bluuebunny/crossref_metadata_2025 huggingface dataset:
35Cl NQR, Crystal Structure, and Pyroelectricity of 2,3-Dichloro-1,4-naphthoquinone
Authors: Brummer Stefanie , Sohling Ulrich , Weiss Alarich
Published: February 2015

The 35Cl NQR spectra of the two phases (phases I and II) of 2,3-dichloro-1,4-naphthoquinone were studied from 77 to 394 K. The crystal structure determination of the triclinic phase (phase I) was refined by single crystal X-ray diffraction. Phase I crystallizes in the space group C1
i-P1̄. The unit cell (Z = 4) has the dimensions a = 1614.3(4) pm, 6 = 828.1 (3) pm, c = 733.2(3) pm, α = 67.02(1)°, β = 82.55(1)°, γ = 89.77(1)°. In the temperature range 439≦ TI→II/K≦447 a unidirectional phase transition I → II is observed. Phase II is orthorhombic, space group C5
2v-Pb21a. The bond distances d(C-CI) and the 35Cl NQR frequencies correlate quite well according to the theory: v(35Cl) ~ (d(C-CI)) 3- The multiplicity of the 35Cl NQR spectra is discussed. Pyroelectricity studies on phase II are reported. The pyroelectric coefficient depends little on the temperature, 8.3≦px/μCm-2 K-1≦10.7 in 103 ≦T/K≦343.
NQR Investigations of La3-x Ba3+xCu6O3 , (x = 0, 0.75, 1)
Authors: Okuda T. , Ueki T. , Yamada K. , Ichiba S. , Atobea K. , Yoshida H.
Published: February 2015

NQR spectra due to 63Cu and 139La have been recorded for La3-xBa3+xCu6O (x = 0, 0.75, 1). Two groups of 63Cu NQR lines were observed (around 20-23 MHz and 29-36 MHz). The former is assigned to the Cu atoms in the CuO4 square planar groups, and the latter to that in the CuO s square pyramidal group. For the 63Cu NQR lines in La3Ba3Cu6O , the time dependent NQR spectra and the temperature dependence of NQR frequencies were observed.
Molecular Motions in (CH3)3XCl, X = Sn and Pb. NMR Investigations and Crystal Structure Study of (CH3)3PbCl and CH3SnBr3
Authors: Zhang Da , Dou Shi-Qi , Weiss Alarich
Published: February 2015

The molecular motion in (CH3)3XCl, X = Sn and Pb has been investigated by measurement of the second moment M2(1H) as function of temperature in the range 95 < T,/K<345. The methyl groups in both compounds rotate freely over the whole temperature range studied. In (CH3)3SnCl the C'3-rotation of (CH3)3Sn-group about the Sn CI axis sets in above 273 K. To explain the NMR and INS results, the crystal structures of (CH3)3PbCl and CH3SnBr3 were determined by single X-ray diffraction. (CH3)3PbCl crystallizes in a monoclinic space group C3
2-C2, a = 1276.7(3) pm, b = 982.3(3) pm, c = 547.0(2) pm, ß = 91.12(1)°; Z = 4, R = 0.035. CH3SnBr3 crystallizes in an orthorhombic space group D16
2h-Pnma, a = 643.0(3) pm, b= 1005.3(4) pm, c= 1148.0(4) pm; Z = 4, R =0.057
Low-Frequency Electromagnetic Properties of an Alternating Stack of Thin Uniaxial Dielectric Laminae and Uniaxial Magnetic Laminae
Authors: Patrick S. Reese , Lakhtakia Akhlesh
Published: February 2015

Analysis is carried out for an alternating arrangement of laminae which have either uniaxial permittivity or uniaxial permeability dyadics. The unit cell is constructed of two laminae such that the ones with the uniaxial permittivity dyadic alternate with the ones with the uniaxial permeability dyadic through the stack. It is assumed that both dyadics have the same optic axis. The 4-vector method is utilized to construct a characteristic matrix for the two-lamina unit cell. After assuming that each lamina is electrically thin, the properties of an equivalent medium are obtained: both the permeability and the permittivity dyadics of the equivalent medium are biaxial
A Comparative Study of the BJH- and MCYL-Type Potentials Applied to the Gaseous Water Dimer
Authors: Slanina Zdenek
Published: February 2015

Various refined potentials describing the intra- and inter-molecular force fields of water molecules arc used to calculate the properties of the gas-phase water dimer. The intra-molecular parts have been taken from spectroscopic or quantum-chemical sources. The minimum energy structure was found iteratively using the first derivatives of the potential; the force-constant matrix was constructed by numerical difierentation. A quite close agreement between the Bopp-Jancso-Heinzinger and the Matsuoka-Clementi-Yoshimine-Lie potentials is found. The treatment is applied to seven observed water-dimer isotopomeric isomerizations
Molecular Dynamics Study of Microscopic Mechanism of Diffusion in Li2SiO3 System
Authors: Habasaki Junko
Published: February 2015

MD simulation has been performed to learn the microscopic mechanism of diffusion of ions in the Li2SiO3 system.

The motion of lithium ions can be explained by the trapping model, where lithium is trapped in the polyhedron and moves with fluctuation of the coordination number. The mean square displacement of lithium was found to correlate well with the net changes in coordination number.
On the Entropy of the Hard Sphere Fluid
Authors: Baranyai Andräs , Evans Denis J.
Published: February 2015

The expansion of the entropy into one-body, two-body, three-body, etc. contributions was applied to estimate the excess entropy of the hard sphere fluid. Configuration samples provided by computer simulation were used to determine the two-particle and three-particle correlation functions. The results show that even at intermediate densities a non-negligible part of the structural information is represented by four-body and higher order correlations.
Calculation of Lower Bounds to Energy Eigenvalues of He, Li+ and Li by Means of the Effective Field Method
Authors: Fleischhauer Jörg , Schleker Wolfgang , Raabe Gerhard
Published: February 2015

