bluuebunny/crossref_metadata_2025 huggingface dataset:
On the High Ionic Conductivity of Solid Solutions of Lithium Sulphate in Hexagonal Sodium Sulphate Na2SÒ4(I)
Authors: Lundén Arnold , Nilsson Leif
Published: February 2015

Solid solutions of Li2SO4 in the high-temperature phase Na2SO4 (I) have a much higher conductivity than expected. Diffusion and electromigration experiments show that both Li+ and Na+ ions are very mobile. It is concluded that the Li+ ions go into interstitial positions of the type (1/2,0,0), while vacancies are created in the Na+ lattice
Model Calculations of the Structure of Ni-Nb Metallic Glasses
Authors: Lamparter P.
Published: February 2015

The partial pair correlation functions of amorphous NixNb100-x alloys (x = 40, 50, 56, and 63) were simulated by computer modelling. A Cluster Relaxation procedure yielded reasonable agree­ ment with the experimental functions when non-additive pair potentials with preference for Ni-Nb atomic pairs were applied. With the use of the Reverse Monte Carlo method perfect agreement could be achieved. The impact of the chemical effect on the short range order is discussed by comparison with a statistical reference cluster. The analysis of the model clusters showed that the chemical short range order effect in amorphous Ni-Nb alloys, increasing with the Ni concentration, does not in­ volve specific stereochemical atomic arrangements. There is no correspondence to the short range order in crystalline Ni3Nb. The structure of Ni-Nb metallic glasses can be described as a polytetra-hedral packing with preferred hetero-coordination.
Thermodynamic Analysis of Isotope Effects on Triple Points and/or Melting Temperatures
Authors: Van Hook W. Alexander
Published: February 2015

Àbstract

Available literature information on triple point or melting point isotope effects (and related physical properties) is subjected to thermodynamic analysis and consistency checks. New values for the melting point isotope effects for C6H6/CgD6 and c-C6H12/c-C6D12 are reported. 6Li/7Li melting point isotope effects reported recently by Hidaka and Lunden (Z. Naturforsch. 49 a, 475 (1994)) for various inorganic salts are questioned
The High-Frequency Rotational Spectrum of 1,1 -Dichloroethylene
Authors: Kisiel Z. , Pszczółkowski L.
Published: February 2015

The b-type rotational spectrum of 1,1-dichloroethylene was investigated up to 450 GHz and was found to be dominated by type-II R-type bands. All constants in the sextic Hamiltonian for the ground states of the common isotopic species and of the 37C1 isotopomer were determined from measurements on transitions with J up to 95. Quartic and sextic planarity defects were evaluated and are compared and discussed with those for several recently investigated planar molecules
Rotational Tunnelling in Binary Tetramethylmetal Mixtures
Authors: Prager Michael , Zhang Da , Weiss Al.
Published: February 2015

Mixed PbcSn1-c(CH3)4 samples with c = 0.0, 0.1, 0.2,0.25, 0.48, 0.5, 0.75,0.85, and 1.0 and mixed [Pb(CH3)4](.[Sn(CD3)4]1-c. samples with c = 0.02 and 0.09 were investigated by high resolution inelastic neutron scattering. Rotational tunnelling transitions are observed for energy transfers hω<100 μeV. The global features are interpreted in a single particle model. A strong matrix effect of the Pb component is attributed to changes of potential symmetry. Effects beyond the expectation of the single particle description are found
Critical Curves and Phase Equilibria of Binary Methanol-Systems for High Pressures and Temperatures
Authors: Neichel M. , Franck E.U.
Published: February 2015

The critical curves of binary systems of methanol combined with CH4, N2, H2, CO and CO2 have been determined experimentally up to 100 MPa and higher by Brunner. In the present work a rational equation of state of the perturbation type with a repulsion and an attraction term has been applied to reproduce these critical curves up to high pressures. A square well potential for intermolecular interaction is used. With pairwise combination rules for these potentials three adjustable parameters are needed. Values for these parameters, obtained from the fitting of the critical curves are used to calculate isotherms of the two-phase high pressure equilibrium surfaces for the four systems of methanol combined with CH4, N2, H2, and CO. Three of these have not yet been investigated experimentally. It is suggested to use this procedure for predictions of the extent of three-dimensional two-phase regions in temperature-pressure-composition spaces
Structural Analysis of a Cs + O Coadsorption Phase on a Ru(0001) Surface
Authors: Gierer M. , Bludau H. , Over H. , Ertl G.
Published: February 2015

The adsorption of oxygen onto a Ru(0001)-(2 x 2)-Cs phase with coverage ΘCs = 0.25 gives rise to the formation of a Ru(0001)-(2√3 x 2√3)R30°-3Cs-20 coadsorption structure with three cesium and two oxygen adatoms in the unit cell. A low-energy electron-diffraction (LEED) analysis reveals that oxygen is located in threefold hollow sites on the Ru surface while the Cs atoms remain near on-top sites; this site was also found in the pure Ru(0001)-(2 x 2)-Cs phase. The oxygen-Ru bond length of (2.14 ± 0.05) Å is longer by 0.11 A than in the Ru(0001)-(2x2)-0 phase, indicating that the Ru-O bond is weakened in the presence of coadsorbed Cs. The Cs hard sphere radius of (1.75 ± 0.07) Å is close to the ionic Pauling radius of 1.69 Å
Thermodynamics and Hysteresis for Hydrogen Solution and Hydride Formation in Pd-Ni Alloys
Authors: Flanagan Ted B. , Noh H.
Published: February 2015

