bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Motion in Solid Tetrabutylammonium Tetrafluoroborate
Authors: Szafranska B. , Kozak A. , Pająk Z.
Published: February 2015

Proton and fluorine NMR second moments and spin-lattice relaxation times for polycrystalline tetrabutylammonium tetrafluoroborate have been measured over a wide range of temperatures at several Larmor frequencies. An analysis of cross-relaxation effects results in a determination of activation parameters for anion and cation reorientations. Three solid phases characterized by different ion dynamics are evidence
Substratum Interpretation of the Quark-Lepton Symmetries in the Planck Aether Model of a Unified Field Theory
Authors: Winterberg F.
Published: February 2015

An attempt is made to explain the observed quark-lepton symmetries in the framework of the recently proposed Planck aether model of a unfied field theory. If the many body lepton wave function can rearrange itself into a vortex-substructure, very much as it has been observed in the fractional quantum Hall effect, all the symmetries can be understood by the quantum numbers of these vortices and their interactions, and all fermions as permitted combinations of those vortices, including the correct number of force-transmitting bosons. The proposed model can also give a value for the mass of the intermediate vector boson. All charges are explained by the quantum mechanical zero point fluctuations of the Planck masses making up the Planck aether
Notizen: Acoustic Gravity Vortices in the Atmosphere
Authors: Stenflo L.
Published: February 2015

It is pointed out that the theory for acoustic-gravity vortices is applicable to recent observations of very large amplitude solitary waves in the atmosphere
Stokes Modes in Taylor-Couette Geometry
Authors: Gebhardt Thomas , Grossmann Siegfried
Published: February 2015

The eigenvalue problem of the Stokes operator is solved for an incompressible fluid contained between two coaxial cylinders of infinite height. Flow field patterns and spectra of the eigenmodes ("Stokes modes") are offered. Furthermore, in finite dimensional subspaces generated by these Stokes modes, the eigenproblem for the Navier-Stokes operator linearized about the laminar Taylor-Couette flow is studied. Although the spectrum's qualitative features are still correct, we quantitatively obtain wrong results. We trace this back to a Gibbs like phenomenon of higher order derivatives of the flow field as probable source, since the Stokes modes do not reflect the discontinuity arising from different velocities at both cylinders
Deuterium NMR Study of the Solid-Solid Phase Transition in Phenethylammonium Bromide
Authors: Gruwel Marco L. H. , Wasylishen Roderick E.
Published: February 2015

Using 2H NMR, the dynamics of the cation in phenethylammonium bromide were studied in the two solid phases. Line shape and spin-lattice relaxation rate studies of the ammonium headgroups and the adajacent methylene groups indicate the onset of alkyl-chain motion prior to the first order phase transition. In the low-temperature phase the line shape and the spin-lattice relaxation rates of the -ND3 groups are consistent with C3 jumps and an activation energy of 54±4 kJ mol-1. However, in the high-temperature phase the spin-lattice relaxation studies indicate the presence of small-angle diffusion of the -ND3 groups around the C3 symmetry axis. In this phase the -CD2- groups show line shapes typical of large-amplitude two-site jumps occurring at a rate > 107 s-1 . In the low-temperature phase, at temperatures below 295 K, the -CD2
- 2H NMR line shapes indicate that the C - D bonds are essentially static
Wave Function Collapse as a Real Physical Phenomenon Caused by Vacuum Fluctuations Near the Planck Scale
Authors: Winterberg F.
Published: February 2015

It is hypothesized that the collapse of the wave function is a real physical phenomenon caused by vacuum fluctuations near the Planck scale. The hypothesis is suggested by a recently proposed model (Planck aether model) according to which the fundamental kinematic symmetry is the Galilei-group with the Lorentz invariance as a derived dynamic symmetry. The proposed model has the goal to derive all fields and their interactions from an exactly nonrelativistic operator field equation, resembling Heisenberg's relativistic spinor field equation. In this model the groundstate of the vacuum is a superfluid consisting of an equal number of positive and negative Planck masses interacting via delta function potentials and making the cosmological constant equal to zero. Gauge bosons come from transverse waves propagating in a lattice of quantized vortices, and spinors are explained in this model as exciton-like quasiparticles held together by gauge bosons. Because vector gauge bosons move in the model with the velocity of light, objects held together by the forcc fields of these bosons obey Lorentz invariance as a dynamic symmetry. With the longitudinal wave modes moving with a superluminal phase velocity at energies near the Planck scale, it is conjectured that the quantum mechanical wave function is real and that its collapse results from the entrapment of the wave function by these longitudinal superluminal wave modes. Because these modes occur near the Planck scale their very large zero point fluctuations might therefore trigger the collapse even through dense matter. But because the fluctuations are finite, and because the wave modes have a finite albeit very large phase velocity, the quantum mechanical correlations would be broken above a ccrtain finite length. In the limit of a vanishing Planck length, and hence vanishing gravitational constant G, the phase velocity would become infinite, and the same would be true for the length above which the correlations are broken. One therefore may say that in the limit G = 0 the collapse is infinitely fast and that in this limit the correlations are not broken even over arbitrarily large distances
Structural Properties of the Ion-Dipole Model of Electrolyte Solutions in the Bulk and Near a Charged Hard Wall.Application of the Truncated Optimized Cluster Series
Authors: Pizio O. A. , Halytch Z. B.
Published: February 2015

An ion-dipole model of electrolyte solutions in the bulk case and near a charged or uncharged hard wall is considered. A method to derive the terms of optimized cluster expansions for the distribution functions of ions and dipoles which provides a set of approximations beyond the mean spherical approximation is given. The third cluster coefficient approximation is investigated
Molecular Reorientation in Liquid Methanol
Authors: Ludwig R. , Gill D. S. , Zeidler M. D.
Published: February 2015

