Search Results - (Author, Cooperation:W. F. Kuhs)
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1Latest Papers from Table of Contents or Articles in PressStaff View
Publication Date: 2014-12-17Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsPublished by: -
2Articles: DFG German National LicensesLondono, J. D. ; Kuhs, W. F. ; Finney, J. L.
College Park, Md. : American Institute of Physics (AIP)
Published 1993Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Detailed structural studies using powder neutron diffraction have been carried out on ices III and IX on both under-pressure and recovered samples. The incomplete hydrogen ordering in recovered ice IX first observed by La Placa et al. is confirmed, and our studies suggest similar orderings for the under-pressure and recovered phases. Sample history was observed to influence the lattice constants of ice IX, an effect which could relate to hydrogen ordering. There is an indication that ice III is not fully disordered, a conclusion which would be consistent with independent thermodynamic measurements.Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesFujara, F. ; Wefing, S. ; Kuhs, W. F.
College Park, Md. : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Using deuteron NMR, spin alignment tetrahedral jumps of 2H in deuterated polycrystalline hexagonal ice (Ih) have been observed. Both geometry and time scale of the process are determined directly. At T=230 K the correlation time of these jumps is 0.21(3) ms. The tetrahedral hydrogen jumps turn out to scatter—most characteristically for the disorder within the hydrogen subsystem—randomly about the tetrahedral angles by about ±3° with a correlation time of 0.5(1) ms. With additional experiments on specifically doped ices it is shown that these tetrahedral jumps are due to diffusing Bjerrum vacancies.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Measurements were done at the four-circle neutron diffractometer D9 of the Institut Laue-Langevin using a wavelength of 0.7107(5) A on a pure specimen of 6.5 mm3 cut from a larger sample (supplied by A. Chaillou, Laboratoire de Glaciologie, Grenoble). The temperature was maintained using a closed ...Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Ice has eleven known crystalline phases (Fig. 1), in which the watermolecules are linked through hydrogen bonds into tetrahedralframeworks. Thisuncommonly large number of different solid phases attests to thestructural versatility of the water molecule. Here we reportthe identification ...Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesStaff View
ISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Gas hydrates of the noble gases were first described by Villard2 (argon) and de Forcrand3'4 (krypton and xenon). Most of the gas hydrates crystallize in one of two distinct clathrate structures: type I provides cages for molecules up to 5.8 A in diameter while type II accepts molecules with a ...Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesBurggraf, M. ; Dragan, H. ; Gruner-Bauer, P. ; Helberg, H. W. ; Kuhs, W. F. ; Mattern, G. ; Müller, D. ; Wendl, W. ; Wolter, A. ; Dormann, E.
Springer
Published 1995Staff ViewISSN: 1434-6036Keywords: 75.20 ; 72.90 ; 61.65 ; 76.30.PSource: Springer Online Journal Archives 1860-2000Topics: PhysicsNotes: Abstract Crystal structure, microwave conductivity and static magnetic susceptibility were analyzed for the conducting perylene (PE) radical cation salts of nominal composition (PE)2(PF6)1−x (AsF6) x ·2/3 THF for 0≦x≦1. Crystallographic phase transitions in the high-temperature metal phase were also characterized by differential scanning calorimetry and electron spin resonance. The Peierls transition occuring at 100–120 K (depending onx) and the opening of the energy gap in the semiconductor phase were determined from the magnetic data. The dependence of these properties on the size of the complex anions and the packing of the PE molecules is discussed.Type of Medium: Electronic ResourceURL: