bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simplified Approach to the Density Functional Theory of Molecules
Authors: Kollmar Christian
Published: February 2015

A simplified molecular orbital (MO) formalism based on density functional theory is developed. Starting from the same energy expression as Kohn-Sham theory the electronic density is expanded in terms of atomic mono-center densities. Application of the variational principle leads to a secular matrix with a particularly transparent structure which allows the definition of a resonance integral taking into account the effect of interference in a natural way. The construction of the secular matrix scales formally as N2 instead of N3 in the Kohn-Sham formalism with N being the dimension of the atomic orbital (AO) basis set.
Study of Water and Dimethylformamide Interaction by Computer Simulation
Authors: Cordeiro João Manuel Marques , Gomide Freitas Luiz Carlos
Published: February 2015

Monte Carlo simulations of water-dimethylformamide (DMF) mixtures were performed in the isothermal and isobaric ensemble at 298.15 K and 1 atm. The intermolecular interaction energy was calculated using the classical 6-12 Lennard-Jones pairwise potential plus a Coulomb term. The TIP4P model was used for simulating water molecules, and a six-site model previously optimised by us was used to represent DMF. The potential energy for the water-DMF interaction was obtained via standard geometric combining rules using the original potential parameters for the pure liquids. The radial distribution functions calculated for water-DMF mixtures show well characterised hydrogen bonds between the oxygen site of DMF and hydrogen of water. A structureless correlation curve was observed for the interaction between the hydrogen site of the carbonyl group and the oxygen site of water. Hydration effects on the stabilisation of the DMF molecule in aqueous solution have been investigated using statistical perturbation theory. The results show that energetic changes involved in the hydration process are not strong enough to stabilise another configuration of DMF than the planar one.
The Oxidation Kinetics of Thin Copper Films Studied by Resistivity Measurements
Authors: Rauh M. , Finzel H.-U. , Wißmann P.
Published: February 2015

Resistivity measurements on thin metal films allow to study the kinetics of oxidation. The method is applied to 50 - 60 nm thick copper films deposited on glass substrates under UHV conditions. After annealing at 150°C, the films are exposed to pure oxygen at various temperatures in the range 85 -135°C, and the electrical resistivity is recorded in situ. At these temperatures, the oxygen begins to penetrate into the interior of the films, which results in a relatively steep increase in the film resistivity. A linear time law is valid to good approximation, which can be attributed to the influence of the dissociation of an adsorbed molecular species of oxygen on the reaction velocity. A potential diffusion of oxygen in the grain boundaries is also discussed.
Pure Rotational Spectra of CS
Authors: Ahrens V. , Winnewisser G.
Published: February 2015

The pure rotational spectra of CS and its isotopomers 12C 33S, 12C 34S, 13C 32S, 13C 33S, 13C 34S including the very rare isotopomer 12C 36S were observed. The rotational spectra include ground and vibrationally excited transitions up to v = 16. The new measurements have been performed with the Cologne terahertz spectrometer covering the frequency region from 259 to 1075 GHz. These newly observed rotational transitions together with earlier data were fitted to a Dunham-type Hamiltonian. The obtained isotopically invariant parameters include vibrational and rotational expansion coefficients.
An EPR Study of Mo5+ Introduced into NaY Zeolites by Solid-State Reactions
Authors: Ucun F. , Sağlam A. , Köksal F. , Bahçeli S.
Published: February 2015

By means of an EPR investigation of Mo5+ ions introduced into NaY zeolites by solid-state reactions, the location and coordination of Mo5+ in zeolites were investigated. Two different locations, free and distorted tetrahedral, were found. The molecular orbital coefficient, ß2 , and the effective charge, Q, for the MO5+ ions in a distorted tetrahedral structure were calculated and interpreted.
Structural and Dynamic Approaches of Molten Salts by High Temperature Spectroscopies
Authors: Bessada C. , Lacassagne V. , Massiot D. , Florian P. , Coutures J.-P. , Robert E. , Gilbert B.
Published: February 2015

The combination of 27AI NMR expriments and Molecular Dynamics simulation confirms the exis-tence of penta-coordinated Aluminium in several molten aluminium oxides. In the case of fluoroalumi-nate molten salts, NMR and Raman spectroscopies provide complementary approaches leading to a structural description in term of AIF−
4, AlF5
2-and AlF6
3−species.
High Pressure Dielectric Studies of 8CB in the Isotropic, Nematic, and Smectic A Phases
Authors: Markwick Phineus , Urban Stanislaw , Würflinger Albert
Published: February 2015

The static and complex permittivity of 4-n-octyl-4'-cyanobiphenyl (8CB) has been measured for the isotropic, nematic and smectic A phases as functions of temperature and pressure. The ranges of 297 - 361 K, 0.1 - 220 MPa, and 0.1 - 13 MHz, were covered. Only the parallel component of the complex permittivity, ɛ*( f ) = ɛ' ( f ) - iɛ"(f), was measured. The relaxation times T||
(p, T) as well as Tis(p, T) were analysed at constant temperature, pressure and volumes yielding the activation volume, Δ ≠V(T), activation enthalpy Δ≠H(p), and activation energy Δ≠U(V), respectively. All activation parameters calculated for the smectic A phase of 8CB are smaller than those obtained for the nematic phase. The activation energy constitutes approximately half of the activation enthalpy value in all three phases studied. The pressure study allowed to calculate the pressure dependence of the retardation factor g
|| (p, T), from which the nematic potential q(p,T) can be derived. Using the relationships between g\\ and q/ RT proposed by Kalmykov and Coffey, the order parameter (P2(p, T)) was calculated as a function of pressure.
Differential Scanning Calorimetry (DSC) under High Pressure on 10-TPEB
Authors: Masberg S. , Ernst C. , Schneider G. M. , Würflinger A. , Dąbrowski R.
Published: February 2015