Pd and its fee substitutional alloys which form hydride phases exhibit hysteresis. If Pd-Ni alloys have been hydrided and then dehydrided a number of times at a moderate temperature, the hysteresis is reduced. The reduction of hysteresis increases with increase of XNi to 0.15 and, if the XNi = 0.15 alloy is hydrided and dehydrided (298 K) a number of times, hysteresis disappears. Hydrogen isotherms have been measured for annealed Pd-Ni alloys from XNi = 0.05 to 0.25 (273 K). These show that the width of the plateau region decreases from XNi = 0 to ≈ 0.15 and then increases again. This trend is not apparent from previous isotherm measurements but it is consistent with the x-ray results available in the literature. Thermodynamic parameters for hydrogen absorption/desorption have been measured in the dilute phase and in the plateau region
Ion-Ion De-Association and Association of Strong Electrolytes at High Dilution from Nuclear Magnetic Relaxation Measurements
Authors: Detscher E. , Hertz H. G. , Holz M. , Mao Xi-an
Published: February 2015

Proton magnetic relaxation rates in the system N(CH)3)4Br/NiBr2/D2O, N(CH3)4Br/MnBr2/ D2O, Ni(00CCH3)2/D2O and Mn(00CCH3)2/D2O have been measured as a function of the solute concentration in the range 0.002 < c* ⪍ 1 m. Division by the concentration c* and by a quantity characterizing the ionic motion yields the association parameter (4-parameter). A decreases and increases with decreasing concentration for the systems involving cation-cation and cation-anion interaction, respectively. The relaxation rates of 35C1-, 133Cs+ , and 25Mg++ in diamagnetic aqueous solutions have also been measured down to high dilution. Here as well in most cases we have found an increase of the A-parameter with decreasing salt concentration, indicating ion-ion association at high dilution. A comparison with the results of the Debye-Hückel theory is given; there is qualitative agreement. Our experimental results for 35C1- generally do not support theoretical considerations in the literature, where a Cl--Cl- association was postulated
Cluster Formation in Liquid Lithium Niobate A Small Angle X-ray Scattering Investigation
Authors: Andonov P. , Kimura S. , Kobayashi A.
Published: February 2015

T

Structural analysis of the clustering phenomenon in the LiNbO3 melt was carried out by means of small-angle X-ray scattering using synchrotron radiation in the range of momentum transfer 0.2 nm-1 ≤ k ≤ 14.0 nm-1. Microclusters were present in the melt throughout the entire explored temperature-domain from 1673 K to 1513 K which includes undercooling (melting point 1526 K). The radius of gyration, size, shape and distance of particles were determined. Chains of few NbO6 octahedra and small blocks constituted by two layers of four corner-shared octahedra, interlocked by a lithium atom, could be good models for the microclusters in a large temperature-domain. By lowering the temperature, the particle size increased. Below 1553 K, probable macroclusters would be correlated to the rapid increase of the viscosity. Using the viscosity data and previously published and the present SAXS results, it was possible to evaluate the volume of the clusters. Near the freezing point about a quarter of the volume would be occupied by clusters.
Microscopic Stress Tensor of Nematic Liquid Crystal Binary Mixtures
Authors: Chrzanowska Agnieszka , Jochym Pawel T.
Published: February 2015

A microscopic stress tensor for the binary nematic mixture of anisotropic molecules is presented. Its simple additive character is beneficial for hydrodynamics studies. We pay attention to mixtures of disc and rodlike molecules which may exhibit interesting hydrodynamic properties.
On the Interaction of the S–Ion with H2 at low Collision Energies
Authors: Gritli Hager , Chambaud Gilberte , Rosmus Pavel
Published: February 2015

Potential energy functions have been calculated for the reactions S- (2P) + H2 → HS + H- and S-(2P) + H2 → HS- + H for low collision energies and collinear geometries. Unlike in the O- + H2 system, only very flat polarisation minima in the structures S- . . . H2 and SH...H- have been found. They are not deep enough to support the formation of a complex in the detachment, in the reactive detachment and in the reactive charge transfer processes of the S- + H2 collision system.
Painlevé Analysis and Symbolic Computation for a Nonlinear Schrödinger Equation with Dissipative Perturbations
Authors: Tian Bo , Gao Yi-Tian
Published: February 2015

The nonlinear Schrödinger equations with small dissipative perturbations are of current importance in modeling weakly nonlinear dispersive media with dissipation. In this paper, the Painlevé formulation with symbolic computation is presented for one of those equations. An auto-Bäcklund transformation and some exact solutions are explicitly constructed
Generalized tanh Method and Four Families of Soliton-Like Solutions for a Generalized Shallow Water Wave Equation
Authors: Tian Bo , Gao Yi-Tian
Published: February 2015

We report that a generalized tanh method with symbolic computation leads to 4 families of soliton-like solutions for the Jimbo-Miwa's (3 + 1)-dimensional generalized shallow water wave equation.
Short-Range Order in KPO3 Glass Studied by Neutron and X-Ray Diffraction
Authors: Hoppe Uwe , Walter Günter , Stachel Dörte , Hannon Alex C.
Published: February 2015

The short-range order of KPO3 glass has been studied by diffraction methods in order to make evident the different behaviour of the P-O bonds within the PO4 tetrahedron. The oxygen sites are devided into bridging and terminal (non-bridging) oxygen sites, corresponding to two P-O bond lengths, the difference of which amounts to 14.5 pm. Previous conclusions about the changes of the P-O bond lengths under the influence of modifier cations of different electric field strength are corroborated. The K-O environments reveal two apparently different distances rKO with equal contributions to the total K-O coordination number of about 6.7. To explain this phenomenon, the K+ cations are suggested to be located in non-spherical cavities
Heat Capacities of Thermally Treated Na2O-3B2O3 Glasses Above and Below Tg
Authors: Mustarelli Piercarlo , Tomasi Corrado
Published: February 2015