Two versions of the effective field method have been applied to calculate lower bounds to the energy eigenvalues of the small systems He, Li+, and Li. Although our modified method leads to an improvement compared with the originally proposed scheme, the results are still far from being satisfying.
NQR Study of the Pinning and Depinning of the Incommensurate Modulation Wave in the Presence of Impurities
Authors: Milia F. , Papavassiliou G. , Anagnostopoulos A.
Published: February 2015

High temperature-resolution NQR measurements in an ultra pure Rb2ZnCl4 crystal and a mixed [Rb1-x(NH4)x]2ZnCl4 crystal with a controlled amount of impurities (x = 0.01) verify the existence of a temperature region where the characteristic incommensurate line splitting is averaged out. The results show that for the system with high purity the averaging of the incommensurate splitting is due to large thermal fluctuations. In contrast, for the mixed crystal the added impurities seem to play the predominant role.
The Intensity Patterns with a Multi-Crystal Diffractometer Observed at a Synchrotron Source
Authors: Gartstein E. L. , Cowley R. A.
Published: February 2015

The intensity is calculated employing the expressions developed for a multi-crystal diffractometer. Comparison with the measurements shows the reliability of the formalism and enables better interpretation of the experimental results.
7Li-MR Studies on Molecular Motion of Hydrated Lithium Ions in Concentrated Aqueous Solutions of LiCl, LiBr, and LiSCN at Low Temperatures
Authors: Hasebe Tooru , Tanaka Kazuko
Published: February 2015

Nuclear spin-lattice relaxation times, T1, of 7Li in 13.8mol/kg LiCl-H2O and 12.3 mol/kg LiCl-D2O solutions have been measured in the temperature range 80K-313K. They showed similar temperature dependences with the same minimum values (27 ± 1 ms) which proved that the electric quadrupole interaction is dominant for the relaxation of 7Li-NMR. The T1 and T2 values of 7Li-NMR in concentrated aqueous solutions of LiCl (8-14 mol/kg), LiBr (8-10 mol/kg) and LiSCN (8-14 mol/kg) at 80 K to 300 K have been studied to obtain information concerning the dynamic properties of Li+ ions and the effect of anions. T1 at temperatures higher than the glass transition point is governed by a tumbling motion of the hydrated lithium ions.
Thermodynamics and Structure of Isothiocyanate Complexes of Manganese(II), Cobalt(II) and Zinc(II) Ions in N,N-Dimethylacetamide
Authors: Koide Makoto , Ishiguro Shin-ichi
Published: February 2015

The complexation of manganese (II), cobalt (II) and zinc(II) with thiocyanate ions has been studied in N,N-dimethylacetamide (DMA) by calorimetry and spectrophotometry at 298 K. In these metal systems the formation of a series of four isothiocyanato complexes, [M(NCS)n](2-n)+ (n = 1÷4; M = Mn, Co, and Zn) was established, and their formation constants, enthalpies and entropies were determined. Interestingly, the complexation behavior in DMA is significantly different from that in N,N-dimethylformamide (DMF), despite of the similarity of the physicochemical properties of these solvents. The complexation is indeed enhanced significantly in DMA over DMF and is more exothermic in the former solvent. Furthermore, with cobalt(II) an octahedral to tetrahedral coordination geometry change was found to occur in DMA at an earlier step of complexation than in DMF. These results suggest that six-coordination of DMA molecules to a metal ion is severely sterically hindered.
Structure of the Solvated Strontium and Barium Ions in Aqueous, Dimethyl Sulfoxide and Pyridine Solution, and Crystal Structure of Strontium and Barium Hydroxide Octahydrate
Authors: Persson Ingmar , Sandström Magnus , Yokoyama Haruhiko
Published: February 2015

Single crystal X-ray data, collected at 298 K, are used to redetermine the crystal structure of the non-isomorphic compounds [Sr(H2O)8](OH)2 and [Ba(H2O)8](OH)2. The eight water oxygen atoms form distorted Archimedean antiprisms around the octahydrated metal ions with mean metal ion-oxygen distances 2.62 and 2.79 Å for strontium and barium, respectively. A second coordination shell of 24 hydrogen-bonded oxygen atoms with mean metal ion-oxygen distances M…OII 4.76 and 4.80 Å, respectively, is observed. The hydroxide ions in both structures have an unusual hydrogen bond arrangement with 5 bonds accepted and one donated.

The structure of the solvated strontium and barium ions in aqueous, dimethyl sulfoxide and pyridine solutions has been studied by means of large angle X-ray scattering and extended X-ray absorption fine structure spectroscopy techniques. In aqueous solution independent determinations of the first-sphere metal-oxygen coordination by the two techniques resulted in the bond lengths Sr-O 2.63 (2) and Ba-O 2.81 (3) Å, and for both metal ions a hydration number of 8.1 (3). The second coordination spheres are very diffuse with only about 13 water molecules at similar M…OII distances as in the crystal structures and 2-3 water molecules closer to the metal ions. In dimethyl sulfoxide solution both ions were found to coordinate 6.0 (5) solvent molecules with the distances Sr-O 2.54(1), Sr…S 3.77(1) Å, and Ba-O 2.76(1), Ba…S 3.99(1) Å. For the solvated ions in pyridine solution EXAFS measurements yielded the distances Sr-N 2.57 (2) and Ba-N 2.78 (3) Å, with a probable solvation number of 6.