The phase behaviour of a new liquid crystal, belonging to the series l-[4-n-alkyl-biphenyl]-2-[4-isothio-cyanato-phenyl]ethane (nTPEB), n = 10, has been investigated with differential scanning calorimetry at ambient and high pressure. The phase behaviour depends on the thermal treatment. Phase transition temperatures have been determined as a function of pressure up to 300 MPa. No pressure-induced or pressure-limited phases are observed in this pressure range. Enthalpy-and volume-changes accompanying the phase transitions have been calculated using the Clausius-Clapeyron equation.
Dromion Interactions of a (2+1)-Dimensional sine-Gordon Equation
Authors: Ruan Hang-yu , Chen Yi-xin
Published: February 2015

Starting from two line solitons, the solution of an integrable (2 + 1)-dimensional sine-Gordon equation in bilinear form yields a dromion solution that is localized in all directions for a suitable potential. The interaction between two dromions is studied in detail through the method of figure analysis. For different selections of parameters, the interactions between two dromions may be elastic, not completely elastic, or completely inelastic.
J-Modulation in ID NMR 1H Spectrum of Taurine and Aspartate Using Spin-Echo Technique
Authors: Oturak Halil , Sağlam Adnan , Bahçeli Semiha
Published: February 2015

This study reports on a theoretical calculation of Hahn's spin-echo experiment in case of a model A2B2 spin system with a strongly coupling character and gives the experimental results of one-dimension 1H high-resolution NMR spectra of taurine and aspartate. The calculated amplitudes of the spin-echoes for two different proton groups of taurine are given. Using results of our calculations for taurine, the computer simulations of J-modulation are implemented. It is shown that the agreement be-tween the experimental and simulated spectra is good.
Effective Pair Potentials and Structure of Water
Authors: Cordeiro J. M. M.
Published: February 2015

Classical Monte Carlo calculations have been performed in order to investigate the ability of the TIP4P, SPC, and SPCE water models to reproduce the structural features of liquid water. The simulations were carried out in the NPT ensemble at 4 thermodynamic conditions. The results are compared with recent neutron diffraction data. Essentially, the three models capture equally well the thermodynamic and structural features of water. Although they were parametrized to reproduce the water properties at ambient conditions, the agreement with the experimental pair correlation functions was even better at super-critical conditions. This is because the effective pair potentials have some difficulty to re-produce cooperative interactions, like hydrogen bonds. These interactions are less effective at super-critical conditions, where the liquid behaves roughly like a gas
Internal Mobilities in the Molten Ternary System (Li,K,Cs)N03 of the Eutectic Composition
Authors: Chou Pao-Hwa , Takagi Ryuzo , Okada Isao
Published: February 2015

The ε values in the internal cation mobilities of (Li,K,Cs)NO3 of the eutectic composition (35.2-39.8-25.0 mol%) in the temperature range from 453 to 673 K were measured by Klemm's countercurrent electromigration method, where e is defined as (bi-bj)/ba; ba is the average internal cation mobility and the subscripts i and j refer to any two out of these three cations. The conductivity was measured by a direct current method. From these data and the molar volume calculated from those of the pure salts on the assumption of additivity, the internal cation mobilities, bLi , bK and bCs, have been calculated. The bLi is well expressed by the empirical equation presented for binary alkali nitrates; the negative devia-tion for bK and bCs may be accounted for on the assumption of the tranquilization effect of Li+. The orders of those internal cation mobilities are bCs<bK<bLi at 453-473 K, bCs<bLi<bK at 473 -583 K, and bLi<bCs<bK at 583-673 K. These orders can be interpreted in terms of the dynamic dissociation model previously presented.
Second Harmonic Resonance on the Surface of a Magnetohydrodynamic Fluid Column
Authors: Lee Doo-Sung
Published: February 2015

The method of multiple scales is used to analyse the second harmonic resonance of weakly nonlinear progressive waves on the surface of a fluid column in the presence of a magnetic field. The dynamical equations governing the second harmonic resonance are obtained. Numerical results are given graphically.
Pressure and Isotropic-Nematic Transition Temperature of Model Liquid Crystals
Authors: Hess Siegfried , Su Bin
Published: February 2015

The pressure in the gaseous, the isotropic liquid and nematic liquid crystalline states, as well as the isotropic-nematic transition temperature are calculated for a model system composed of non-spherical particles. The potential is a generalization of the Lennard-Jones interaction where the attractive part depends on the relative orientations of the particles and the vector joining their centers of mass. Point of departure is an augmented van der Waals approach. It involves a modified Carnahan-Starling expression associated with the repulsive part of the interaction, and an orientation dependent second virial coefficient, as well as the orientational distribution functions of a pair of particles, linked with the attractive part of the potential. In a high temperature approximation, and for a special choice of model parameters, results are presented and displayed graphically.
Stoichiometry Effects on the Electrical Conductivity of Lithium-Manganese Spinels
Authors: Azzoni C. B. , Mozzati M. C. , Paleari A. , Bini M. , Capsoni D. , Massarotti V.
Published: February 2015