Oxygen-17 enriched methanol CD3
17OH was synthesized and 1H as well as 17O nmr relaxation rates were measured in the temperature range 180-310 K. By varying the 17O-content different contributions to the proton relaxation rate could be separated and from the 17O-H dipolar interaction contribution the correlation time of the OH bond was determined. These results are compared to recent computer simulation data. Additional deuteron relaxation measurements on CH3OD yielded the quadrupole coupling constant which increases with falling temperature. The 17O quadrupole coupling constant shows a similar trend with temperature but not as pronounced.
The Structure of Aqueous Electrolyte Solutions: Comparis on of Computer Simulation and Experiment
Authors: Neilson G. W.
Published: February 2015

This review compares results of neutron and X-ray diffraction experiments with computer simulation and theoretical calculation for aqueous electrolyte solutions at the atomic level in terms of the partial radial distribution functions of several ionic solutions, and includes results for the ion-water and ion-ion structure of systems containing alkali ions, alkaline earth ions, transition metal cations and a few anions
The Conductance of Naland Tetraethylammonium Iodide in Mixtures of Methanol with Acetonitrile and Water
Authors: Hawlicka E. , Grabowski R.
Published: February 2015

The conductance of Nal and Et4NI in methanol-acetonitrile and methanol-water mixtures was measured at 25 ± 0.005 °C for the whole range of the solvent compositions, the salt molarity ranging from 5 • 10-5 up to 1 • 10-2. Several equations describing the influence of the salt concentration on the equivalent conductance are examined and the Fuoss-Hsia equation with the Fernandez-Prini parameters is found to be the most appropriate one for systems with weak ionic association. Variations with the solvent composition of the limiting equivalent conductance, the distance between ions forming ion pairs and the association constant are discussed. Nonmonotonous changes of the association constant are concluded to be a feature of microheterogenous systems.
Computer Simulation Studies of the Adsorption of Water on a Metal Surface
Authors: Spohr E. , Wolfsberg M. , Bopp P.
Published: February 2015

We report computer simulations of the adsorption process of water on a platinum (100) surface. At very low impact energies the sticking coefficient approaches unity in agreement with experimental evidence. The sticking coefficient for the bare surface decreases strongly with increasing impact energy already in the energy range <0.5 eV and also with increasing surface temperature. At all but the lowest impact energies the sticking coefficient increases drastically if the impact zone of the approaching molecule is in the vicinity of preadsorbed water molecule(s). The reason for this phenomenon is efficient energy transfer into water-water degrees of freedom and/or into the metal O "bond" of the preadsorbed water molecules. In the present study, where surface diffusion does not play an important role because the impact zone is chosen to be close to the adsorbed molecule or cluster, hydrogen bonds are formed between incoming and preadsorbed molecules during approach and impact. Excess energy is transferred into the lattice within a few picoseconds leading to a two-dimensional hydrogen bonded water cluster.
The Effect of Bivalent Cations in the Adsorption of Phosphonic Acids on Iron Electrodes Studied by the Radiotracer Method
Authors: Kármán F. H. , Kálmán E. , Várallyai L. , Kónya J.
Published: February 2015

The adsorption of 1-hydroxyethylidene-1,1 -diphosphonic acid (HEDP) on an iron electrode in neutral aqueous solution has been examined by the radiotracer method. The role of calcium and zinc cations in the adsorption mechanism has also been studied in order to understand the synergistic effect when HEDP is applied together with these cations
Thermodynamic Theory for Binary Fluid Mixtures in the Gravitational Field
Authors: Schröer Wolffram
Published: February 2015

The thermodynamic theory for a fluid mixture in a gravitational field under a given pressure is developed. The local density and the local molfraction are varied to minimize the Gibbs free energy of the system. With the approximation of local thermodynamics, a set of coupled linear differential equations of first order is obtained. The non-local van der Waals-Landau contributions, leading to a set of linear differential equations of second order, are discussed for the two component lattice gas. Experimental methods allowing to determine concentration and density gradients are discussed also.
High-Resolution Vibrational Spectra of Furazan
Authors: Stiefvater Otto L.
Published: February 2015

The study by Fourier transform (FT) infrared (IR) spectroscopy of the fundamental vibrational bands v12 and v5 of furazan yields the origins of these bands with a statistical uncertainty of 10-6 cm-1, which leads to an estimated absolute uncertainty of 10-4 cm-1. The values are v°12 = 952.6123 cm -1 and v°5 = 1.005.3536 cm -1. They confirm the values previously deduced from laser/microwave double resonance (LMDR) experiments. Previous results for the molecular constants of the vibrational ground state and of the two vibrationally excited states, as obtained by double resonance modulation (DRM) microwave spectroscopy alone, are confirmed and refined. Advantages brought about through the combination of the DRM microwave and the FT-IR technique are outlined.
Über die Wurzelaus der Klein-Gordon-Gleichung als Schrödinger-Gleichung eines relativistischen Spin-0 -Teilchens
Authors: Briegel H.-J. , Englert B.-G. , Michaelis M. , Süssmann G.
Published: February 2015

Die explizite Form des nichtlokalen Operators [(mc)2 - (hṼ)2]1/2 als integraloperator wird für m≧0 auf Cx
c (ℝ3) berechnet. Das Eigenwertproblem

wird für δ- artige Potentiale und für den Oszillator diskutiert
Studies of Polymer Solvation by Dielectric Relaxation Spectroscopy IV:Polyvinylpyrrolidone in Urea Derivatives at Different Temperatures
Authors: Rohmann M. , Stockhausen M.
Published: February 2015

The dielectric spectrum is measured up to 72 GHz of solutions of polyvinylpyrrolidone (PVP) in tetramethylurea (TMU), dimethylethylene urea and dimethylpropylene urea. Concentrations are up to a monomole fraction of 0.65 (PVP 1200) or 0.5 (PVP 40 000). Measuring temperatures are 20CC for all systems and additionally 40 and 60°C for the TMU solutions. For the description of the results a superposition of Debye type components is used, which are discussed in particular with respect to the solvent contributions. These can be distinguished into three regions: (i) Unaffected bulk-type; (ii) loosely affected, relaxation time and activation enthalpy increasing with increasing polymer content; (iii) quasi bound and moving together with the polymer. The solvation numbers (total of affected solvent per repeat unit of polymer) are about 1.5 to 2.
Kinetic Energy Release and Position of the Transition State for С6Н7
+ Ions Produced from Isomeric C7H8O Precursors
Authors: Selim Ezzat T. M. , Rabbih M. A. , Fahmey M. A.
Published: February 2015