Various contributions have been obtained from the heat capacities of "as quenched" and annealed Na2O - 3B2O3 glasses. It is shown that the enthalpic release gives a major contribution to the DSC curves obtained by reheating quenched glasses. Different relaxation processes are followed by comparing DSC scans of quenched and annealed samples in the vitreous state and around the glass transition temperature, Tg. As a function of the annealing time at T = T8 - 30 °C, the specific heats at room temperature initially increase, due to the decrease of the exothermic contribution from quenched-in defects, which are absent in a fully annealed glass; over a month-long time scale these heat capacities drop, due to a partial ordering, which decreases the configurational contribution. Such a decrease is related with the "overshoot" which occurs above and which attains a limiting value ΔHg ≅ 14 J mol-1 in a matter of days. The heat capacities above Tg relax towards a value of CP of ≅ 2.3 J mol-1 K-1 after a few days of annealing, which is intermediate between the anomalously low CP (∼ 1.8 J mol-1 K-1 ) of a fast quenched (∼103 K min-1 ) and that ( ∼ 2 . 9 J mol-1 K-1 ) of a sample annealed for one hour. These phenomena point to complex relationships among enthalpic relaxation, entropic relaxation and temperature in these glasses
Internal Cation Mobilities in the Molten Binary System (Ag, Tl)NO3
Authors: Chou Pao-hwa , Okada Isao
Published: February 2015

Internal mobility ratios in the molten binary system (Ag, Tl)NO3 have been measured by Klemm's countercurrent electromigration method. In the usual way the internal cation mobilities b have been calculated from these data and those available on the densities and conductivities. In the investigated region of temperature and composition bAg is greater than bTl
EPR Study of Cr5+ and Cu2+ in Some Zeolites Introduced by Solid- and Liquid-State Reactions
Authors: Köksal Fevzi , Ucun Fatih , Kartal İbrahim
Published: February 2015

This study reports on the EPR of Cr5+ and Cu2+ ions, introduced by solid- and liquid-state reactions with the synthetic zeolites 3A, 4A and 5A, and the natural zeolite clinoptilolite. Cr3+ was oxidized to Cr5+ in the samples, the coordination around Cr5+ being square pyramidal. Super-hyperfine (shf) interaction of Cr5+ with 27Al nucleus was observed in both solid-and liquid-state-introduced 5A zeolite, whereas this shf could not be observed for the solid-state introduced 4A zeolite. The liquid-state Cr-introduced 4A zeolite needed a heat treatment at 473 K for ½ h for the appearance of shfs. Furthermore, it has been found that the coordination structure around the Cu2+ is square pyramidal in solid-state introduced samples, whereas it is octahedral in the liquid-state introduced ones.
Analysis of Torsion in a Three-Top Molecule. Torsional Barrier and Moment of Inertia of Trimethyl Ethynyl Germane
Authors: Voges K. , Gripp J. , Hartwig H. , Dreizler H.
Published: February 2015

Internal rotation effects for a large number of molecules containing one or two symmetric internal rotors have been investigated using microwave spectroscopy. The high resolution of molecular beam Fourier transform microwave spectroscopy revealed now the internal rotation fine structure in the rotational spectrum of trimethyl ethynyl germane, (CH3)3GeC=CH. After assigning the rotational transition J = 1 → 0 in the vibrational and torsional ground state to the symmetry species of the molecular symmetry group G162 , the torsional barrier V3 and the rotational constant B0 could be determined to (4.5±0.2) kJ/mol and (1823.370±0.010) MHz, respectively.
On Anyonic Variables and Fractional Supersymmetry
Authors: Ahmed E.
Published: February 2015

A modified definition for anyonic variables is given. They are used to construct a representation for superspace of fractional supersymmetry in two dimensions. An extension to higher dimension is presented.
ESR Spectrum and Magnetic Behavior of Copper(II) Sebacate
Authors: Lezama L. , Rojo T. , Baran E. J. , Torre M. H.
Published: February 2015

The magnetic susceptibility of copper(II) sebacate, measured between 5 and 400 K, confirms the presence of strongly coupled Cu-Cu pairs. The ESR spectrum, obtained with a polycrystalline sample, shows an important rhombic anisotropy and supports a dx2-y2 ground-state.
Dielectric Relaxation Studies of 4-n-Alkyloxy-4’-Cyanobiphenyls (nOCB, n= 5÷8)
Authors: Urban S. , Gestblom B. , Kresse H. , Dąbrowski R.
Published: February 2015

The results of dielectric relaxation studies of series of four n-alkyloxy cyanobiphenyl (nOCB) compounds with n ranging from 5 to 8 are presented. The complex dielectric permittivity, ε*(ω) - ε’(ω) - i ε’’(ω), was measured in the frequency range 1 kHz - 3 GHz, with the use of an impedance analyzer and a time domain spectroscopy (TDS) set-up. The relaxation times: longitudinal τ|| in the nematic and smectic A phase (80CB), transverse τ⊥ in the nematic phase, and τis in the isotropic phase, were obtained as functions of the temperature. This allowed the calculation of activation barriers for different molecular relaxation processes occurring in particular phases. More-over, the retardation factors g|| and g⊥ and the nematic potential q according to two theoretical models were calculated. The analysis of q(T) and its relation to the order parameter S is done taking into account the results of NMR studies of the compounds under consideration. Finally, the dependencies of the obtained quantities on the number of carbon atoms in the alkyloxy chains are analyzed.
Analysis of the FTIR Bands v11 and v8 of 1,1-difluoroethylene with Rotational Background Information on Excited States
Authors: Stiefvater Otto L.
Published: February 2015

Much earlier work on the analysis of the fundamental infrared bands v11 and v8 of 1,1-difluo-roethylene has been resumed and extended.

The Q-branch of the C-type band v11 ~ 802 cm-2 has been analysed, and sextic distortion constants have been obtained for v8 = 1 at ~ 1301 cm-1 . The rotational constants of the two states are found to differ noticeably (20-100 standard deviations) from values reported earlier.