The electrical conductivity of lithium-manganese spinels is analyzed in samples with different starting Li cationic fraction x. Li-rich spinels, resulting from Li-Mn substitution around the stoi-chiometric value (x= 0.333), show conductivity values higher than that observed in stoichiometric LiMn2O4 . Besides, a conductivity drop, associated with a structural phase transition at about 290 K in LiMn2O4 , progressively disappears by decreasing x, while it is absent in Li-rich samples. Stoi-chiometry effects on the concentration of charge carriers and on the available sites for the hopping transport process are evaluated, as well as the effects due to coexisting insulating phases. The role of the Jahn-Teller effect on the conductivity behaviour of stoichiometric and Li-poor spinels is also considered.
DSC Investigations of the Phase Transitions of [M(NH3 )6](ClO4)2 and [M(NH3)6](BF4)2 , where M = Co and Cd
Authors: Migdał-Mikuli A. , Mikuli E. , Wróbel S. , Hetmańczyk Ł.
Published: February 2015

Solid polymorphism of four compounds of the type [M(NH3)6](XY4)2 , where M = Co2+ or Cd2+ , and XY4 = ClO4
- or BF4
- has been studied at 100 -300 K by DSC. One or two phase transitions of the investigated compounds have been found. For the compounds with M = Co the phase transitions have not yet been described in the literature. For the compounds with M = Cd the phase transition-temperature is in good agreement with the results obtained by NMR and EPR. Generally, for [M(NH3)6](BF4)2 compounds (M = Mg, Fe, Co, or Ni) the phase transition temperature TCl is lower than that for the corresponding [M(NH3)6](ClO4)2 , but for compounds with M = Cd it is higher. However, the enthalpy and entropy changes at the TCI phase transitions of [M(NH3)6](BF4)2 are always lower than those for [M(NH3)6](ClO4)2. Moreover, for the compounds of this type a correlation between the transition temperature TCl and the crystal lattice parameter a has been found.
DSC Investigations of the Phase Transitions of [M(H2O)6](NO3)2 , where M = Mn, Co, Ni, Cu and Zn
Authors: Mikuli E. , Migdał-Mikuli A. , Wróbel S. , Grad B.
Published: February 2015

The phase transitions of [M(H2O)6 ](NO3)2 , where M = Mn2+ , Co2+ , Ni2+ , Cu2+ or Zn2+ have been studied at 100 -400 K by DSC. Two phase transitions connected with a two-stage melting process have been found for these five compounds. For the compound with M = Co, besides the two melting points a solid-solid phase transition at 272 K has been found.
Dielectric Relaxation of Hexadeutero Dimethylsulfoxide
Authors: Betting H. , Stockhausen M.
Published: February 2015

The dielectric relaxation parameters of the title substance (DMSO-d6) in its pure liquid state are determined from meas-urements up to 72 GHz at 20°C in comparison to protonated DMSO. While the relaxation strengths do not differ, the relax-ation time of DMSO-d 6 is significantly longer (21.3 ps) than that of DMSO (19.5 ps).
Nonlinear Analysis of Individual Quantum Events in a Model with Bohm Trajectories
Authors: Bräuer Kurt
Published: February 2015

The quantum mechanical model under consideration describes a particle beam under the influence of an oscillator. Bohm’s causal interpretation of quantum mechanics is used to calculate trajectories of the particles. Individual quantum events are defined by the intersection of the beam particle trajectories and the particle detector. The time sequence of individual quantum events is interpreted as a time series and is analyzed by linear and nonlinear methods, which involves reconstruction and investigation of the system in an embedding space. The Fourier amplitudes and the fill factors show white noise, however the Karhunen-Loeve components indicate the influence of the oscillator on the beam particles. In this model individual quantum events carry information which can be detected by the Karhunen-Loeve ex-pansion.
Medium Range Structure of Hydrogenated Amorphous Ti84Si16
Authors: Pojtinger A. , Lamparter P. , Steeb S.
Published: February 2015

Amorphous melt-spun Ti84Si16 was investigated by small angle neutron scattering (SANS) in the blank state as well as after loading with hydrogen or deuterium. The integrated intensity and the fractal dimension of the SANS signal change strongly with increasing H, D content. A model is proposed which explains the changes of the scattering signal. By means of this model it is concluded that melt-spun amorphous Ti84Si16 consists of two types of regions. The first type contains pure Ti and the composition of the second type is Ti80Si20-The inner surfaces between these types of regions have fractal features.
Correlated Atomic Pair Functions by the e-ϱ-Method. I. Ground State 11S and Lowest Excited States n1S (n > 1) and n3S of Helium
Authors: Seelig F. F. , Becker G. A.
Published: February 2015