The energetic requirement and mechanisms for CHO' loss from the molecular ions of isomeric C7H8O precursors have been reported. The heat of formation of [C6H7]+ (protonated benzene) was determined and ε* evaluated. Measurement of the kinetic energy release TB gives the energy-partitioning quotients q= TB/εr* which range from 0.38 to 0.99. The energy available and TB are small for the strongly endothermic reaction of benzyl alcohol but increase sharply in the case of the weakly endothermic reaction of anisole. All reactions have "late" transition states, the position X0*of the transition state on the reaction coordinate varying from 0.64 to 0.93
Dyadic Procedure for Planewave Scattering by Simply Moving, Electrically Small, Bianisotropic Spheres
Authors: Lakhtakia Akhlesh
Published: February 2015

A dyadic procedure is given for the planewave scattering response of an electrically small, bianisotropic sphere moving with a constant velocity in free space. Lorentz transformations and the polarizability dyadics of a stationary bianisotropic sphere are used in this procedure
Electrical Conductivity of Molten LaCl3-NaCl, LaCl3-KCl, and LaCl3-CaCl2
Authors: Fukushima K. , Iwadate Y. , Andou Y. , Kawashima T. , Mochinaga J.
Published: February 2015

The electrical conductivities (x's) of molten LaCl3-NaCl, LaCl3-KCl, and LaCl3-CaCl2 were measured at 893-1168 K, by a conventional ac technique and fitted by quadratic functions of temperature. They increase with increasing temperature and decrease with increasing mole fraction of LaCl3. The equivalent conductivities (A's) follow a linear relationship of In A vs. 1/T The A's of LaCl3-NaCl and LaCl3-KCl decrease drastically with increasing LaCl3 concentration. A of molten LaCl3 is smaller than that of molten CaCl2, in which the octahedral complex anion CaCl4-
6 is known to exist. It seems reasonable to assume that complex ions or cluster species such as LaCl3
6- and La2Cl3 exist in molten LaCl3 and its mixture melts. Similar results, reported in a previous paper, were obtained for PrCl3-NaCl, PrCl3-KCl, and PrCl3-CaCl2
Rotational Spectrum of Borane IMonoammoniate: Boron and Nitrogen Hyperfine Structure and Vibrational Structure
Authors: Vormann Kirsten , Dreizler Helmut
Published: February 2015

The boron and the nitrogen hyperfine structure in the rotational spectra of two borane monoammoniate isotopomers, 11BH3NH3 and 11BH3ND3 have been investigated and the quadrupole coupling constants of boron and nitrogen have been determined. It was also possible to determine the spin rotation constants CN of boron. In the spectrum of 11BH3NH3 we observed additional splittings which are not caused by quadrupole coupling. In the spectra of the ammonia dimer, (NH3)2, to our opinion the same kind of splittings occur. As interpretation of this phenomenon it was proposed that two different vibrational states cause the splitting. They were called ■x and ß. We use the same model for 11BH3NH3. The deuterated isotopomer 11BH3ND3 shows the normal spectrum of a symmetric top with two coupling nuclei, similar to the deuterated ammonia dimer (ND3)2. We obtained the following results: 11BH3ND3 in the x vibrational state, l/2(B + C) = 17517.21399(48) MHz, eQqaa(11B) - 2.584 (10) MHz, eQ gaa(14N) = -2.135 (5) MHz, CN(11B) = 4.59 (87) kHz, 11BH3NH3 in the ß vibrational state, 1/2(B + C) - 17517.27706 (52) MHz, eQqaa(11B) = 2.583 (8) MHz, eQqaa(14N) = -2.132 (5) MHz, CN(11B) = 4.76 (99) kHz, and 11BH3ND3, 1/2 (B + C) = 15076.79992 (41) MHz, eQqaa(11B) = 2.550 (7) MHz, eQqaa(14N) = -2.169 (4)"MHz, CN(11B) = 3.42 (67) kHz
Structure and Bonding of Tribromocadmates, ACdBr3, A = NH4, Rb, Cs, CH3NH3, (CH3)2NH2, (CH3)4N], [H2NNH3, and (H2N)3C. An X-ray Diffraction and 79-81Br NQR Study
Authors: Krishnan V. G. , Dou Shi-qi , Weiss Alarich
Published: February 2015

The 79-81Br NQR spectra of tribromocadmates with the cations K⊕, NH4
⊕, Rb⊕, Cs⊕, CH3NH3
⊕, (CH3)2NH2
⊕, (CH3)4N⊕, H2NNH3
⊕, and C(NH2)3
⊕ were studied as functions of temperature from 77 K on up to T>300 K. CsCdBr3 shows a singlet 81Br NQR spectrum over the whole temperature range studied. [CH3NH3]CdBr3, with one 81Br NQR line spectrum at room temperature, experiences a phase transition at 167 K; below this temperature an 18-line spectrum is observed. In [(CH3)4N]CdBr3 (phase II), at 290 K, a singlet 81Br NQR is present as is in the high temperature phase III (TII.1 , = 390 K); the low temperature phase III (TII,m, = 160 K has a triplet 81Br NQR spectrum. KCdBr3 shows an 81Br NQR doublet spectrum, as do RbCdBr3, [H2NNH3]CdBr3, and [C(NH2)3]CdBr3. 81Br NQR triplets are observed for [(CH3)2NH2]CdBr3 and NH4CdBr3. Several crystal structures were determined (at room temperature). [(CH3)4N]CdBr3: P63/m, Z = 2, a - 940 pm, c = 700 pm, disordered cation, single chain Perovskite with face connected [CdBr6]- octahedra (nearly CsNiCl3-type). [(CH3)2NH2]CdBr3: P21/c, Z = 4, a = 898 pm, 6 = 1377 pm, c = 698 pm, ß = 91.2°, face connected [CdBr3-octahedra single chain Perovskite. NH4CdBr3: Pnma, Z = 4, a = 950 pm, b = 417 pm, c= 1557 pm, with a double chain of condensed [CdBr6]-octahedra, NH4CdCl3-type. [N2H5]CdBr3: P2,/c, Z = 4, a = 395 pm, 6 = 1749 pm,c = 997 pm,ß = 94.2°, double chain polyanion similar to NH4CdBr3. [C(NH2)3]CdBr3: C2/c, Z = 4, a = 778 pm, 6 = 1598 pm, c = 746 pm, ß = 110.2°, a single chain Perovskite with a chain of condensed trigonal bipyramids [CdBr5].