Correlations of hydration enthalpies and partial molar volumes with experimental M-O bond distances in aqueous solution are used to discuss hydration numbers and bond character for all of the alkaline earth metal ions.
Comparison of the Structure of Liquid Amides as Determined by Diffraction Experiments and Molecular Dynamics Simulations
Authors: Schoester Pia C. , Zeidler Manfred D. , Radnai Tamäs , Bopp Philippe A.
Published: February 2015

The intermodular structures of liquid formamide, N-methylformamide and N,N-dimethylformamide at room temperature are studied by means of NVE molecular dynamics computer simulations. Newly developed flexible models are used. X-ray and neutron weighted structure and total radial pair distribution functions are computed from the simulated site-site pair distribution functions. They are compared with experimental results. The agreement is usually satisfactory as far as heavy atom pairs are concerned while the lengths of the hydrogen bonds are found to be systematically too long in the simulations.
Solid-Solute Phase Equilibria in Aqueous Solutions IX. Thermodynamic Analysis of Solubility Measurements: La(OH)m(CO3)q•rH2O
Authors: Gamsjäger Heinz , Marhold Harald , Königsberger Erich , Tsai Yi Jung , Kolmer Hans
Published: February 2015

The aqueous solubilities of La(OH)0.8(CO3)1.1.0.1 H2O, basic lanthanum carbonate of ancylite type, have been investigated as a function of ionic strength at 25.0 °C. The stoichiometric solubility constants defined by log* KI
ps0 = log [La3 +] + 1.1 log pCO2 - 3 log [H+] have the values 11.10, 11.32, 11.42, 11.63, and 11.70 for I = 0.1, 0.25, 1.0, 2.0, and 4.0 mol kg -1(Na)ClO4 respectively. The extrapolation to infinite dilution using the Pitzer equations resulted in a "thermodynamic" solubility constant, log* K°pz0 = 10.48 ± 0.08. This in turn led to the Gibbs energy of ancylite formation: Δf G⊖
298 {La(OH)0.8(CO3)1.1 · 0.1 H2O} = - 1.531.5 kJ mol-1.
Dielectric Relaxation of NaClO4Solutions in Formamide, N-Methylformamide, and N,N-Dimethylformamide
Authors: Barthel J. , Bachhuber K. , Büchner R.
Published: February 2015

Complex permittivity spectra in the frequency range 0.95 ≤ v/[GHz] ≤ 89 for N,N-dimethylformamide (DMF), N-methylformamide (NMF), formamide (FA) and their solutions of NaClO4 are investigated to study the change of liquid structure and dynamics arising from the availability of one hydrogen-bond acceptor site together with no (DMF), one (NMF), or two (FA) donor sites on the same molecule. Three solvent relaxation processes are observed for NMF and two for FA and DMF. The relaxation parameters are used to determine solvation numbers. They show that ion-solvent interactions lead to a reduction of the average length of the H-bonded NMF chains but have only moderate influence on the FA structure. An additional solute relaxation process in DMF solutions is due to the diffusion-controlled formation and decomposition of solvent-shared ion pairs.
Ist 91Zr-Festkörper-Kernresonanzspektroskopie praktikabel?
Authors: Hartmann P. , Scheler G.
Published: February 2015

91Zr solid state NMR spectra have been observed for samples possessing different zirconium local-site environments (e.g. phosphates, fluorides). Depending on the quadrupole coupling, different NMR experiments have been utilized. In case of weak quadrupole coupling, magic angle spinning (MAS) is suitable. Otherwise, spin echo techniques are necessary to overcome “acoustic ringing’’ and receiver dead-time limitations. Using the step echo method, the detection of the very broad 91Zr signals is not limited by non-uniform spectral excitation. The obtained 91Zr chemical shifts range from -246 ppm to 208 ppm, the quadrupole coupling frequencies from 50 kHz to 2.7 MHz..
Creation and Recombination of Frenkel Defects in AgBr
Authors: Funke K. , Lauxtermann T. , Wilmer D. , Bennington S. M.
Published: February 2015

Complete ionic conductivity spectra as well as quasielastic and inelastic neutron scattering spectra have been taken of solid silver bromide at various temperatures. High-amplitude vibrational move­ments, essentially of the silver ions, contribute to both kinds of spectra. In particular, a conductivity maximum, located at about 500 GHz, reflects oscillations of individual silver ions along directions. -The microwave and millimetre-wave conductivities are dominated by a thermally activated Debye-type relaxation process. The effect is consistently explained by the frequent hopping of silver ions from regular octahedral lattice sites into tetrahedral interstitial sites and back again, i.e., by the frequent creation and recombination of Frenkel pairs. -The effect is also responsible for the existence of thermally activated quasielastic components in the neutron scattering spectra. The width of the coherent quasielastic scattering shows that the forward-backward hopping of a silver ion is accompanied by fast correlated movements of ions in its immediate neighbourhood.
Rational Interpolation Formulae for the Excess Functions of Binary Mixtures
Authors: Brodowsky H.
Published: February 2015

A variation of the commonly used polynomial interpolation formulae for the excess functions of binary mixtures is proposed, in which the cross-calculation of the coefficients of partial and integral molar functions is greatly facilitated.
Some Aspects of Spinodal Decomposition in Spinel Solid Solutions
Authors: Burkert N. , Grüne R. , Schmalzried H. , Rahman S.
Published: February 2015

Decomposition morphologies of supersaturated spinel solid solutions in the quasi-binary system Co2TiO4-CoAl2O4 at 973 K show all pertinent features of spinodal decomposition. Since the decomposition morphology may not be considered as sufficient evidence for a spinodal process, the thermodynamics of the spinel solid solutions and the linear transport theory of spinodal decomposition were combined to corroborate the experimental results of the early decomposition reaction.

Simultaneous ordering, a common property of ternary and higher nonequilibrium solid solutions, was also observed. These ordering processes occur locally in distinct regions of the spinel crystal. Moreover, the spinodal wavelength λ increases in time according to λ ∞ t, which is unusual and will be discussed in the light of cation diffusion in semiconducting oxides with two cation sublattices.
SIMS Investigations on the SmCo5Dnand LaNi5HnSystems
Authors: Dobrileit R. , Züchner H.
Published: February 2015

Characteristic secondary ion emission patterns of several metal-hydrogen systems have been measured by SIMS to get information about the metal-hydrogen bonding and the structure of these systems. Results on SmCo5Dn and LaNi5Hn, and on H-D-loaded samples of the pure components are presented. The emission patterns of the secondary ions show a stronger bonding of hydrogen to Co and Ni than to Sm and La, although these transition metals, contrary to Sm or La, do not form stable hydrides under normal conditions. In these AB5-compounds the transition metal seems to be transformed to a "hydride forming material" due to the presence of the rare earth element. The secondary ion emission patterns of the hydrogen loaded intermetallics are explained and compared to those of the hydrogen loaded pure components.