Some low n1S and n3S states of the helium atom are computed with the aid of the e-e method which formulates the electronic wave function of the 2 electrons ψ = e-e F, where ϱ=Z(r1+r2)–½r12 and here Z = 2. Both the differential and the integral equation for F contain a pseudopotential Ṽ instead of the true potential V that contrary to V is finite. For the ground state, F = 1 yields nearly the Hartree-Fock SCF accuracy, whereas a multinomial expansion in r1, r2 , r2 yields a relative error of about 10-7 . All integrals can be computed analytically and are derived from one single “parent” integral.
Computer Simulation of Chiral Liquid Crystal Phases IX. Chiral Induction in Guest-host Systems - Calculation of the Helical Twisting Power
Authors: Memmer Reiner , Janssen Folkert
Published: February 2015

The chiral induction in liquid crystalline phases was studied by Monte Carlo simulation of the chiral Lebwohl-Lasher model. Binary guest-host systems composed of achiral and chiral molecules as well as of different chiral molecules were investigated in dependence on the composition. A cholesteric phase was induced by dissolving a small fraction of chiral molecules in a nematic phase. For dilute solutions the equilibrium pitch was found to be a linear function of the chiral dopant concentration. Independent of system size effects the application of self-determined boundary conditions enabled the determination of the symmetry adapted quantities for the chiral induction, the helical twisting power (HTP) and the achiral helical twisting power (AHTP). Additionally, a different orientational behaviour of enantiomeric dopants in the chiral surroundings of a cholesteric host phase has been determined.
Dynamics of Two-Dimensionally Arranged n-Octylammonium Ions Intercalated into Tetrasilicicfluormica
Authors: Yamauchi Miho , Ishimaru Shin’ichi , Ikeda Ryuichi
Published: February 2015

The dynamic behaviour of n-octylammonium ions intercalated into tetrasilicicfluormica was investigated by measuring 1H and 2H solid state NMR spectra and 1H spin-lattice relaxation times. X-Ray diffraction measurements revealed that the cations are arranged with the long axis parallel to the clay sheet. Uniaxial rotation of cations was found to take place above ca. 200 K among non-equivalent potential wells made by clay sheets. As a new type of 2-D motion mode, whole cationic in-plane tumbling in the 2-D layer seems to be excited above ca. 450 K. The obtained results are compared with those previously reported on saponite of an analogous structure.
Quantum Reflection of Ultracold Atoms in Magnetic Traps
Authors: Xie Rui-Hua , Brumer Paul
Published: February 2015

Ultracold neutral atoms can be trapped in spatially inhomogeneous magnetic fields. In this paper, we present a theoretical model and demonstrate by using Landau-Zener tool that if the magnetic resonant transition region is very narrow, "potential barriers" appear and quantum reflection of such ultracold atoms can be observed in this region.
Coherent Control Theory of off Resonance Refractive Index of Medium with a Gaussian Pulse of Coherent Light
Authors: Xie Rui-Hua , Brumer Paul
Published: February 2015

In this paper we develop a coherent control theory of the off resonance refractive index of a medium with a Gaussian pulse of coherent light. The refractive index of gaseous Ni is studied by using this theory. It is found that the off resonance refractive index of gaseous N2 can be enhanced through the coherent control approach by changing the coherent parameters or the pulse duration of the coherent light.
Electron Paramagnetic Resonance of Cu2+ in KHC03 Single Crystals
Authors: Köksal F. , Kartal İ. , Karabulut B.
Published: February 2015

The electron paramagnetic resonance spectra of Cu2+ doped KHC03 single crystals were studied at room temperature. The results indicate a substitutional entrance of the Cu2+ ions in place of the magnetically inequivalent K+ sites. The charge compensation is supposed to be fulfilled by proton vacancies. The hyperfine lines were well resolved and the 65Cu hyperfine coupling tensors were also found. The ground state of Cu2+ indicates the dominance of the dx
2-
y
2 orbital and, therefore, elongation of the polyhedron, similar to a lengthened octahedron.
A Search for Isotope Effects in Chemiluminescent Reactions of Metastable Ca*( 3Pj, 1D2 ) Atoms with CH3I and CD3I Molecules
Authors: Pranszke B. , Kierzkowski P. , Kowalski A.
Published: February 2015

Chemiluminescent reactions of calcium atoms in the metastable 3Pj and 1D2 states with CH3I and CD3I were studied in a beam-gas arrangement. Calcium monoiodide spectra associated with transitions from the electronic A 2Π, B 2Σ+ and C 2Π states to the X 2Σ+ ground state were recorded. Total collision and chemiluminescence cross sections were measured. It was found that isotopic substitution in the methyl group does not change the reaction cross sections and the chemiluminescence spectra.
Solitary Wave Solutions of High Order Scalar Fields and Coupled Scalar Fields
Authors: Yang Jian-song , Lou Sen-yue
Published: February 2015

An arbitrary Klein-Gordon field with a quite general constrained condition (which contains an arbitrary function) can be used as an auxilialy field such that some special types of solutions of high order scalar fields can be obtain by solving an ordinary differential equation (ODE). For a special type of constraint, the general solution of the ODE can be obtained by twice integrating. The solitary wave solutions of the model ф5 are treated in an alternative simple way. The obtained solutions of the ф5 model can be changed to those of the ф8 field and coupled scalar fields.
Phase Transitions in Crystalline [Me(H20)6 ](BF4 )2. Part I (Me = Mn, Fe, Co, Ni and Zn)
Authors: Mikuli E. , Migdał-Mikuli A. , Wróbel S.
Published: February 2015