Three types of anion chains of CdBr3 have been observed: Single octahedral chains, face connected; double octahedral chains, edge connected; a trigonal-bipyramidal chain, edge connected. The relation between the crystal structure and the Br NQR is discussed
Phase Transitions in the Generalized Entropy Spectrum of Nonhyperbolic Dynamical Systems
Authors: Stoop R.
Published: February 2015

In this contribution, the Generalized Thermodynamic Formalism is applied to a nonhyperbolic dynamical system. The associated generalized entropy function is discussed. The model considered is equipped with a generating partition of two symbols; in contrast to analogous hyperbolic models, the support of the generalized entropy function is two-dimensional. Furthermore, the phase-transition- like behavior caused by the nonhyperbolicity of the measure is shown to lead to the manifestation of a critical line in the surface described by the generalized entropy function. It is discussed how the different combinations of phase-transitions in the more specific entropy spectra fx), SG (ε) and ϕ(λ) are determined by the form of the generalized entropy function
NMR Spin-Lattice Relaxation and Tunnelling of Partially Deuterated Methyl Groups
Authors: Langen H. , Müller-Warmuth W.
Published: February 2015

Proton spin lattice relaxation rates have been measured at 15 and 30 MHz and down to 5 K for the partially deuterated molecular crystals 4-F-toluene, 4-Cl-toluene, and 2,6-Cl2-toluene. The behaviour of these materials is governed by methyl group tunnelling. As compared with the undeuterated compounds, the low temperature relaxation is enhanced and the details depend on the removal of the symmetry coupling between rotator and spin states. The hindering barriers remain unchanged, the A to E conversion rates are faster, and relaxation is dominated by spectral density contributions J(2ωo) and J(2ω0). In one case an additional influence of level-crossing energy transfer on relaxation is observed. Field-cycling spectroscopy reveals steps rather than peaks if the proton spin Zeeman and tunnelling splittings match
Observation of a Heteroelinie Tangeney Crisis in an NMR-Iaser System
Authors: Flepp L. , Finardi M. , Parisi J. , Holzner R. , Badii R. , Brun E.
Published: February 2015

Symbolic-dynamical encoding of chaotic dynamics yields a precise quantitative characterization of the temporal scaling behavior at crisis points. A complete analysis in the heteroclinic tangency case is presented for an NMR-laser
Conductance Studies of Aqueous Succinic Acid
Authors: Apelblat Alexander , Barthel Josef
Published: February 2015

Conductance measurements of aqueous solutions of succinic acid and of di-sodium succinate were performed from 278.15 to 308.15 K and the limiting conductances λ0 (1/2 Succ2- ) are reported. The Waiden product is independent of temperature: λ0(1/2 Succ2-)*η(T) = 0.503 ± 0.001. The salt conductances closely obey the Onsager limiting law. The evaluation of the equilibrium constants for the primary and secondary steps of dissociation, K1 and K2, and the limiting conductances of the hydrosuccinate ion, λ0(HSucc-), are discussed using the Quint and Viallard conductance equation
Luminescence Properties and Electronic Structure of Some Quinolizinone and Indolizinone Derivatives
Authors: Bakalova Sn. , Nikolov P. , Stanoeva E. , Ognyanov V. , Haimova M.
Published: February 2015

The absorption and luminescence static and dynamic properties of a group of quinolizinone and indolizinone derivatives in solvents of different polarity at 297 K and 77 K are studied. On the basis of the spectral data and the PPP quantum-chemical results the problem of the main chromophore in these structures is discussed
Notizen: Stability of the Liquid State of Concentrated Aqueous Solutions of Lithium Salts at Low Temperatures
Authors: Hasebe Tooru , Tanaka Kazuko , Tamamushi Reita , Sato Rie
Published: February 2015

The stability of the liquid state of aqueous lithium salt solutions was studied with a modified DTA technique. Aqueous solutions of LiCl and LiSCN in the concentration range 8-14 mol kg-1 , LiBr in the range 8 - 10 mol kg-1 maintain their liquid state for at least 50 hours at temperatures slightly above their glass transition points
Static and Hydrodynamic Properties of Nematic Liquid Crystals
Authors: Chrzanowska A. , Sokalski K.
Published: February 2015

The static properties of nematic liquid crystals are summarized. The mean field potential emerging from the static distribution function has been used to the hydrodynamic theory. Rotational viscosity coefficients have been investigated. The Parodi relation has been shown to be completely satisfied. Static and hydrodynamic properties have been predicted on the basis of one intermolecular potential
1H and 2H NMR Studies of Mixtures 2,6-Lutidine/Water Near the Lower Critical Solution Point
Authors: Balevicius Vytautas , Weiden Norbert , Weiss Alarich
Published: February 2015

