of octahedra and tetrahedra although in the two former, the tetrahedra are organised in chains (the Brownmillerite structure), while in the latter three the tetrahedra arranges as segregated Co4O12 units (the 314 type structure). The techniques X-ray and neutron diffraction, transmission electron microscopy, thermal analysis and magnetic measurements were used to track structural and important physical properties.

  • 346.
    Lindberg, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Drozhzhin, Oleg A.
    Istomin, Sergey Ya.
    Svensson, Gunnar
    Kaynak, F. Betül
    Svedlindh, Peter
    Warnicke, Peter
    Wannberg, Anders
    Mellergård, Anders
    Antipov, Eugene V.
    Synthesis and characterization of Sr0.75Y0.25Co1−xMxO2.625+δ (M=Ga, 0.125≤ x≤ 0.500 and M=Fe, 0.125≤ x≤ 0.875)2006In: Journal of Solid State Chemistry, ISSN 0022-4596, Vol. 179, no 5, p. 1434-1444Article in journal (Refereed)
  • 347.
    Lindberg, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Istomin, Sergey Ya.
    Berastegui, Pedro
    Svensson, Gunnar
    Kazakov, Sergey M.
    Antipov, Eugene V.
    Synthesis and structural studies of Sr2Co2-xGaxO5, 0.3 ≤ x ≤ 0.82003In: Journal of Solid State Chemistry, ISSN 0022-4596, Vol. 173, no 2, p. 395-406Article in journal (Refereed)
  • 348.
    Lindberg, Fredrik
    et al.
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Svensson, Gunnar
    Istomin, Sergey Ya.
    Aleshinskaya, Sergey V.
    Antipov, Eugene V.
    Synthesis and structural studies of Sr2Co2-xAlxO5, 0.3 ≤ x ≤ 0.52004In: Journal of Solid State Chemistry, ISSN 0022-4596, Vol. 177, no 4-5, p. 1592-1597Article in journal (Refereed)
  • 349. Lindgren, Matteus
    et al.
    Laaksonen, Aatto
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Westlund, Per-Olof
    A theoretical spin relaxation and molecular dynamics simulation study of the Gd(H2O)(9)(3+) complex2009In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 11, no 44, p. 10368-10376Article in journal (Refereed)
    Abstract [en]

    A theoretical analysis of the paramagnetically enhanced water proton spin-lattice relaxation of a hydrated Gd3+ ion is combined with  Molecular Dynamics (MD) simulations. The electron-proton dipole-dipole  correlation function, C-p(DD)(tau), as well as the pseudo-rotation ( PR) model of the transient zero-field splitting (ZFS) are evaluated  with the help of the data from MD simulations. The fast local water  motion in the first hydration shell, i.e. the wagging and rocking motions, is found not to change the mono exponential character of the dipole correlation function C-p(DD)(tau), but is important in the time dependence of the transient ZFS interaction. The dynamics of the transient ZFS interaction is modeled as the water-induced electric field gradient tensor at the site of the metal ion. This approach follows the ideas of the pseudo-rotation model, describing the fluctuating zero-field interaction as a constant amplitude in the principal frame but reorienting according to a rotational diffusion equation of motion. The MD results indicate that the pseudo-rotation model gives a multi-exponential correlation function which oscillates at short times and is described by three exponential terms. The time scale is shorter than previously assumed but contain an intermediate time constant (1-2 ps). The electron spin resonance (ESR) spectral width at half height at frequencies of X- band,Q-band, 75 MHz, 150 MHz and 225 MHz can be reproduced at 320 K  without any contributions from 4th or 6th rank ZFS interactions. Consequently,there are two mutually inconsistent dynamic models of the  ZFS interaction which can describe the water proton T-1-NMRD (nuclear  magnetic resonance dispersion) profile and the field dependent ESR spectra of the hydrated Gd(III) complex equally well.

  • 350. Lipowski, P
    et al.
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Aldinger, F
    Ahniyaz, A
    Hoffmann, R C
    Bill, J
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Controlling the assembly of nanocrystalline ZnO films by a transient amorphous phase in solution2008In: Journal of Physical Chemistry C, Vol. 112, p. 5373-5383Article in journal (Refereed)
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