Solid polymorphism in five compounds of the type [Me(H20)6](BF4)2 , where Me = Mn, Fe, Co, Ni and Zn, have been studied in the temperature range 120 -330 K by DSC. For each substance at least three solid modifications have been found. In addition, for compounds with Me = Mn, Fe and Zn some new low temperature phase transitions have been observed. The transition temperatures for the [Me(H2O)6](BF4)2 compounds are distinctly lower than those for the [Me(H2O)6](ClO4)2 compounds. The entropy-and enthalpy-changes at the phase transitions of the hexaaquametal(II) tetrafluoroborates are significantly lower than those for the corresponding chlorates(VII). Linear correlations between the highest transition temperature and the crystal density are found for both series of these isomorphous compounds.
MINDO Forces Study of the Uncatalysed and Acid-Catalysed Friedel-Crafts Reactions Between CH3F and CH4
Authors: Abed Amel G. , Khalil Salim M.
Published: February 2015

MINDO-forces calculations have been performed on the uncatalysed and acid-catalysed Friedel-Crafts reaction between CH3F and CH4 . It has been found that the catalysed reaction is exothermic, spontaneous and has a smaller potential-energy barrier than the uncatalysed reaction. The mechanisms for uncatalysed and catalysed reactions are discussed.
EPR Studies of Cu2+ in dl-Aspartic Acid Single Crystals
Authors: Karabulut B. , Tapramaz R. , Bulut A.
Published: February 2015

EPR studies of Cu2+ doped dl-Aspartic Acid [NH2CH(CH2COOH)COO] powder and single crystal have been carried out at 113 and 300 K. The principal hyperfine and g values, covalancy parameter, mixing coefficients and Fermi-contact term of the complex were obtained, and the ground-state wavefuntion of the Cu2+ ion in the lattice has been constructed.
Ertel's Potential Vorticity and Irreversible Processes
Authors: Schröder Wilfried , Treder Hans-Jürgen
Published: February 2015

According to Ertel's potential vorticity the thermodynamical parameters in the equation of state define the forces which move the vortices and modify them in space and time.
Exact Solitary-wave Solutions for the General Fifth-order Shallow Water-wave Models
Authors: Hong Woo-Pyo , Jung Young-Dae
Published: February 2015

We perform a computerized symbolic computation to find some general solitonic solutions for the general fifth-order shal-low water-wave models. Applying the tanh-typed method, we have found certain new exact solitary wave solutions. The pre-viously published solutions turn out to be special cases with restricted model parameters.
Monte Carlo Calculation of the Correlation Functions for Molecular Rotation-Application to NMR
Authors: Goc Roman
Published: February 2015

The Monte Carlo method for calculating correlation functions for the rotational motion of atoms is presented. This method applies to crystalline solids and allows the determination of the correlation functions for any model of rotating atoms, molecules or ions constituting the material of interest, if only its crystal structure is known. The presented method permits the calculation of the correlation functions for a whole block of unit cells, not only for a single group of particles. The described method can be employed to calculate correlation functions used in the theoretical description of NMR, dielectric or neutron diffraction experiments. As an example the correlation functions and NMR relaxation time T1 of solid benzene are calculated by the Monte Carlo method for the.
Dielectric Studies of 4-w-Hexyloxy-4’-Cyanobiphenyl (60CB) at Elevated Pressure
Authors: Urban S. , Smoluchowski M.
Published: February 2015

The principal dielectric permittivity components in the nematic phase of 4-rc-hexyloxy-4’-cyanobiph-enyl (60CB) were measured as functions of temperature at ambient pressure and as functions of pres-sure up to 100 MPa at several constant temperatures. The dielectric anisotropy is analized in the frame of the Maier-Meier equations. The pressure dependence of the order parameter is deduced. Preliminary results for the activation volume and activation enthalpy from the pressure and temperature dependenc-es of the longitudinal relaxation times are obtained.
EPR Spectra of VO2+ Doped Ammonium Oxalate Monohydrate Single Crystals
Authors: Karabulut B. , Tapramaz R.
Published: February 2015

The EPR spectra of VO2+ ions in ammonium oxalate monohydrate, [(NH 4)2C2O4-H2O], single crystals have been studied at room temperature and at 113 K in mutually three perpendicular planes. The spin Hamiltonian parameters are determined using a numerical technique together with a trial and error procedure to resolve the single crystal spectra. The parallel and perpendicular components of axially symmetric g and hyperfine tensors for VO2+ ion in ammonium oxalate monohydrate single crystal are determined, and the results are discussed.
New Non-traveling Solitary Wave Solutions for a Second-order Korteweg-de Vries Equation
Authors: Hong Woo-Pyo , Jung Young-Dae
Published: February 2015

Modeling the propagation of two different wave modes simultaneously, the second-order KdV equation is of current interest. Applying a tanh-typed method with symbolic computation, we have found certain new analytic soliton-typed solutions which go beyond the the previously obtained traveling wave solutions.
Ground-and Excited-State Dipole Moments of 6-Propionyl-2-(dimethylamino)naphthalene Determined from Solvatochromic Shifts
Authors: Kawski A.
Published: February 2015

The dipole moments in the ground-and excited-state of the fluorescence probe 6-propionyl-2-(dim-ethylamino)naphthalene (PRODAN) are determined from solvatochromic shifts to μe = 2.1 D and μg = 6.4 D. These values concern the free molecule. In the first excited singlet state the dipole moment is only 3 times greater than in the ground state.
Dielectric Relaxation Study of Some Solutions Containing β-Cyclodextrin and Dimethylsulfoxide
Authors: Betting H. , Stockhausen M.
Published: February 2015