Deuteron spin-lattice relaxation time (TJ measurements of binary mixtures 2,6-lutidine/D20 have been done near the lower critical solution point (TC, L), ε = (T - TC, L)/TC, L ≧10-5. Singularities are observed at TC, L. The changes in the slope of T1 (2H) = ƒ ( T ) can be interpreted as due to the effect of concentration changes on Ty and simultaneously strong overlaping of 2H NMR signals from coexisting phases. In the two-phase region, ca. 2°C above TC, L two D2O signals with very strong temperature evolution have been detected. Similar doubling of 2,6-lutidine 1H NMR signals has been observed already at T - TC, L ≦ 1 °C. It is shown that the two signals arise from the nuclei in two coexisting phases; they are not due to pecularities of hydrogen bond. The difference between chemical shifts of both D2O signals δ’ - δ” possess the property of an order parameter, i.e. δ’ - δ” ~ εβ with β = 0.336±0.030
Determination of the Ring-Inversion Barrier in γ-Thiobutyrolactone by Microwave Fourier Transform Spectroscopy
Authors: Harder H. , Lesarrif A. G. , Alonso J. L. , Dreizler H. , López J. C.
Published: February 2015

The microwave spectrum of γ-thiobutyrolactone has been reinvestigated using microwave Fourier transform spectroscopy. The μc rotation inversion transitions have been found to be splitted for the first excited state of the vibration at ~ 250 cm-1 . An inversion splitting of 0.014 MHz has been measured directly from these transitions. These splittings indicate that the vibration is related to a double minimum potential function describing two ring-twisted conformations connected by inversion. A one-dimensional reduced potential function has been derived for this vibration and gives a barrier to ring inversion of 1380± 350 cm-1.
The Kinetics and Formation of Small Carbon Clusters in an Argon Matrix
Authors: Szczepanski Jan , Pellow Robert , Vala Martin
Published: February 2015

Pure carbon clusters, formed by Nd/YAG laser ablation of graphite, have been trapped in an argon matrix at 12 K. The temperature dependence of the prominent infrared absorption bands attributable to C3 , C5 , C6 , and C9 clusters has been investigated between 12 K and 38 K. The former two are observed to decay and the latter two to grow with increased matrix annealing. A new kinetic model based on solid state diffusion theory and involving thermally activated diffusion and aggregation is introduced. All possible pairwise interactions of the linear carbon clusters from C1 to C10 are included in the model. The coupled differential equations are solved numerically and provide a reasonable fit to the experimental temperature profiles of the known clusters. Predictions emerge from the fit for the unknown matrix infrared frequencies for the C7 cluster. On the basis of the predicted concentration invariance with temperature for C7 , the infrared bands at 2128 cm-1 and 1894 cm-1 are ascribed to this linear cluster. This attribution supports the recent assignment of the gaseous 2138 cm-1 band to linear C7 .
Scaled Quantum Mechanical (SQM) Force Field Calculations of the Hexathiometadiphosphate Anion P2S2-
6
Authors: Ystenes Martin , Brockner Wolfgang , Menzel Frank
Published: February 2015

By ab initio quantum mechanical calculations on P2S2-
6 its equilibrium energy, geometry and vibrational frequencies along with their PED values have been obtained. The basis sets STO-5G, 6-31G, STO-5G* and 6-31G* were employed, and force field calculations were carried out at the STO-5G and the STO-5G* levels. The calculations show that the assignment for some bands between 180 and 260 cm -1 should be corrected. Two scaling factors were needed to fit the calculated frequencies with the observed frequencies within a deviation of less then 20 cm -1 for all vibrations, with the exception of v6(B1g). The calculated frequency of this vibration is very dependent on the polarization functions, and use of STO-2G for the 3d-orbitals corrects most of the deviation. STO-5G* and 6-31G* both give a good description of the geometry of the title ion, although STO-5G* yields a 0.04 Å too short terminal P - S distance.
Notizen: Comment on the Osipov-Terentjev Calculation of the Viscosity of Liquid Crystals
Authors: Stepanov V. I.
Published: February 2015

The calculation of the viscosity of liquid crystals based on the rotational diffusion approximation recently reported by Osipov and Terentjev [1 a] is critically examined. It is shown that the main result of their treatment - the evaluation of the activational exponent - arises from the neglect of the second derivative of the distribution function with respect to the azimuthal angle in the Fokker-Planck equation. The correct asymptotic formula for the rotational viscosity coefficient is derived.
Surface Tension Around Eutectic Compositions of Molten Alkali Carbonate Mixtures
Authors: Igarashi Kazuo , Tajiri Koji , Asashina Tadashi , Kosaka Mineo , Iwadate Yasuhiko , Mochinaga Junichi
Published: February 2015

The surface tension around the eutectic composition of molten binary and ternary mixtures composed of Li2CO3 with Na2CO3 and/or K2 CO3 has been measured by the maximum bubble pressure method. The surface tensions of all the three systems were represented as functions of temperature
ESR Spectra of Para-Substituted Alkyl- and Alkenylbenzene Radical Cations in Halocarbon Matrices
Authors: Kubozono Yoshihiro , Ata Masafumi , Suzuki Yasunobu , Gondo Yasuhiko , Shiotani Masaru
Published: February 2015

The ESR spectra of several para-substituted alkyl- and alkenylbenzene radical cations generated by 60Co γ-ray irradiation in halocarbon matrices at 77 K have been studied with the aid of semiempirical MO calculations. It has been found that the ethyl conformation of 1,4-diethylbenzene radical cation (1,4-DEB+. ) in CCl2FCClF2 is largely different from that in CCl3CF3. Further the ethyl and n-propyl groups in 4-ethyltoluene and 4-n-propyltoluene radical cations in CCl2FCClF2 take different conformations from that of 1,4-DEB +.. The conformations of the alkylbenzene radical cations depend strongly both on the matrices and on the substituent groups. A peculiar radiolytical reaction of 1,4-diisopropylbenzene to a deprotonation-type neutral radical in CCl2FCClF2 has been found, similarly to the case of photolysis.
The PN Method in the Kinetic Theory of Gases
Authors: Kügerl Georg , Schürrer Ferdinand
Published: February 2015