The similarity in the secondary ion emission patterns of the SmCo5Dn and LaNi5Hn systems points to a general characteristic of AB5Hn materials.
Proton Diffusion in Strontium Cerate Ceramics studied by Quasielastic Neutron Scattering and Impedance Spectroscopy
Authors: Karmonik Ch. , Hempelmann R. , Matzke Th. , Springer T.
Published: February 2015

Perovskite structured strontium cerate doped with ytterbium and water, e.g. SrCe0.95Yb0.05 H0.02O2.985, is a well known proton conductor at elevated temperatures. We have studied its proton conductivity or diffusivity, respectively, by impedance spectroscopy, IS, and by quasielastic neutron scattering, QENS. While the former method yields a macroscopic proton diffusion coefficient, the latter method allows to elucidate the microscopic proton diffusion mechanism. It consists of a sequence of free diffusion and trapping/escape events with the Yb3+ ions acting as trapping centers. The self-diffusion coefficient obtained with QENS agrees with the conductivity diffusion coefficient obtained with IS.
Decomposition of Plane Waves into Irreducible Representations of Space Groups
Authors: Teuscher H. , Kramer P.
Published: February 2015

Using a relation between representation theory of crystallographic space groups and a Dirichlet type of boundary problem for the Laplacian, we derive the solutions for the Dirichlet problem, as well as for a similar Neumann boundary problem, by a complete decomposition of plane waves into irreducible representations of a particular space group. This decomposition corresponds to a basis transformation in L2(Ω) and yields a new set of basis functions adapted to the symmetry of the lattice considered.
Molecular Motion in Solid Tetraethyl -and Tetrapropylammonium Tetrafluoroborates
Authors: Szafrańska Barbara , Pająk Zdzisław
Published: February 2015

Proton and fluorine NMR second moments and spin-lattice relaxation times for polycrystalline tetraethyl-and tetrapropylammonium tetrafluoroborates have been measured over a wide range of temperatures. Solid-solid phase transitions were found for both compounds and confirmed by DSC. Methyl group C3 reorientation followed by more complex cation motions was evidenced in the low temperature phases. Overall cation reorientation characterises the high temperature phases of both compounds. Isotropic anion reorientation was found in both salts in both phases.
Dielectric Relaxation Studies of 5PCH by the Time Domain Spectroscopy Method
Authors: Gestblom Bo , Urban Stanislaw
Published: February 2015

The time domain spectroscopy (TDS) method has been used for the measurement of the complex dielectric permittivity in the isotropic phase and for perpendicular and parallel orientations in the nematic phase of 5PCH (4-(trans-4-pentyl-cyclohexyl)-benzonitrile). The accessible frequencies range from ca 15 MHz to ca. 1.5 GHz. The obtained spectra are well consistent with the spectra measured recently in the frequency domain (T. Brückert et al., Mol. Cryst. Liq. Cryst., in press). From the relaxation times τ‖, τ⊥and τis we have calculated the activation enthalpies and the retardation factors g|| and g⊥ that allow to obtain the nematic potential q. The validity of some assump­ tions of the mean-field theories of the nematic state are discussed.
Quantum Mechanics Derived from Boltzmann's Equation for the Planck Aether
Authors: Winterberg F.
Published: February 2015

In the Planck aether hypothesis it is assumed that space is densely filled with an equal number of locally interacting positive and negative Planck masses obeying a nonrelativistic law of motion. If described by a quantum mechanical two-component nonrelativistic nonlinear operator field equation, this model has a spectrum of particles greatly resembling the particles of the standard model, with Lorentz invariance as a derived dynamical symmetry valid in the limit of energies small com­ pared to the Planck energy.

Here we show that quantum mechanics itself can be derived from the Newtonian mechanics of the Planck aether as an approximate solution of the Boltzmann equation for the positive and negative Planck masses, with departures from quantum mechanics suppressed by the Planck length.
High-Frequency Conductivity Plateau and Ionic Hopping Processes in a Ternary Lithium Borate Glass
Authors: Cramer C. , Funke K. , Saatkamp T. , Wilmer D. , Ingram M. D.
Published: February 2015

Complete conductivity spectra of a lithium ion conducting glass of composition B2O3-0.56Li2O - 0.45 LiBr have been taken at twelve temperatures from 173 K to 573 K, covering the frequency range from a few Hertz up to about 50 THz. For the first time, a separation of the hopping and vibrational contributions to the spectra has been performed. The resulting frequency dependent hopping conductivity displays a high-frequency plateau similar to those known to exist in crystalline solid electrolytes like RbAg4I5 and Na-β-alumina. In the dispersive regime of the conductivity, there is an increase of the apparent power-law exponent from p = 0.6 to q = 1.3. The spectra are evaluated by combined application of the jump relaxation model and the dynamic structure model. Besides the translational hopping of the lithium ions via the preferred Ā sites, more localized kinds of motion are also detected, viz., hops into the less favoured C̄ sites (and mostly back again) as well as smaller displacements of the ions within their local environment.
The 33S Nuclear Quadrupole Hyperfine Coupling in the Rotational Spectrum of 33S Dimethylsulfoxide
Authors: Kretschmer U.
Published: February 2015

The rotational spectrum of the 33S dimethylsulfoxide in natural isotopic abundance has been studied using molecular beam Fourier transform microwave spectroscopy. Rotational and quadrupole coupling constants could be extracted from the spectra. They were found to be A = 7017.5456(16) MHz, B = 6894.5117(17) MHz, C=4218.14115(84) MHz, χaa-15.720(18) MHz, χbb= -17.045(23), and χcc = 32.765(25) MHz.
Short-Range Order Details of Metaphosphate Glasses Studied by Pulsed Neutron Scattering
Authors: Hoppe Uwe , Walter Günter , Stachel Dörte , Hannon Alex. C.
Published: February 2015