Dielectric spectra have been measured up to 72 GHz at 20°C for solutions of β-cyclodextrin (CD) in the following solvents over the whole solubility range of CD: dimethylsulfoxide (DMSO), DMSO/ 1,4-dioxane mixture (2:1 molar ratio), DMSO/water mixtures (2:1 and 1:2). The spectra are analyzed into a sum of Debye type spectral components. These are likely to be caused by different physical pro-cesses. The discussion shows (i) that there is a preferential CD-DMSO interaction, by far exceeding the CD-water interaction, and (») that, concerning CD-DMSO, a loose interaction can be distinguished from the formation of an inclusion complex.
Heat Capacity of the Rb3LnCl6 Compounds with Ln = La, Ce, Pr, Nd
Authors: Rycerz L. , Gaune-Escard M.
Published: February 2015

The heat capacities of the solid and liquid Rb3LnCl6 compounds, where Ln = La, Ce, Pr, Nd, have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. The heat capacity shows a small decrease with increasing temperature from the temperature of phase transition up to 150 -200 K above this transition for the Rb3CeCl6, Rb3PrCl6 and Rb3NdCl6 compounds. The measured heat capacities were used to calculate the formation enthalpy of the liquid phase. The results obtained compare satisfactorily with the known experimental data.
The Effects of Collisions with Neutral Particles on the Instability of Two Superposed Composite Plasmas Streaming Through Porous Medium
Authors: El-Sayed Mohamed Fahmy
Published: February 2015

The effects of collisions with neutral atoms on the hydromagnetic stability of the plane interface separating two streaming superposed composite plasmas of uniform densities in a porous medium are investigated. In the absence of fluid velocities, it is found, for a potentially stable configuration, that the system remains stable, while for a potentially unstable configuraion, the unstable system becomes stable under a certain condition of the wavenumber depending on the values of the fluid densities, Alfvén velocities, and the orientation of the magnetic field. The porosity of the porous medium does not have any significant effect on the stability criterion. In the presence of fluid velocities, it is found that, the instability criterion is independent of the permeability of the medium and the collision effects with neutral particles. The criterion determing the stability does not depend on the permeability of the medium but depends on the density of neutral particles. The porosity of the medium is found to have a significant effect on both the stability and instability criteria in this case. The role of the permeability of the medium, the collisional frequency, and the porosity of the porous medium on the growth rate of the unstable mode is examined analitically. Routh’s test of stability is applied to confirm the above results.
Dynamic Solvent Effects in the Degenerate Isomerization of a Hexafluoroacetone Anil Studied by High-Pressure 19 F NMR
Authors: Ohga Yasushi , Asano Tsutomu , Karger Norbert , Gross Thomas , Lüdemann Hans-Dietrich
Published: February 2015

The rate of the degenerate isomerization of N-hexafluoroisopropylidene-N’,N’-dimethyl-ρ-phe-nylenediamine was measured by high-pressure 19F NMR spectroscopy in a viscous hydrocar-bon, 2,4-dicyclohexyl-2-methylpentane. Pressure-induced retardations that cannot be rationalized within the framework of the transition state theory (TST) were observed, and it was concluded that the reaction was cast into the TST-invalid nonequilibrium conditions by high pressure.
NMR Studies on Dynamics of Water Intercalated in Clay Minerals
Authors: Ishimaru Shin’ichi , Ikeda Ryuichi
Published: February 2015

The dynamics of water molecules intercalated in D2O saturated synthetic and natural smectites, and a synthetic Na-fluormica were studied by measurements of solid state 2H NMR spectra and spin-lattice relaxation times at 150 - 370 K. The obtained results could be explained by the 2-site flip, the C2 rotation and the isotropic rotation of the D2O molecules in smectites. In fluormica, the isotropic motion was undetectable, but the axial rotation of the hydration sphere as a whole was observed. The activation energies and correlation times of the C2 rotation were almost independent of the interlayer cations but depended on the character of clay-layers.
Hydrogen Bonds in Crystalline Imidazoles Studied by 15N NMR and ab initio MO Calculations
Authors: Ueda Takahiro , Nagatomo Shigenori , Masui Hirotsugu , Nakamura Nobuo , Hayashi Shigenobu
Published: February 2015

Intermolecular hydrogen bonds of the type N-H...N in crystals of imidazole and its 4-substituted and 4,5-disubstituted derivatives were studied by 15N CP/MAS NMR and an ab initio molecular orbital (MO) calculation. In the 15N CP/MAS NMR spectrum of each of the imidazole derivatives, two peaks due to the two different functional groups, >NH and =N-, were observed. The value of the 15N isotropic chemical shift for each nitrogen atom depends on both the length of the intermolecular hydrogen bond and the kind of the substituent or substituents. It was found that the difference between the experimen-tal chemical shifts of >NH and =N-varies predominantly with the hydrogen bond length but does not show any systematic dependence on the kind of substituent. The ab initio MO calculations suggest that the hydrogen bond formation influences the 15N isotropic chemical shift predominantly, and that the difference between the 15N isotropic chemical shift of >NH and =N-varies linearly with the hydrogen bond length.
Pulse Power Compression by Cutting a Dense Z-Pinch with a Laser Beam
Authors: Winterberg F.
Published: February 2015