An expansion of the velocity distribution function in a series of spherical harmonics is used to transform the nonlinear Boltzmann equation into a system of moment equations. The close connection between the moment equations of zeroth and first order with the transport equations for mass, momentum and energy is pointed out. By comparing the order of magnitude of the various moments it is shown that the P2 approximation is adequate for systems with small mean free path. Simplifications of the collision terms of the moment equations are discussed, where attention is payed to the conservation laws and the H theorem
Radiolysis of Aqueous Ethanol in the Presence of CO
Authors: Park Hyoung-Ryun , Getoff Nikola
Published: February 2015

First, the following rate constants (in dm3 mol-1 s-1 ) were reported: k(eaq
-+ C2H5OH) = (1.2 ± 0.3) x 103, k(H + C2H5OH) = (2.8 ± 0.2) x 107 and k(OH + C 2H5OH) = (1.85 + 0.1) x 109 The major radiolytic products resulting from aqueous 10-2, 1 and 10 mol dm-3 ethanol were studied in the absence and presence of CO as a function of dose at pH 2 and 7. Probable reaction mechanisms are presented
Intramolecular and Liquid Structures of Tetramethylurea Studied by Means of X-Ray Diffraction
Authors: Radnai T. , Ohtaki H.
Published: February 2015

The intramolecular and liquid structures of tetramethylurea (TMU) were investigated by the liquid x-ray diffraction method. It is confirmed that in the liquid state the four methyl groups are out of the plane which is constructed by the O, C, and the two N atoms, the molecular structure being similar to what had been found in the gas phase. All structural parameters are in good agreement with those of TMU determined in the gas phase and with those of amide derivatives in the liquid phase. The liquid is characterized by a random distribution of molecules as predominant, but a weak molecular ordering characterized by approximately two intermolecular nonbonding Me ··· O distances at 340 pm is proposed
Oxygen Diffusion in YBa2Cu3O7–δ Studied via 133Ba(EC)133Cs Nuclear Quadrupole Interaction
Authors: Tröger W. , Butz T.
Published: February 2015

The oxygen diffusion in YBa2Cu3O7-δ was studied between 300 K and 1273 K in flowing oxygen by monitoring the 133Ba(EC)133 Cs nuclear quadrupole interaction by time differential perturbed angular correlation. The data are analyzed in a model of two different nearest neighbour oxygen configurations and yield hopping rates, the energy barrier and the difference in free enthalpy between both states. In addition, we studied the reduced system YBa2Cu3O6 +ε.
Nucleus-Carrier Interactions in the Group V Semimetals: Dependence on Temperature and Pressure
Authors: Keartland J. M. , Goudemond I. P. , Fölscher G. C. K. , Hoch M. J. R.
Published: February 2015

A review is given of pulsed NQR spin-lattice relaxation measurements on the rhombohedral semimetals, arsenic (As) and antimony (Sb). The nuclear spin-lattice relaxation time T1 has been measured in the temperature range 100 mK-600 K. The data follow the Korringa relation at low temperatures, but deviations from this relation are found as the temperature is increased. The results are quantitatively explained by considering interactions of the nuclei with the carriers at the Fermi surface. Above the Debye temperature (θD) the data may be understood by including a two phonon process in the analysis. The relaxation data for As and Sb are found to scale with θD. T1 has been measured for As at 295 K in the pressure range 0 - 10 kbar. The results are discussed in terms of changes in the Fermi surface parameters.
The Nuclear Quadrupole Interaction of 199mHg-Cysteine and 199mHg-tert-butyl-mercaptide
Authors: Butz T. , Tröger W. , Pöhlmann Th. , Nuyken O.
Published: February 2015

The nuclear quadrupole interaction of 199mHg in Hg-cysteine and Hg-tert-butyl mercaptide was determined at room temperature by perturbed angular correlations. The dramatic difference in the interaction strength between both compounds is a result of the two-fold and four-fold sulfur coordination, respectively. Moreover, we compared the preparation of Hg-cysteine using a Hg: cysteine ratio of 1:2 and using carrier-free 199mHg from ISOLDE/CERN and obtained identical results.
Electron Effects of Adduct Formation by some Metal Halides
Authors: Kravchenko E. A , Burtzev M. Yu.
Published: February 2015

The results of NQR studies on electron density redistribution due to formation of adducts of various types of metal halides are reviewed and their consistency with X-ray data is discussed
The Nuclear Quadrupole Moments of the 20 First Elements: High-Precision Calculations on Atoms and Small Molecules
Authors: Pyykkö Pekka
Published: February 2015

The available values of the nuclear quadrupole moments for the elements H - Ca are reviewed and related to recent advances in numerical methods in quantum chemistry. For Li the quantum chemical and nuclear Coulomb scattering values now agree. For Mg, also the muonic result agrees with them. For Na and Al, the new, accurate atomic values deviate from the earlier muonic values
Ab initio Calculations of the Electric Field Gradients in Solids in Relation to the Charge Distribution
Authors: Schwarz Karlheinz , Blaha Peter
Published: February 2015

A first principles method for the computation of electric field gradients (EFGs) is illustrated for various solids. This scheme is based on self-consistent energy band-structure calculations by the full potential linearized augmented plan wave (FLAPW) method which provides the electronic charge density including all polarization effects. By numerically solving Poisson's equation we obtain the Coulomb potential in a form which allows to compute the EFG directly. Our method is demonstrated for insulators (Cu2O), metals (hcp-Zn), supercondutors (YBa2Cu3O7 ) and molecular crystals (Cl2, Br2 , I2).
Milli-Kelvin NQR: A Study of the Praseodymium Trihalides
Authors: Armstrong Robin L. , Su Sunyu
Published: February 2015