Details of the short-range order of the binary metaphosphate glasses AIP3O9 and PbP2O6 and the ternary glass system ZnO-MgO-2P2O5 have been studied by pulsed neutron scattering which provides a measuring range up to about Qmax = 500 nm-1. The splitting of the P-O peak in the distance correlation functions attributable to the different bond lengths for the non-bridging and bridging oxygens was found to decrease with increasing field strength of the network-modifier cations. For the ternary system ZnO-MgO-2P2O5 the peak in the distance correlation function, T(r), produced by the first oxygen neighbours around Zn2+ and Mg2+ was separated by the additional use of the X-ray structure factor. The distances rZn0 and rMgO extracted from the separated peaks are slightly different from those obtained from the binary glasses ZnP2O6 and MgP2O6. The metal-oxygen coordination numbers were found to be NZnO=4.5 and NMgO = 5.5. For the two binary systems the coordination numbers Al-0 and Pb-0 were obtained to be 7 and 5, respectively.
Action Integrals for Ellipsoidal Billiards
Authors: Richter Peter H. , Wittek Andreas , Kharlamov Mikhail P. , Kharlamov Alexej P.
Published: February 2015

Integrable billiards in ellipsoidal and related shapes are discussed. The emphasis is on the computation and graphic presentation of energy surfaces in the space of action variables. Explicit results, including figures, are given for spheres, circular cylinders, planar ellipses, prolate and oblate ellipsoids.
81Br Nuclear Quadrupole Relaxation in Aluminium Tribromide
Authors: Okubo Noriaki , Igarashi Mutsuo , Yoshizaki Ryozo
Published: February 2015

The 81Br nuclear spin-lattice relaxation time in AlBr3 has been measured between 8 K and room temperature. The result is analyzed using the theory of the Raman process based on covalency. A Debye temperature of 67.6 K and covalency of 0.070 and 0.072 for terminal and 0.022 for bridging bonds are obtained. The correspondence of the latter values to those obtained from the NQR frequencies is low, in contrast to the previously examined compounds.
1H and 19F NMR Study of Cation and Anion Motions in Guanidinium Fluoroantimonates
Authors: Grottel M. , Kozak A. , Pająk Z.
Published: February 2015

Proton and fluorine NMR linewidths, second moments, and spin-lattice relaxation times of polycrystalline [C(NH2)3]2SbF5 and C(NH2)3SbF6 were studied in a wide temperature range. For the pentafluoroantimonate, C3-reorientation of the guanidinium cation and C4-reorientation of the SbF5 anion were revealed and their activation parameters determined. The dynamical inequivalence of the two guanidinium cations was evidenced. For the hexafluoroantimonate, two solid-solid phase transitions were found. In the low temperature phase the guanidinium cation undergoes C3 reorien­ tation while the SbF6 anion reorients isotropically. The respective activation parameters were derived. At high temperatures new ionic plastic phases were evidenced.
Structure and Dynamics of Crystal Solvates Hexaphenylditin • 2X, X=Benzene , Toluene, Fluorobenzene , Chlorobenzene , and Aniline. An X-Ray, P(VAPOR)=ƒ(T)> and 2H NMR Study
Authors: Eckardt Karin , Fuess Hartmut , Hattori Masakazu , Ikeda Ryuichi , Ohki Hiroshi , Weiss Alarich
Published: February 2015

The crystal structures of the hexaphenylditin (hpdt) solvate compounds, (C6H5)3Sn-Sn (C6H5)3 • 2X, solvent X = aniline (an), chlorobenzene (cb), fluorobenzene (fb), and toluene (to), were determined. They are isomorphous with the known benzene (be) crystal solvate compound hpdt • 2be, crystallizing in the trigonal space group R3̅, with Z=3 formula units per unit cell. The lattice constants (in pm), from X-ray powder diffraction, are: hpdt • 2an (1): a= 1170.01 (9), c = 2641.49 (20), c/a = 2.2577; hpdt • 2be (2): a = 1165.45 (5), c = 2641.30 (9), c/a = 2.2663; hpdt • 2cb (3): 0=1175.88(5), c = 2661.66(10), c/a = 2.2635; hpdt • 2fb (4): 0 = 1167.69(5), c = 2643.21 (9), c/a = 2.2636; hpdt • 2to (5): a=1182.24 (7), c = 2649.13(11), c/a = 2.2408. The single crystal structure determination of 5 leads to a = 1180.2(2), c = 2651.4 (5). The decomposition of 5 results in the monoclinic phase of hexaphenylditin. Vapor pressure measurements p=ƒ(T), 260 <̲ T/K <̲350, of the compounds have been performed and the heats of vaporization ΔHv/kJmole-1 were determined: 52.44 (1), 46.65 (2), 34.52 (3), 43.08 (4), 55.30 (5). The dynamics of the host molecules C6D6, C6D5CD3 and C6H5ND2 were studied by 2H NMR in the range 295 <̲ T/K <̲ 118. The rotation of the benzene molecule about its threefold axis is maintained till 118 K; in the case of toluene the rotation of the phenyl ring about the pseudo-threefold axis freezes in below 180 K, while the methyl group still rotates about its threefold axis till 123 K.
Direct Determination of the Local Structure in Molten Alumina by High Temperature X-Ray Diffraction
Authors: Waseda Y. , Sugiyama K. , Toguri J. M.
Published: February 2015

A high temperature X-ray diffraction study of molten alumina has been carried out at 2363 K (2090°C). The local ordering parameters in molten alumina were estimated by using the interference function refining technique. Octahedrally coordinated aluminum is suggested to remain in the melt as the fundamental local structure.
Comparison of ESR Spectra of Two Cu(II) Salts in Some Amide Solutions
Authors: Robers B. , Stockhausen M.
Published: February 2015