The discrepancies are believed to result in part from the availability of purely rotational data on v n and v 8 in the present study, but to originate primarily from the adoption of rather poor values of the ground state constants of 1,1-difluoroethylene in the earlier work on these two fundamentals.
Phase Diagram of the Orientationally Order-disorder Binary System 2,2-dimethyl-1,3-propanediol / 2,2-dimethyl-1,3-diaminopropane, [(CH3)2 C(CH2OH)2]x [(CH3)2C(CH2NH2)2]1-x · A Thermodynamic, X-ray, and 1H-NMR study
Authors: Strauss Roman , Braun Sigmar , Dou Shi-qi , Fuess Hartmut , Weiss Alarich
Published: February 2015

The phase diagram of the binary system [2,2-dimethyl-1,3-propanediol]x (1) / [2,2-dimethyl-1,3- diaminopropane]1-x (2) was studied by X-ray diffraction and DTA/DSC, for (2) also by 1H-NMR. The system is miscible over the whole concentration range 0 ≤ x ≤ 1 in the liquid state and in the plastic solid state, phase I, just below the melting point. At lower temperatures the system is demixing, and at room temperature two plastic mixed crystals coexist. The plastic phases of (1), (2), and (l)x(2)1-x crystallize face centered cubic, Fm3m, Z = 4, the lattice constants decreasing linearely with increasing x, and the lattice constants are: (1) a(327K) = 880.3 pm , (2) a(243K) = 905.6 pm. By single crystal X-ray diffraction the structure of the ordered phase II of (1) was refined at room temperature, monoclinic, P21/n, Z = 4, a = 596.9 pm, b = 1090.2 pm, c = 1011.0 pm, β = 99.74°. The results are in good agreement with the literature. The phase transition temperatures (in Kelvin) are T1→m = 399.2, TMm→1 = 399.7, T11→1 = 316.2, T1→11 = 308.2 for (1); = 300.2, = 301.7, T11→1 = 228.7, T1→n = 194.2 for (2). Strong hysteresis is observed for the transition T1→11 in (2). In the mixed systems (1)x(2)1-x, 0 < x < 1, the disordered phases do not order even by quenching to liquid nitrogen temperature. High resolution 1 H-NMR measurements are reported for phase I of (2) as a function of temperature. The “liquid” 1H-NMR spectrum is present far below the thermodynamic phase transition temperature T11-1, overlapping the wide line unresolved powder spectrum of phase II.
Notiz: Quantification of Symmetry
Authors: Novak Igor
Published: February 2015

A new mathematical criterion is suggested for symmetry ranking, i.e. determination of an “absolute symmetry scale” for discrete, finite groups. The criterion is based on both, the periods (orders) of each group element and the order of the group itself. This is different from the current criteria which consider only the orders of the groups themselves. The symmetry ranking, based on the new criterion, is applied to the symmetry point groups.
Investigation of the Reaction between Fe2O3 and Si Activated by Ball Milling
Authors: Concas Giorgio , Congiu Francesco , Corrias Anna , Muntoni Carlo , Paschina Giorgio , Zedda Daniela
Published: February 2015

The path of the reaction between Fe2O3 and Si, activated by high energy ball milling, has been investigated by X-ray diffraction and Mössbauer spectroscopy. Hematite reduction involves oxygen transfer from Fe to Si with the formation of intermediate phases containing Fe(II), which are then reduced to Fe(0). A steady state is reached in the milling process where the reduction of stoichiometric amounts of Fe2O3 and Si is not complete and an amount of Fe(II) in an amorphous matrix still remains. The same intermediate compounds are also observed in the milling process of mixtures with higher Fe2O3 /Si molar ratio.
The Microwave Spectrum of trans-2,3-Dimethyloxirane in Torsional Excited States
Authors: Hartwig H. , Dreizler H.
Published: February 2015

The microwave spectrum of trans-2,3-dimethyloxirane (CH3CHOCHCH3) in the excited tor-sional states υ17 = 1 and υ33 = 1 has been measured in the range from 8 to 26 GHz and assigned. An analysis of internal rotation splittings of the observed rotational transitions was performed using the internal axis method (or "combined axis method") with a newly developed program accounting for the top-top coupling. The threefold hindering potential V3 and the direction cosines λ g,i of the internal rotation axes i with respect to the principal inertia axes g are in a good agreement with the ground state values. Additionally, the sixfold hindering parameter V6 was found to be - 0.2600(12) kJ/mol. The value of the parameter V′12 describing the top-top coupling in the potential function (via V′12 sin 3 τ1 sin 3 τ2), was determined to -0.4240(6) kJ/mol.
Dielectric Behaviour of 1-(4-Isothiocyanatophenyl)-2-(4-hexyl- bicyclo[2,2,2]octane-1)ethane in Nematic and Isotropic Phases
Authors: Jadżyn J. , Legrand C. , Kędziora P. , Żywucki B. , Czechowski G. , Bauman D.
Published: February 2015

Static and dynamic investigations of the dielectric properties of the liquid crystal 1-(4-isothio-cyanatophenyl)-2-(4-hexyl-bicyclo[2,2,2]octane-1)ethane in the nematic and isotropic phases have been carried out in the frequency region from 1 kHz to 1 GHz. Two relaxation processes, described by the Debye functions, have been observed not only in the isotropic but also in the nematic phase, when the measurements of the electric permittivity vs. frequency have been made parallel to the orientation axis of liquid crystal. These processes are related to the rotation of the permanent dipole moment around two main molecular axes. The height of the potential barrier which hinders the rotation of the liquid crystal molecule around the short axis in the ordered nematic phase and the order parameter of the liquid crystal investigated have been estimated on the basis of the relaxation time values in the nematic and isotropic phases.
β-cyclodextrine and Water: Semiempirical Calculations
Authors: Margheritis C. , Sinistri C.
Published: February 2015