A thin cut made through a z-pinch by an intense laser beam can become a magnetically insulated diode crossed by an intense ion beam. For larger cuts, the gap is crossed by an intense relativistic electron beam, stopped by magnetic bremsstrahlung resulting in a pointlike intense x-ray source. In either case, the impedance of the pinch discharge is increased, with the power delivered rising in the same pro-portion. A magnetically insulated cut is advantageous for three reasons: First, with the ion current com-parable to the Alfvèn ion current, the pinch instabilities are reduced. Second, with the energy deposit-ed into fast ions, a non-Maxwellian velocity distribution is established increasing〈σ ν〉 value for nuclear fusion reactions taking place in the pinch discharge. Third, in a high density z-pinch plasma, the intense ion beam can launch a thermonuclear detonation wave propagating along the pinch discharge channel. For larger cuts the soft x-rays produced by magnetic bremsstrahlung can be used to drive a thermonuclear hohlraum target. Finally, the proposed pulse power compression scheme permits to use a cheap low power d.c. source charging a magnetic storage coil delivering the magnetically stored energy to the pinch discharge load by an exploding wire opening switch.
Darkness Intensified -Existence of a Nonlinear Threshold in Redshift-Induced Dimming
Authors: Rössler O. E.
Published: February 2015

Redshift obeys adiabatic invariance. From this fact it follows that not only the individual photons are dimmed by a factor of z + 1 (if z is the redshift in percent), but the photon flux is reduced by the same factor once more. Hence the luminosity of any source is in the presence of redshift dimmed by a factor of (z+1)2. This model-independent result possibly “explains away” the excess dimming of strongly redshifted Type-la super-novae, discovered in 1998.
Electrohydrodynamic Interfacial Stability Conditions in the Presence of Heat and Mass Transfer and Oblique Electric Fields
Authors: El-Sayed Mohamed Fahmy
Published: February 2015

A novel mathematical formulation to deal with interfacial stability problems of the Kelvin-Helmholtz type with heat and mass transfer in the presence of oblique electric fields is presented. The perturbed system is composed of two homogeneous, inviscid, incompressible, dielectric, and streaming fluids sep-arated by a horizontal interface, and bounded by two rigid planes. The effect of a phase transition on the instability is considered, and the linear dispersion relations are obtained and discussed. It is found that the electric field has a major effect and can be chosen to stabilize or destabilize the flow. For Ray-leigh-Taylor instability problems of a liquid-vapor system it is found that the effect of mass and heat transfer enhances the stability of the system when the vapor is hotter than the liquid, although the clas-sical stability criterion is still valid. For Kelvin-Helmholtz instability problems, however, the classical stability criterion is found to be substantially modified due to the effects of the electric field, mass and heat transfer. A new stability condition relating the magnitude and orientation of the electric field and the dielectric constants is obtained. Oblique electric fields are found to have stabilizing effects which are reduced by the normal components of the electric fields. The effects of orientation of the electric fields and fluid depths on the stability configuration are also discussed.
Structure and Vibrational Spectra of the Vapour Molecules Fe2Cl6 and AlFeCl6
Authors: Akdeniz Z. , Tosi M. P.
Published: February 2015

54a,

Melting of aluminium and iron trichloride crystals is accompanied by a structural transition from octahedral to tetrahedral coordination of the metal ions, and a widely accepted interpretation of their liquid structure is that it mainly consists of strongly correlated dimeric units. Such Al2Cl6 and Fe2Cl6 molecules are stable in the vapour phase and coexist in gaseous mixtures together with AlFeCl6 molecules. In this work we extend to Fe2Cl6 and AlFeCl6 our earlier study of the ionic interactions in Al2Cl6 [Z. Akdeniz and M. P. Tosi, Z. Naturforsch. 180 (1999)], using a model which accounts for ionic deformability through (i) effective valences and (ii) electrostatic and overlap polarizabilities. The main disposable parameters of the model are adjusted to the Fe-Cl bond length in FeCl3 monomer molecule and to the Fe-Fe bond length and a bond-stretching frequency in the Fe2Cl6 molecule. The results are used to evaluate the structure of the AlFeCl6 molecule, which has so far only been inferred from the observed Raman spectrum in mixed vapours. Extensive comparisons with data on molecular vibrational frequencies are also presented for Fe2Cl6 and AlFeCl6.
A Contribution to the Study of Ternary Saturated Electrolyte Solutions
Authors: Eysseltová J. , Ebert M.
Published: February 2015

A quantity has been introduced, whose dependence on the composition along the branches of the solubility isotherms of ternary systems consisting of two salts with a common ion and water exhibits breaks, which can be explained by the introduction of a previously unobserved configuration of the ternary saturated solution. In the respective region, a saturated solution in a ternary system may undergo second-order phase transitions to achieve specific configurations that are not derived from the structure of the binary saturated solution of the particular solute. It is assumed that further study of this phenomenon could contribute to a better understanding of the processes occurring in concentrated electrolyte solutions.
Steady-state and Time-resolved Spectroscopic Studies of Benzanilides
Authors: Heldt Józef , Heldt Janina R. , Kamiński Jerzy
Published: February 2015

Steady-state and time-resolved spectroscopic studies of benzanilide (I) and jV-methylbenzanilide (II)

were performed at 298 and 77 K in various solvents. The results indicate that benzanilide fluorescence
in non-polar solvents at room temperature involves three independent modes of emission: F1 (LE) normal
fluorescence from the initially excited state S1 (LE) with λmax = 320 nm, F2´(PT) fluorescence from the proton transfer tautomer with λmax = 468 nm, F2″CT) fluorescence from the species where intramolecular charge transfer appears, with λmax = 510 nm. At 77 K in MCH a new fluorescence band, Fag, appears at λmax=415 nm instead of the F2(PT) and F2″CT) fluorescence. This new emission originates from benzanilide dipolar aggregates or cis-imidol dimers. The decay times of these emission modes are
different.