X-band ESR spectra of liquid solutions of Cu(II)nitrate and Cu(II)chloride in N-methyl-formamide and four N,N-disubstituted amides are reported and discussed with respect to the occurrence of ion pairs or higher ionic aggregations. Nitrate solutions allow to distinguish two complex types of moderate asymmetry at most. Chloride solutions indicate a succession of at least three complex types with strongly increasing asymmetry.
Static Permittivity and Association in Mixtures of Mono- and Dihydric Alcohols
Authors: Hanna F.F. , Shafik A.H. , Stockhausen M.
Published: February 2015

The static permittivity has been measured for n-hexanol and n-dodecanol in heptane solution on admixture of a mi­ nor (fixed) fraction of a dihydric alcohol (ethanediol, 1,6-hexanediol or 1,12-dodecanediol) from low to medium total alcohol concentrations. The 20°C dispersion steps are re­ ported. They show a more or less pronounced intensification due to the additive, which unexpectedly is smaller on addi­tion of two diols together than of only one diol. Probably this reflects competing self- and hetero-association equilibria.
Bubble Formation in Superposed Magnetic Fluids in the Presence of Heat and Mass Transfer
Authors: Gill Gurpreet K. , Chhabra R.K. , Trehan S.K.
Published: February 2015

In this paper we study the nonlinear Rayleigh-Taylor instability in the case of magnetic fluids in the presence of heat and mass transfer. We find that there is a normal field instability in the linear case. The behaviour of the bubbles in the nonlinear analysis is the same as if they were leaving the surface when the liquid is superheated. The criterion for "Explosive Instability" is also examined.
Pressure Dependence of the Dielectric Anisotropy of 5CB and 6CB
Authors: Urban Stanislaw
Published: February 2015

The pressure-dependence of the dielectric anisotropy, Δε = ε0|| - ε0⊥, of two nematogens, n-pentyl-and n-hexyl-cyanobiphenyl (5CB and 6CB) has been measured at constant temperature. For this purpose a high pressure chamber made of non-magnetic materials was constructed, allowing for the orientation of the samples by a magnetic field. The pressure dependencies of ΔεT were analyzed in the frame of the Maier-Meier equations for the principal permittivity components in the nematic phase. It was found that the relation between Δε and the order parameter S is not properly described by these equations. The Kirkwood correlation factor calculated on the basis of the present results and the Maier-Meier equations is smaller than 0.5, whereas it increases to a more realistic value (~0.7) if the electronic polarization is incorporated in the equations.
X-Ray Diffraction with Molten AuxMn100-x-Alloys
Authors: Hagenmayer R. M. , Lamparter P. , Steeb S.
Published: February 2015

The molten alloys Au28.5Mn71.5 and Au68Mn32 are investigated with the energy dispersive X-ray diffraction method which works rather fast so that the evaporation loss of Mn from the molten alloys is kept low. From the observed prepeak follows that both melts are compound-forming but the gold rich melt Au68Mn32 shows only 50% of the short range order existent within the Au28.5Mn71.5 melt. Total structure factors and total pair correlation functions are discussed.
NMR and FTIR Characterization of Sol-Gel Derived Ternary Oxide Glasses in the System BaO–TIO2–SiO2
Authors: Feike M. , Meise-Gresch K. , Chen Qi , Frischat G.H.
Published: February 2015

The annealing history of glasses in the system (20-40) BaO-40TiO2(40-20)SiO2 has been mon­itored by 29Si MAS NMR and FTIR spectroscopy from the dried gel to the final glassy state. Assignment of chemical shifts to specific building units has been facilitated by comparative studies of the limiting less complex binary silicate systems. From the NMR spectra at various compositions appreciable condensation to a three-dimensional network is inferred already at low drying temper­atures. Processes like the pyrolysis of acetate rests of the starting materials and modification of the silicate structure due to Ba2+ cations have been mirrored in the spectra of both methods for samples annealed at intermediate temperatures. The microstructure of the final gel glass of the ternary system has been determined spectroscopically to consist of silicate and titanate species typical of crystalline fresnoite, whereas remaining amounts of TiO2 and SiO2 develop a separate network each. Only small amounts of Si-O-Ti linkages have been recognized in the vibrational absorptions; they vanish at higher annealing stages.
Nuclear Magnetic Resonance Measurements in Oil-Nitrogen Two-Phase Flow
Authors: Krüger G. J. , Birke A.
Published: February 2015

NMR measurements of the oil mass flow have been carried out in all-oil flow as well as in oil-nitrogen two-phase flow. For the calibration a simplified method was used which circumvents spin-lattice relaxation calculations due to the short polarization time of the protons at rather high flow velocities. With this method an overall accuracy of the oil-flow in oil-nitrogen two-phase flow of about ±5% was achieved.

Some proposals for an improvement of the NMR apparatus are made, which would render the evaluations simpler and more accurate.
Enumeration of the Staggered Conformers of Alkanes
Authors: Cyvin S.J. , Brunvoll J. , Cyvin B.N. , Lüttke W.
Published: February 2015

Alkanoid systems are chemical graphs which can be embedded in the diamond lattice. They correspond to the staggered conformers of alkanes. Non-overlapping and overlapping systems are defined. The previously deduced algebraic solution for the numbers of unbranched alkanoids is revisited and reformulated in terms of generating functions. Computerized enumerations for non-overlapping alkanoids, both unbranched and branched, are reported. Some of the smallest overlap­ ping unbranched alkanoids are generated by a method called combinatorial constructions.
Influence of Temperature and Oxygen Concentration on the Radiation Induced Oxidation of Phenylalanine
Authors: Krajnik P. , Quint R. M. , Solar S. , Getoff N. , Sontag G.
Published: February 2015

The formation of tyrosine isomers by γ-radiolysis of neutral aqueous phenylalanine solutions was found to be strongly dependent on oxygen concentration and temperature. Changing the dose rate did not influence the degradation process. In the presence of 0.25 x 10-3 mol dm-3 oxygen at room temperature the yields of o-tyrosine as well as of m- and p-tyrosine drop from G(o-Tyr) = 0.5 and G(m-Tyr) = G(p-Tyr) = 0.4 at a dose of 0.3 kGy to 0.18 and 0.16 at 2.5 kGy, respectively. In solutions containing 1.25 x 10-3 mol dm-3 oxygen the initial yields remain unchanged but decrease at 2.5 kGy only to G(o-Tyr) = 0.3 and G(m-Tyr) = G(p-Tyr) = 0.20. Under the latter reaction conditions also 3,4-dihydroxyphenylalanine was found.