AM1 and PM3 calculations were carried out on ß-cyclodextrine (ß-CD) undecahydrate in the experimental conformation at 120 K. The calculated ß-CD/water interaction energies are very small and indicative for each water molecule of an unfavorable condition in respect to that of pure water. The conformationally optimized system was also studied: ß-CD appears highly symmetrical with negligible dipole moment, mainly because of the circular arrangement of the single vectors. Primary hydroxyls can easily rotate, while the secondary ones are stabilized by heteroannular hydrogen bonds and homoannular electrostatic interactions due to the consequent increase of the atomic charges. The ß-CD/water interaction energies in the optimized hydrated system are not significantly different from the experimental ones. This almost hydrophobic character is also shown by MM equilibrated solutions: all water molecules are rejected beyond 2.4 Å; between 2.4 and 2.9 Å highly structured water is present. From a purely enthalpic standpoint the molecule hydration appears highly improbable, thus the formation of ß-CD 11 H20 must involve a compensation mechanism.
Non-Linear Generalization of the Relativistic Schrödinger Equations
Authors: Ochs U. , Sorg M.
Published: February 2015

The theory of the Relativistic Schrödinger Equations is further developped and extended to non-linear field equations. The technical advantage of the Relativistic Schrödinger approach is demonstrated explicitly by solving the coupled Einstein-Klein-Gordon equations including a non-linear Higgs potential in case of a Robertson-Walker universe. The numerical results yield the effect of dynamical self-diagonalization of the Hamiltonian which corresponds to a kind of quantum de-coherence being enabled by the inflation of the universe.
Ion Acoustic Soliton in an Electron Beam Plasma
Authors: Chatterjee Prasanta , Roychoudhury Rajkumar
Published: February 2015

The pseudopotential method is used to study ion acoustic compressive and rarefactive solitons in an electron beam plasma with hot isothermal electron beam and plasma electrons and warm ions. It is shown that for small amplitude cases our results completely agree with the published results.
A Fundamental Structure of Continuum Mechanics I. Elastic Systems
Authors: Stuke Bernward
Published: February 2015

Continuum mechanics and thermodynamics are complementary areas of classical field theory. Their fundamental structure, however, is rather different according to the present view: on the one hand there is the equation of motion or the equivalent balance of momentum, on the other there is Gibbs' fundamental equation.

In a preceding paper it has been shown that systems having a potential of acceleration possess a structure of continuum mechanics which corresponds to the one of thermodynamics. This discussion is extended to elastic systems. In this case a tensorial potential of acceleration must be introduced. The equation of motion derived for this extended structure contains two additional terms (reactive forces) not present in the conventional balance of forces.
A Theoretical Study on Intramolecular Cyclization of Azidobenzotriazine to Tetrazolobenzotriazines
Authors: Asaad Adel N. , El Ashry El Sayed H.
Published: February 2015

The cyclization equilibrium of 3-azidobenzo[l,2,4]triazine (1 a) with tetrazolo[5,1-b]benzo[1,2,4] triazine (linear isomer, 1 b) and tetrazolo[5,1-c]benzo[1,2,4]triazine (angular isomer, 1 c) is investigated computationally using the molecular orbital MNDO-SCF method. The results suggest that the higher reactivity of atom N(4) with respect to N(2) towards the cyclization is due to: (i) The negative charge density upon N(4) is 1.3 time larger than that upon N(2); (ii) In the highest occupied molecular orbital (HOMO) the coefficient at N(4) is 2.4 times larger than that at N(2); (iii) The heat of reaction to (1 c) and (1 b) are calculated to be -74.9 and -14.8 kJ mol -1 , respectively; (iv) The thermodynamic stabilization of the angular isomer (1 c) is 60.1 kJ mol-1 larger than that of the linear isomer (1 b), and (v) The potential barrier heights calculated for the cyclization favour the angular product. From these considerations and the perturbation theory, the calculated yield of the cyclization reaction is 70.8±0.1% of 1 c, which is in good agreement with the experimental yield 64%.
Rayleigh-Taylor Instability of Viscous-Viscoelastic Fluids in Presence of Suspended Particles Through Porous Medium
Authors: Kumar Pardeep
Published: February 2015

The Rayleigh-Taylor instability of a Newtonian viscous fluid overlying an Oldroydian viscoelastic fluid containing suspended particles in a porous medium is considered. As in both Newtonian viscous-viscous fluids the system is stable in the potentially stable case and unstable in the potentially unstable case, this holds for the present problem also. The effects of a variable horizontal magnetic field and a uniform rotation are also considered. The presence of magnetic field stabilizes a certain wave-number band, whereas the system is unstable for all wave-numbers in the absence of the magnetic field for the potentially unstable configuration. However, the system is stable in the potentially stable case and unstable in the potentially unstable case for highly viscous fluids in the presence of a uniform rotation.
An EPR Study on VO2+ and Mn2+ Ions in Some Zeolites
Authors: Ucun F. , Köksal F.
Published: February 2015

The electron paramagnetic resonance (EPR) of hydrated VOSO4 ·3H2O and MnCl2 · 2H2O, adsorbed on the synthetic zeolites 3A, 4A, 5A and 13X of pore diameters 0.3, 0.4, 0.5, and 1.0 nm, respectively, and the natural zeolites heulandite and clinoptilolite was investigated. The spectra indicated that the coordination structures are VO(H2O)5
2+ and Mn(H2O)6
2+ , and that their EPR line widths vary with the pore diameters and the surface areas of the zeolites. The spectra of VO(H2O)5
2+ in natural zeolites at room temperature display an isotropic behavior and therefore indicate that the water ligands are mobile. The EPR spin Hamiltonian parameters, the molecule orbital constant ß2
*2 , and the Fermi contact term Keff were determined and are discussed. The spectra of Mn(H2O)6
2+ for narrow-pore zeolites indicate the existence of mobile and immobile water, whereas for wide-pore and natural zeolites they indicated the existence of only mobile water. The obtained Mn(H2O)6
2+ spectra are discussed.
Intensities and Widths of the Rovibrational Lines Observed in the 2ν5 Overtone Band of Cyanoacetylene
Authors: Yamada K.M.T. , Moravec A. , Niedenhoff M. , Winnewisser G.
Published: February 2015