Milli - Kelvin NQR experiments are often essential for the study of pseudo one-dimensional materials. A brief overview of the special technical consideration for carrying out NQR measurements in a dilution refrigerator is given. Recent halide quadrupole resonance experiments on the pseudo one-dimensional XY crystals PrCl3 and PrBr3 are reviewed including the measurement and interpretation of frequencies, and spin-lattice relaxation times.
Chlorine Nuclear Spin-Spin Relaxation Mechanism in Mg(H2O)6SnCl6 as Studied by NQR and NMR Techniques
Authors: Horiuchi Keizo , Nakamura Daiyu
Published: February 2015

The 35Cl NQR spin-lattice relaxation time T1Q, spin-spin-relaxation time T2Q, and 1H NMR spin-lattice relaxation time in the rotating frame T1Q in Mg(H2O) 6SnCl6 were measured as functions of temperature. Above room temperature T2Q increased rapidly with increasing temperature, which can be explained by fluctuations of the local magnetic field at the chlorine nuclei due to cationic motions. From the T1Q experiments, these motions are found to be attributable to uniaxial and overall reorientations of [Mg(H2O)6 ] 2 + ions with activation energies of 95 and 116 kJ mol - 1 , respectively. Above ca. 350 K, T1Q decreased rapidly with increasing temperature, which indicates a reorientational motion of [SnCl6] 2 - ions with an activation energy of 115 kJ mol -1 .
Reorientation of the CCl3 Group in Chloral 4-Chlorobenzylhemiacetal. A Pulsed 35Cl NQR and X-ray Study
Authors: Hashimoto Masao , Isono Takahiro , Yomesaka Noriko , Niki Haruo , Kyan Hiroshi , Hamagawa Takeshi
Published: February 2015

The crystal structure of the title compound was determined at 291 K : monoclinic, space group C5
2h-P21/n, Z = 4, a = 1693.2(1), b = 579.3(1), c = 1232.5(1) pm, and ß = 107.21 (1)°, R = 0.0415. A sharp decrease of of Cl NQR found at T ≳ 270 K for the CCl3 group is attributed to the reorientation of the group over a potential barrier of ca. 50 kJ/mol. Intermolecular interactions between the CCl3 and the neighboring atoms seem to dominate the magnitude of the potential barrier. T1
-1 of the 35Cl NQR of the Cl atom on the benzene ring obeyed the T2 law well in the range 80 ≲ T/K ≲ 270, while at T ≳ 280 K it deviated from the T2 law.
Quadrupole Hyperfine Structure in the Rotational Spectra of Sulfur Dichloride
Authors: Merke Ilona , Dreizler Helmut
Published: February 2015

The nuclear quadrupole coupling of [35Cl,35Cl]- and [35Cl,Cl]-sulfur dichloride was investigated using waveguide microwave Fourier transform (MWFT) spectroscopy. The analysis was performed with direct diagonalization of the Hamilton matrix. Due to some measured transitions with near degeneracy it was possible to determine the off diagonal elements χab of the quadrupole coupling tensor with high accuracy.

S35Cl2: χ aa (35Cl1) = χaa(35Cl2) = -38.671(11) MHz, χcc(35Cl1) = χcc(35Cl2) = 47.7945(66) MHz, χab(35Cl1) = -χab( Cl2) = ± 53.76(23) MHz.

S35Cl36Cl: χaa(35Cl) = -37.756(13) MHz, χcc(35Cl) = 47.7915(75) MHz, χab(35Cl) = ± 54.018(83) MHz, χ aa(35Cl) = -31.217(13) MHz, χcc (37Cl) = 37.6759(66) MHz,

χab ( 37 Cl ) = + 42.285(98) MHz.

We also determined the quadrupole coupling constants in their principal axes system. In comparison with the restructure the z-axis of the coupling tensor was found to be tilted 1.3° out of the S - Cl bond axis
Nuclear Quadrupole Coupling in the Rotational Spectrum of Thionyl Chloride
Authors: Merke Ilona , Dreizler Helmut
Published: February 2015

We report on the analysis of the chlorine quadrupole hyperfine structure of thionyl chloride, S035Cl37 Cl, observed with a molecular beam microwave Fourier transform spectrometer
Debye-Waller Type Expressions for the Nuclear Elastic Form Factors at Small Momentum Transfers
Authors: Grypeos M. E. , Lalazissis G. A. , Massen S. E. , Panos C. P.
Published: February 2015

The problem of estimating the nuclear elastic form factors in Born approximation is discussed in the region of small momentum transfers q. It is shown that approximate expressions of the Debye-Waller type are suitable for estimates of these form-factors in the oscillator shell model for sufficiently small q and compare favorably with other simple expressions.
Further Study of Intersectorial Isotope Fractionation in Quartz
Authors: Klemm A. , Banerjee A. , Hoernes S
Published: February 2015

It is shown that the intersectorial boundary in crystals must be straight if the intersectorial isotope effect is to be measured in the presence of isotopical mantle zoning.
Surface Energy for Nematic Liquid Crystals: A New Point of View
Authors: Alexe-Ionescu A. L. , Barberi R. , Barbero G. , Beica T. , Moldovan R.
Published: February 2015

The surface energy of nematic liquid crystals is deduced from a phenomenological point of view. The idea of an easy surface tensor order parameter is proposed. An expression similar to a Landau expansion for the free energy of a system characterized by two order parameters is deduced and analysed. An interpretation similar to the one usually accepted for magnetic materials is given. The possibility of surface transitions induced by temperature is discussed.
Dipole Moment and High Resolution Rotational Spectrum of Fluorocyanoacetylene, FCCCN
Authors: Krüger Michael , Merke Ilona , Dreizler Helmut
Published: February 2015

The title molecule was produced in a dc discharge from pentafluoro benzonitrile, C6F5CN. The dipole moment of fluorocyanoacetylene was found to be 3.05(15) D from the Stark effect. The 14N nuclear quadrupole coupling constant ϰzz = - 4.2513 (47) MHz was determined from high resolution rotational spectra obtained with a pulsed nozzle molecular-beam microwave Fourier transform spectrometer.
Luminescence Spectra of Mn2+ Doped in Langbeinites
Authors: Böttjer T. , Stockhausen M.
Published: February 2015