Samples irradiated in frozen state did not show remarkable radiolysis of phenylalanine and tyrosine formation. In the range between 5 and 20°C no essential influence of temperature on the phenylalanine radiolysis and tyrosine yields was observable. The obtained results are important for methods using the tyrosine yields as markers for the detection of irradiated food. Storage conditions and irradiation temperature play an essential role on radiation induced changes of food.
Electronic Raman Spectra of a Low-Spin FeIII Porphyrin and Reexamination of the Vibrational Spectra of K3[Fe(CN)6] and [Fe(C5H5)2]BF4
Authors: Sievertsen Svend , Galich Lutz , Homborg Heiner
Published: February 2015

The resonance Raman spectra of (nBu4N)[Fe(CN)2TPP] ((nBu4: tetra(n-butyl)ammonium; TPP: m-tetraphenylporphyrin), K3 [Fe(CN)6] and [Fe(C5H5)2]BF4 have been investigated. A molecular electronic Raman (ER) effect at 545 cm-1 is observed for (nBu4N)[Fe(CN)2TPP]. The transition occurs between lower “Γ7” and upper “Γ8” level of the spin-orbit split ground state assuming pseudo-octahedral symmetry. In contrast to earlier studies no ER effect is detected for K3[Fe(CN)6] and [Fe(C5H5)2]BF4. For Raman shifts < 800 cm-1 only one strong Raman line is observed for [Fe(C5H5)2]BF4 at 311 cm-1, assigned to the iron ring stretch designated by ν4 (a1g in D5d). Due to a phase transition of K3[Fe(CN)6], two additional strong vibrational lines at 329 and 352 cm-1 appear in the Raman spectrum taken at 10 K. Their intensities show A "term" behaviour of the resonance Raman effect with overtones and combinations for both lines. These are components of the vibronic combinations with the ν6, ν7, and ν8 modes (t1u in Oh) in the IR spectra, too.
Dielectric Properties and Characterisation of the Superionic Phase of [C(NH2)3]2SbCl5*[C(NH2)3]Cl (GHCA)
Authors: Zaleski J. , Bator G. , Jakubas R.
Published: February 2015

GHCA undergoes four phase transitions at Tc1 = 402 K, Tc2 = 373 K, Tc3 = 162 K, and Tc4 = 146 K. Below Tc3 it possesses pyroelectric properties with the spontaneous polarization vector (Ps) in the ac plane and the maximum along the c axis equal to 8 μC/m2. Dielectric dispersion studies of GHCA show that the main dielectric dispersion connected probably with collective motions of chlorine ions is above 1GHz. For the phase transition at Tc2 to a superionic phase the thermal dilatation and electric conductivity were measured. The anomalies of the electric conductivity at Tc2 and Tc1 were observed with large values of σ(10-3 S/m) above Tc3. The guanidinium cations above Tc2, besides reorientational motions, undergo slow self diffusion.
Phase Diagrams of Binary Systems of Some Alkali Iso–Butyrates with One Mesogenic Component
Authors: Mirnaya T. A. , Yaremchuk G. G. , Volkov S. V.
Published: February 2015

The phase diagrams of the binary mixtures of mesogenic potassium iso-butyrate with non-mesogenic lithium-, sodium-, and caesium iso-butyrate have been investigated by differential thermal analysis and hot stage polarization microscopy. The temperature and concentration ranges of liquid crystal formation have been established. Sodium and caesium iso-butyrate have been found to possess latent mesogenic properties.
Determination of Particle Densities and Line Profiles in Plasmas by Resonance Interferometry: A Feasibility Study using Computer Simulated Refractivity Data
Authors: Haas C. , Pretzier G. , Jäger H.
Published: February 2015

The principles of resonance interferometry are described with regard to two applications: High accuracy particle density determination within plasmas and interferometrical determination of spectral line profiles. The usability of this technique is investigated numerically, and physical limits are given for the regions in which resonance interferometry may be employed successfully. The discussion and the results are helt general for making it possible to decide whether or not to apply this method for an actual problem. An example (an object being longitudinally homogeneous with respect to the direction of light: end-on observation) shows how to use the presented results for calculating the detection limits of the method for a given object geometry.
Dynamic Modelling of Heart Beat
Authors: Grossmann Siegfried , Ranft Sabine
Published: February 2015

Two recently introduced methods to analyze heart beat are checked by applying them to numerically produced time series representing artificial heart beat. The phase space diagram method (G. E. Morfill, G. Schmidt) depends on the variability of the sinus rhythm and the coupling interval of the extrasystoles. The risk index method (J. Kurths et al.) seems to measure different aspects of heart beat.
Can Twisted Internal Charge-Transfer(TICT)State be Formed in Rigid Polymers?
Authors: Kawski A. , Piszczek G. , Kukliński B.
Published: February 2015

Absorption, emission and emission anisotropy spectra of 4-cyano-N,N-dimethylaniline (CDMA) and 4-cyano-2,6,N,N-tetramethylaniline (CTMA) were investigated in polyvinyl alcohol) (PVA) films. It was found that the CDMA and CTMA molecules in PVA films at room temperature display phosphorescence, the emission band of which overlaps with the longwave fluorescence band a. The low value of the emission anisotropy shows that in the rigid PVA matrix there are microscopic defects in the form of empty spaces in which a certain fraction of the CDMA or CTMA molecules can attain twisted intramolecular charge-transfer states (TICT) due to rotational relaxation. The emission anisotropies in the shortwave, b, and longwave, a, fluorescence bands of CDMA in propylene glycol were found to be distinctly different, this indicating that the directions of the transition moments are not parallel.
EPR of VO2+Doped Cd2ZrF8• 6H2O SingleCrystals
Authors: Jayaram Geetha , Krishnan V. G.
Published: February 2015