The relative intensities and Lorentz half-widths of rovibrational transitions observed for the 2ν5 overtone band of cyanoacetylene, HCCCN, have been determined. The line widths and the intensities were obtained by fitting the observed line profiles with Voigt functions. The Lorentz half-width shows a clear J dependence and vanishes at J ~ 100. In the intensity calculation, we took into account the effects of the accidental resonances between the ν5 = 2 state and the (ν4 = 1, ν7 = 2) state as well as those of the generic l-type resonance. Peak intensities have been found not to be the appropriate presentation of the line intensity because of the strong J dependence of the half-width.
Distortion of the Benzene Ring in 1,2,3-Trifluorobenzene; A High-Resolution Molecular Beam Fourier Transform Microwave Study
Authors: Wolschendorf Ulrich , Kretschmer Uwe , Sutter Dieter H.
Published: February 2015

The results of a molecular beam microwave Fourier transform study of 1,2,3-trifluorobenzene and its monosubstituted 13C-isotopomers, all observed in natural abundance, are presented. Typically 30 transitions were observed for each isotopomer. Centrifugal perturbation theory up to fourth order was used to analyse the observed rotational spectra. Due to the high sensitivity and resolution of the spectrometer, very accurate vibronic ground state rotational constants can be reported:

They are used to derive a partial r0-structure. which shows the distortions of the benzene ring caused by fluorine substitution.
The Structure of Zinc Chloride Complexes in Aqueous Solution
Authors: Maeda M. , Ito T. , Hori M. , Johansson G.
Published: February 2015

The structure of zinc chloride complexes with different ratios of chloride to zinc, formed in concentrated ZnCl2 aqueous solutions, were determined from large-angle X-ray scattering using concentrations of the chloride complexes estimated by complementary Raman spectroscopic measurements. The highest chloro complex, [ZnCl4]2-, is tetrahedral with a Zn-Cl bond length of 2.294(4) Å. The trichloro complex, [ZnCl3]-, which coordinates one water molecule, is pyramidal with the Cl-Zn-Cl angle 111°. The Zn-Cl and the Zn-H2O bonds are 2.282(4) and 1.9 Å, respectively. The two lower complexes, [ZnCl2] and [ZnCl]+ , cannot be separated by Raman spectra. The average Zn-Cl distance in these complexes is 2.24 Å, and the average Zn-H2O distance is 1.9 Å. In [Zn(H2O)6]2+ the Zn-H2O distance is 2.15 Å.
Self-Diffusion in the Ionic Plastic Phase of (CH3 )3 NHClO4 Studied by 1H NMR and Electrical Conductivity
Authors: Ishida Hiroyuki , Furukawa Yoshihiro
Published: February 2015

Spin-lattice relaxation times (T1) and spin-spin relaxation times (T2) of 1H NMR and the electrical conductivity (σ) of trimethylammonium perchlorate were measured in the ionic plastic phase obtainable above 480 K. In this phase, both the cation and anion were revealed to perform self-diffusion. The activation energy (Ea ) of the cationic diffusion was evaluated to be 55 ± 4 and 50 ± 4 kJ mol-1 from 1H T1 and 1H T2 respectively, while Ea of the anionic diffusion was 64 ±3 kJ mol-1 from the electrical conductivity.
Description of the Glass Transition by a Percolation Blocking of Local Chemical Order
Authors: Blétry J.
Published: February 2015

A model for the liquid-glass transition, based on a percolation blocking of local chemical order, is proposed. The case of metallic liquids and glasses, whose structure is dominated by first neighbour chemical arrangement, is first treated. The chemical ordering "reaction" of the liquid phase is studied at thermodynamical equilibrium and the increase of the chemical order parameter with decreasing temperature is calculated. Within a given composition interval, however, a geometrical percolation process is shown to block this reaction below a "percolation temperature" (corresponding to null cooling rate) where the liquid is irreversibly frozen into a glass. The liquid-glass "phase diagram" is established and kinetic arguments, involving "frustrated" finite clusters which are formed close to the percolation threshold, provide an evaluation of the experimentally measured "glass transition temperature" as a function of cooling rate. The validity of this one order parameter model is then discussed with the help of the irreversible thermodynamics theory of Prigogine.

The formation of tetracoordinated glasses is explained by the formation of tetrahedral bonds, when the liquid temperature decreases, and represented by a "hole ordering" reaction. A general description of the structure of tetracoordinated glasses is thus achieved, which applies to amorphous silicon and germanium, 111 -V compounds, silica, amorphous water etc. Furthermore, an estimation of the temperature interval for the glass transformation of silica is obtained, which agrees well with experiment.