Luminescence data for 6 manganese doped langbeinites, A2
+B2
2+ (SO4)3, are reported. They are consistent with octahedral symmetry of the impurity center (substitutional in B site), although for the host lattice the B site is known to show three-fold axial (distorted octahedral) symmetry only. In accordance with previous conclusions from EPR data the luminescence parameters indicate structural relaxation in comparison to undoped langbeinites.
Phase Transition in Cesium Enneabromodibismuthate(III), Cs3Bi2Br9 ; an 81Br and 209Bi NQR Study
Authors: Terao Hiromitsu , Ishihara Hideta , Okuda Tsutomu , Yamada Koji , Weiss Alarich
Published: February 2015

The 81Br and 209Bi NQR spectra of Cs3Bi2Br9 have been studied over a wide temperature range (81Br-NQR: 77 ≤ T/K ≤ 383; 209Bi-NQR: 77 ≤ T/K ≤ 310). Therefrom a phase transition in the compounds is found which is probably of second order.
Structure of Supercooled Aqueous Zinc(II) Bromide Solutions by Raman and X-Ray Scattering Methods
Authors: Takamuku Toshiyuki , Yoshikai Kazumasa , Yamaguchi Toshio , Wakita Hisanobu
Published: February 2015

The structure of aqueous zinc(II) bromide solutions with [H2O/[ZnBr2] molar ratios 5 and 10 in the supercooled state and at ambient temperature has been investigated by Raman spectroscopy and X-ray scattering. Raman spectra of glassy solutions have also been measured for comparison. The Raman and X-ray data suggest that tetrabromo and hexaaqua zinc(II) complexes are favoured in the supercooled and glassy state, while dibromo- and tribromozinc(II) complexes are formed as main species in the solutions at ambient temperature. Probably the reactions

and

occur in the supercooled and glassy solutions. These equilibrium shifts are discussed.
The Microwave Spectra and Nitrogen Quadrupole Coupling Constants of Cyano- and Isocyano-pentafluorobenzene
Authors: Krüger Michael , Dreizler Helmut
Published: February 2015

The microwave spectra of cyano-pentafluorobenzene, C6F5CN, and isocyano-pentafluorobenzene, C6F5NC , have been assigned by molecular beam microwave Fourier transform spectroscopy. The 14N nuclear quadrupole coupling constants have been determined for both isomers
Conformational Aspects of Substituents in Enamines. X-Ray Structure Analyses and Quantum Chemical Calculations
Authors: Raabe Gerhard , Karl Wolfgang , Enders Dieter , Fleischhauer Jörg
Published: February 2015

X-ray structure determination of the enamine (Z)-4-(6'-t-butoxycarbonyl-2',2'-dimethyl-5'-phenyl- 3'-hexen-3'-yl)morpholine (1) reveals that certain bulky groups may enforce a relative orientation of the molecular subunits without conjugative interaction between the nitrogen lone pair and the olefinic double bond. According to the results of quantum chemical ab initio calculations the experimentally found arrangement would be the least favourable one in the absence of such substituents. A careful analysis of the molecular structure of 1 shows that this unusual arrangement is due to the presence of both, the a- and the ß-substituent.

In (E)-4-(3'-t-butoxycarbonylmethyl-1'-phenyl-1'-penten-1'-yl)morpholine (2) rather the nitrogen lone pair than the phenyl n system is in conjugation with the olefinic double bound. The results of ab initio calculations on model compounds show that conjugation of the double bond with the nitrogen lone pair is by 2 - 6 kcal/mol more favourable than conjugative interaction between the phenyl group and the C = C bond. Closer examination of the molecular structure of 2, however, led to the conclusion that it is predominantly the ß-substituent which forces the phenyl ring in a position where conjugation with the enamine double bond is not possible
A Photophysical Study of Tri-chromophoric Systems Containing Two Naphthalene Moieties: Intramolecular Excimer Fluorescence, Energy Transfer, Phosphorescence, and Delayed Fluorescence
Authors: Gundermann Karl-Dietrich , Romahn Elke , Zander Maximilian
Published: February 2015

Photophysical properties of 9,10-di[(l-naphthyl)-methyl]-9,10-dihydro-9,10-phenanthrenediol (1), 9,10-di(l-naphthyl)phenanthrene (2), 9,10-di(2-naphthyl) phenanthrene (3), 10,10-di(1 -naphthyI)- 9,10-dihydro-9-phenanthrone (5 a) and 10,10-di(2-naphthyl)-9,10-dihydro-9-phenanthrone (5 b) have been studied. In contrast to l,4-di(l-naphthyl)butane compound 1 shows strong (intramolecular) excimer fluorescence in dilute solution at room temperature. As a result of intramolecular triplettriplet energy transfer the phosphorescence of 2, 3, 5 a and 5 b stems from the naphthalene moieties. The increase (compared to naphthalene) of the rate constant of the radiative deactivation of the lowest triplet state is probably due in the case of 2 and 3 to the non-planarity of the molecules, which is expected to increase spin-orbit coupling, while in compounds 5 a and 5 b intramolecular chargetransfer interaction between the carbonyl group and the naphthalene moieties may be responsible for this effect. Delayed fluorescence (from the phenanthrene moiety) of 2 has been observed in fluid solution at room temperature, and an excitation mechanism is proposed
Luminescence Spectra of the Mixed Chloro-Bromo-Technetates(IV), [TeClnBr6-n]2-n=1-5
Authors: Wendt A. , Preetz W.
Published: February 2015

The Γ7(2T2t) Γ8(4A2g) luminescence spectra of mixed Cs2[TcClnBr6-n, n= 1-5, in various host crystals have been measured between 14 000 and 12 800 cm-1 at 10 K. For the first time host lattices have been doped with purely isolated chloro-bromo-technetates(IV), including the geometrical isomers with n = 2, 3, 4. The assignments of the electronic transitions and their extensive vibronic structure are discussed.