X-band EPR measurements have been carried out on VO2+ doped single crystals of Cd,ZrF8 • 6H20. The angular variation of the 19F superhyperfine structure did show that the VO2+ ion occupies an interstitial site with C4v symmetry.
Off-Resonance Nutation NQR Spectroscopy of Powders
Authors: Sinjavsky N.Ja.
Published: February 2015

The peculiarities of nutation NQR spectra of nuclei with spin I=3/2 in powders are considered in the case of a resonance offset. An equation, which takes into account the offset is given for the determination of the asymmetry η. It is shown that structural of monocrystals by means of nutation spectroscopy are possible.
Phase Diagrams of Binary Systems of Non-Mesogenic Components:Caesium-Sodium and Caesium—Lithium Iso-Butyrates
Authors: Mirnaya T. A. , Yaremchuck G. G. , Volkov S. V.
Published: February 2015

The phase diagrams of the binary systems given in the title have been studied by differential thermal analyses and hot stage polarization microscopy. Smectic liquid crystals are found in some composition ranges of the binary with sodium iso-butyrate. The liquid crystal appearance in this system is explained by latent mesomorphism of both components and by the additional electrostatic stabilization of the ionic mesophase because of dissimilar cation interactions. The unlike conditions for the exhibition of latent mesomorphism of caesium isobutyrate in the two systems is discussed.
Notiz: Decelerated β-Decay of Tritium Solved in Titanium
Authors: Reifenschweiler Otto
Published: February 2015

It is shown that it is not possible to explain the measured decrease of tritium radioactivity by a change between ad­ sorption at the surface and bulk absorption in small titanium particles as argued in a recent note in this periodical. As to the reduction of titanium oxide by tritium, it is pointed out that the enthalpy of formation of titanium oxide is nearly 4 times that of water.
Notiz: No Reduced Radioactivity of Tritium in Small Titanium Particles
Authors: Wicke Ewald
Published: February 2015

The experimental results of O. Reifenschweiler are ex­plained by the known reactions between hydrogen and tita­nium under careful distinction of the effects at the surface and in the bulk.
On the Analysis of Twisted Director Configurations
Authors: Kilian A. , Sonnet A.
Published: February 2015

A twist tensor (T-tensor) is introduced, which is defined for differentiable vector and director fields. Its eigensystem describes the local helical structure of the underlying field. It can have up to two nonzero eigenvalues, which indicate whether the local structure is untwisted, helical or double-twisted. The eigenvalues q
i, if real valued, are the helical wave numbers, and the corresponding eigenvectors represent the local twist axes. The T-tensor can serve as a tool to analyze director configurations in chiral nematic liquid crystals, and applications in computational fluid dynamics seem feasible.
Algebraic Approach to the Fixed Point Structure of the Quantum Mechanical Dirac -Coulomb System
Authors: Nag Nivedita , Roychoudhury Rajkumar
Published: February 2015

It is shown that a non-perturbative ß like function can be obtained for a Dirac-Coulomb system with both vector and scalar couplings using the properties of 0(2,1) algebra and the tilting operator mechanism.
High Voltage Plane Cathode -Comb Anode Discharge
Authors: Mezei P.
Published: February 2015

Investigations on the characteristics of a plane cathode-comb anode discharge are presented. This discharge arrangement consists of a plane cathode with a series of anodes, resembling a comb, above it. A significant increase of the discharge voltage was obtained by increasing the number of comb-teeth. Voltage-current characteristics, the intensity and the spatial distribution of He, Al, and Ar spectral lines were investigated as functions of the number of comb-teeth, He pressure and discharge current. Due to the increase of discharge voltage, the spectral line intensities increased significantly in the negative glow region. In case of the Al-I 396.1 nm and the He-I 318.7 nm lines an intensity peak was observed also in the cathode glow region. This peak was pronounced in the case of high voltage anode arrangements and is attributed to excitation by positive ions.
Friction Drag on a Cylinder Moving in a Nematic Liquid Crystal
Authors: Ruhwandl R. W. , Terentjev E. M.
Published: February 2015

The flow of a liquid crystal around a body depends not only on the geometry of the body but also on the director field around it. For low-Ericksen number flows, the director distribution largely remains in its static equilibrium texture (along a uniform direction far away from the body and, for instance, perpendicular to its surface). We calculate the velocity and pressure of a cylinder in a nematic flow numerically, taking into account topological defects on the particle surface and find the drag force acting on the moving body. The drag force is, in general, non-central, i.e. not aligned with the direction of motion. The lift component of the drag force is a measure for the anisotropy of the system. We show that due to the realistic director texture the drag force is larger than previously thought and the anisotropy, F
II/F
^, smaller and decreasing while approaching the nematic clearing point.
Three Theorems for the Spectroscopic -Kinetic Analysis of Chemical Reactions
Authors: Mauser H. , Polster J.
Published: February 2015

The results obtained in the last 25-30 years for the spectroscopic-kinetic analysis of reaction systems using absorbance (A) diagrams and the method of formal integration are summarised in three theorems.

Theorem 1: A reaction mechanism can be experimentally disproved but not proved.

Theorem 2: Two strictly linear reaction systems having the same number of linearly independent reaction steps can not be distinguished from each other by purely spectroscopic means.

Theorem 3: Thermally controlled reaction systems which consist of two linearly independent reaction steps -one step of which is at least a reaction of second order -can not be distinguished from each other by purely spectroscopic means if their eigenvalues have the same functional dependence on the initial concentrations.

The advantages of the formalism presented are demonstrated using the photoreduction of anthraquinone-2-carbonic acid in alkaline methanolic solution.