The existence of frustrated clusters gives to glasses a composite structure in the "medium distance order", which could explain the "fractal nature" of glass fracture surfaces down to the nanometer scale.
The Mercury-Sensitized Photolysis of Pentamethyldisilane
Authors: Kerst C. , Potzinger P. , Wagner H. Gg.
Published: February 2015

Two primary processes were observed in the Hg-sensitized photolysis of Me 5 Si 2 H: (I) hydrogen abstraction from the Si-H bond with a quantum yield of 0(1) = 0.85, (V) Si-Si bond breaking with 0(V) = 0.04. The hydrogen atoms formed in (/) undergo an H atom abstraction reaction (k(3)), as well as substitution reactions at the Si centers resulting in the formation of dimethylsilane and trimethylsilyl radical (k(4)) or trimethylsilane and dimethylsilyl radical (k(5)). The following branching ratios have been determined:

[xxx]

The ratio of disproportionation (k(2)) to combination (k(1)) for the pentamethyldisilyl radical has been determined with MeOH as the scavenger for 1-methyl-l-trimethylsilylsilene, 0.046 < k(2)/

A: C1) < 0.071. A mechanism with pertinent rate constants has been proposed which accounts for the

results.
Terahertz Spectrum of Trioxane
Authors: Klein H. , Belov S. P. , Winnewisser G.
Published: February 2015

The pure rotational spectrum of trioxane, (H2CO)3 the trimer of formaldehyde, has been recorded with high resolution in the frequency range between 326 and 947 GHz for the main isotopomer, the 13 C, and the 18O isotopic species in the vibrational ground state. These new high J and K data reveal that the molecule is fairly rigid. For the constants determinable from the recorded high J and K spectra (J = 90 and K = 75) the rotational constant

B = 5273.257 180(33) MHz,

the two quartic centrifugal distortion constants DJ, and DJK, and the three sextic constants HJ, HJK, and HKJ are needed in the fit to reproduce the measured spectra within experimental accuracy. In addition, for the 13C isotopomer the sextic constants HJK and HKJ are determined as well as the off-diagonal parameters d1 and d2.
The Rotational Spectrum and Nuclear Quadrupole Coupling of CH35C1F2
Authors: Blanco Susana , Lesarri Alberto , López Juan C. , Alonso José L. , Guarnieri Antonio
Published: February 2015

The rotational spectrum of CH35CIF2 in the ground vibrational state has been measured in the frequency range 8-18 GHz using a waveguide Fourier transform microwave (FTMW) spectrometer in order to determine accurate nuclear quadrupole coupling constants. The spectra of the excited vibrational states ν5 = 1, ν6 = 1 and ν9 = 1 have been also observed and analyzed in the frequency region 8-250 GHz using FTMW, Stark, and source modulation spectrometers. Quadrupole coupling constants are also reported for these states.
Resolution of constraints and gauge equivalence in algebraic Schrödinger representation of quantum electrodynamics
Authors: Stumpf H. , Pfister W.
Published: February 2015

The algebraic formalism of QED is expounded in order to demonstrate both the resolution of constraints and to verify gauge equivalence between temporal gauge and Coulomb gauge on the quantum level. In the algebraic approach energy eigenstates of QED in temporal gauge are represented in an algebraic GNS basis. The corresponding Hilbert space is mapped into a functional space of generating functional states. The image of the QED-Heisenberg dynamics becomes a functional energy equation for these states. In the same manner the Gauß constraint is mapped into functional space. By suitable transformations the functional image of the Coulomb forces is recovered in temporal gauge. The equivalence of this result with the functional version of QED in Coulomb gauge is demonstrated. The meaning of the various transformations and their relations are illustrated for the case of harmonic oscillators. If applied to QCD this method allows an exact derivation of effective color "Coulomb" forces, in addition it implies a clear conception for the incorporation of various algebraic representations into the formal Heisenberg dynamics and establishes the algebraic "Schrödinger" equation for quantum fields in functional space.
Novel Formulation of the Gibbs–Energy Change in Terms of Stoichiometrically Unique Response Reactions
Authors: Fishtik Ilie , Nagypál István , Gutman Ivan
Published: February 2015

The equation for the change of Gibbs energy in complex chemical systems is reformulated in terms of the newly conceived response reactions (RERs). The present formulation has the remarkable property of being unique: the composition of the species unequivocally determines the response reactions and via them the change of the Gibbs energy of the system. Furthermore, it enables one to reinterpret and rationalize some basic concepts of chemical thermodynamics, as coupling between reactions, sensitivity coefficients, etc.
The 33S Nuclear Quadrupole Coupling in the Rotational Spectrum of Methylthiirane
Authors: Lorenzo Felipe , Alonso José L. , Grabow J.-U. , Dreizler H.
Published: February 2015

As a first example in a series of substituted thiiranes we present an investigation of the nuclear quadrupole coupling in 33S-methylthiirane in natural abundance. The rotational and quadrupole coupling constants are: A = 11 599.0976(18) MHz, B = 4815.6822(6)MHz, C = 3909.1318 (5) MHz, χaa = -12.7731 (82) MHz, χbb = -20.3366(118) MHz, χcc = 33.1097(273) MHz.
Analysis of Internal Rotation and Determination of the Heavy Atom Structure of anti-2,3-Dimethylthiirane by Fourier Transform Microwave Spectroscopy
Authors: Hartwig Holger , Dreizler Helmut
Published: February 2015

We used the advanced technique of Fourier transform microwave spectroscopy to measure and assign the ground state rotational spectrum of anti-2,3-dimethylthiirane, and to analyse the internal rotation of the two methyl groups. The potential parameters obtained are V3 = 13.1678(21) and V12
' = -1.6678(25) kJ/mol. The measurement and assignment of the 13C and 34S isotopomers in the ground state allowed to determine the molecular structure of the heavy atom frame using the Τs and Τ0 methods.
The 33S Nuclear Quadrupole Coupling in the Rotational Spectrum of 2,2–Dimethylthiirane
Authors: Grabow Jens-Uwe , Onda Masao , Dreizler Helmut
Published: February 2015

The rotational spectrum of 33S 2,2-dimethylthiirane with its 33S nuclear quadrupole coupling hyperfine structure in the range 8.9 to 20.0 GHz and its analysis is reported. The rotational constants are A = 5507.4663(3), B = 3440.58395(18), and C = 2978.5723(3) MHz. The 33 S quadrupole coupling constants are χaa = -22.6390(23), χbb = 47.1830(50), and χcc = -24.5440(50) MHz.
Die Lösung der Schrödinger-Gleichung als eindimensionales Problem. IV. Erfassung von Korrelation am Beispiel der Zweielektronensysteme He und H2
Authors: Pernpointner M. , Preuß H.
Published: February 2015

After calculating ground and excited states of one-electron systems with improved discretization methods in Part III of this work it is shown that also correlation contributions can be yielded by this formalism. The more powerful discretization methods are applied to the two-electron systems He and H2. For multi-electron systems the symmetry properties of the wave function become important but in the case of two-electron systems an antisymmetric spin part can be separated and the integral kernel containing the spatial part of the wavefunction has therefore to be symmetric.
Additions of Cyclopentadiene to a Dissymmetric Maleic Anhydride: Semiempirical Calculations of Their Thermodynamics and Kinetics
Authors: Kuo Liang-Hsuan , Slanina Zdenĕk , Chou Teh-Chang
Published: February 2015

There are four conceivable products of the title addition, however only two of them have been prepared. MNDO, AM1, and PM3 quantum-chemical computations have been used in order to rationalize the observation. Activated complexes have been computed for the four possible additions and it was found that one C-C bond rather than two is created on the path from the reactants to the activated complex (the C-C bond varies between 1.70 and 1.87 A). Only one activated complex has been localized on each reaction path. The two types of products observed in experiment are computed to be both thermodynamically more stable and kinetically more feasible, and hence the computations agree with the observations.
Langjährige Be7 -Bodenluftmessungen lassen Änderung des atmosphärischen Austauschverhaltens während der letzten Jahrzehnte vermuten
Authors: Hartwig S.
Published: February 2015

An analysis covering three decades (1964-1994) of monthly Be7 ground-level-air concentration measurements at Braunschweig shows a systematic trend of the data. This trend is related to the yearly maximum/minimum concentration ratio. The observation may be due to a continuous mitigation of exchange processes between stratosphere and troposphere. This finding is commensurate with the hypothesis that, due to the growing concentration of anthropogenic infrared active gases, the heat source distribution in the stratosphere and consequently the eddy diffusivity and exchange process between stratosphere and troposphere are altered. This results in a shorter irradiation period of stratospheric air portions by cosmic rays and consequently can lower the concentration of isotopes of stratospheric origin in ground level air.
Notiz: Sulphate Rotator Phases in Polarised Light
Authors: Tärneberg Roy
Published: February 2015

Li2SO4 has a well defined high-conducting fee phase in the temperature range 577-860 °C, and LiNaSO4 a bcc phase in the range of 518-614 °C. Both salts were studied in polarised light during sequences going from melt, through the cubic phase into the "room temperature" phase, and back to the cubic phase. The two cubic sulphate phases are compared with organic plastic rotator phases, especially regarding the formation of vapour snakes.
New Unsaturated 1,8-Naphthalimide Dyes for Use in Nematic Liquid Crystals
Authors: Grabtschev Ivo K. , Moneva Ivanka T. , Wolarz Eryk , Bauman Danuta
Published: February 2015

The properties of new fluorescent dyes (derivatives of unsaturated 1,8-naphthalimide) are stud-ied. Spectral characteristics of the dyes are recorded in both isotropic (ethanol, dioxane) and anisotropic (nematogenic liquid crystal mixture ZLI 1840) media. The optical, electro-optical, and thermodynamical properties of the liquid crystal-dye mixtures are examined. The orientational order parameters are evaluated to be within 0.4 -0.5, depending upon the dye's molecular structure. Additionally, the influence of chemical bounding of the dyes to polystyrene chains on the phase transition temperature from the nematic to the isotropic state of polymer / liquid crystal mixtures is investigated. The low-molecular-mass dyes do not markedly affect the clearing point of pure liquid crystal, while the dye-styrene copolymers lower the transition temperature and widen the two-phase region at the transition. The electro-optical properties of the dye / liquid crystal systems imply potential utilization of the dyes studied in the so called "guest-host" liquid crystal displays.
Crystal Structure Refinement and Single Crystal 81Br Zeeman NQR Study of KHgBr3· H2O
Authors: Terao Hiromitu , Okuda Tsutomu , Uyama Sachiyo , Negita Hisao , Dou Shi-qi , Fuess Hartmut , Weiss Alarich
Published: February 2015

Three 81Br NQR resonance lines of KHgBr3 ·H2O were detected between 77 K and room temperature. From the Zeeman effect measurement on a single crystal the nuclear quadrupole coupling constants (e2qQ/h) and the asymmetry parameters (ƞ) were obtained, which are 228.42 MHz and 0.005, 226.24 MHz and 0.005, and 108.76 MHz and 0.465 for e2qQ/h and ƞ at 295 K, respectively. Large deviations of the observed directions of electric field gradient tensors from the directions expected from previous X-ray results have been found. With the present X-ray redetermination, 81Br NQR and structure are in good agreement. The structure and bonding in the compound are discussed.
The Structure of a Zn(II) Metaphosphate Glass. I. The Cation Coordination by a Combination of X-Ray and Neutron Diffraction, EXAFS and X-Ray Anomalous Scattering
Authors: Bionducci M. , Licheri G. , Musinu A. , Navarra G. , Piccaluga G. , Pinna G.
Published: February 2015

In order to clarify the reason of some discrepancies existing in literature, the zinc coordination in a Zn metaphosphate glass has been investigated by the complementary use of X-Ray Diffraction, Neutron Diffraction, Extended X-ray Absorption Fine Structure Spectroscopy and X-Ray Anoma-lous Scattering. All the techniques indicate a tetrahedral coordination of O atoms around Zn :+ ions, the Zn-O distance being 1.94 ± 0.01 Å. The simultaneous modelling of all the experimental data by Reverse Monte Carlo technique demonstrated that this coordination is consistent with an extended model in which metal ions are interposed between phosphate chains. The importance of describing the preparation conditions of the glasses is stressed when structural results have to be compared.