N-methylbenzanilide, dissolved in nonpopular and weakly polar solvents at room temperature and at
77 K, shows only two fluorescence modes, i.e., the normal and the charge-transfer emissions at 320 nm
and 520 nm, respectively. The fluorescence is deactivated with two decay times, 30 ps and 2.05 ns, in
MCH solution.
High Resolution Infrared Detection of O=PF in the Gas Phase
Authors: Paplewski P. , Bürger H. , Beckers H.
Published: February 2015

Short-lived phosphenous fluoride, 0=PF, has been made by flash pyrolysis of F2POPF2 in Ar at 1200°C and detected by gas phase IR spectroscopy. The υ1 band, υ0 = 1297.5372 cm-1 , has been studied with a resolution of 8 x 10-3 cm-1 , and about 1500 transitions have been assigned. These were fitted using a Watson-type Hamiltonian, σ = 1.5 x 10-3 cm-1 , to excited state parameters up to quartic centrifugal distortion constants. The υ2 band was located at 819.58 cm-1 . An extended set of ground state parameters was obtained by combining recently measured microwave transitions with ground state combination differences formed from υ1 transitions.

The experimental results are in perfect agreement with the matrix IR spectra, mw measurements and ab initio calculations but disagree with a recently claimed low resolution detection of OPF in the gas phase.
Trifluoroacetic Acid; r0 -Structure, Partial Substitution Structure and Deuterium Nuclear Quadrupole Coupling Studied by Molecular Beam Microwave Fourier Transform Spectroscopy and by ab initio Calculations
Authors: Antolinez S. , Alonso J. L , Dreizler H. , Sutter D. H.
Published: February 2015

We report the assignment and analysis of all stable monosubstituted isotopomers of trifluoroacetic acid. The 13C and 18O isotopomers were observed in natural abundance. The rotational constants and quartic centrifugal constants are presented. The rotational constants are used to derive a partial substitution structure and a complete ro structure for future comparison with the corresponding values in hydrogen bridged bimolecules containing trifluoroacetic acid as a subunit. The deuterium nuclear quadrupole coupling constants are derived from the hfs-splittings of low-J rotational transitions of the CF3COOD isotopomer. The results of ab initio quantum chemical calculations are presented, which were carried out to assist in the assignment of the rotational spectra of the isotopomers and for comparison with the experimental molecular parameters.
Dielectric Studies of Inter-and Intramolecular Motions in the Nematic and Isotropic Phases of 7CP5BOC
Authors: Urban Stanisław , Gestblom Bo , Dąbrowski Roman
Published: February 2015

The dielectric relaxation of 7CP5BOC (2-chloro-4-heptylphenly 4-pentylbicyclo-[2,2,2]octan-l-car-boxylate) in its isotropic and nematic phase has been studied. The substance has a negative dielectric anisotropy. The complex dielectric permittivity was measured in the frequency range 10 kHz -3 GHz with the aid of an impedance analyzer and a time domain spectroscopy (TDS) method. The relaxation time, activation enthalpy and dielectric increments, characterizing the rotation of the molecules about the principal inertia axes, were obtained. It was found that the relaxation process connected with rota-tions about the long axis can be split into two independent motions of molecular moieties around the
Electrochemical Impedance Spectroscopic Study on Eu 2+ and Sr 2+ Using Liquid Metal Cathodes in Molten Chlorides
Authors: Matsumiya Masahiko , Takagi Ryuzo
Published: February 2015

For the pyrochemical reprocessing of spent metallic nuclear fuels in molten salt baths it is important to investigate the behavior of the electrochemically negative elements Eu and Sr, which are significant fission products. Voltammetric and chronopotentiometric studies have shown that the reduction of Eu 2+ and Sr 2+ on liquid Pb cathodes in molten chloride baths at 1073 K follows the alloy formation reaction: Eu 2+ + 2e− + 3Pb → EuPb 3 and Sr 2+ + 2e− + 3Pb → SrPb 3 . In the present work these alloy formation reactions were studiedby electrochemical impedance spectroscopy. Analysis of the spectra showed that the electronic exchange of Eu 2+ /Eu and Sr 2+ /Sr is quasi-re-versible. Moreover, the experimental results allowed the determination of the kinetic parameters of EU 2+ /EU and Sr 2+ /Sr, the diffusion coefficients of these species in molten chloride baths, and also the diffusion layer thickness.
Dynamic Nuclear Polarization Studies of TANOL/water-glycerol Solutions
Authors: Sert İsmail , Sünnetçioǧlu M. Maral , Sungur Rıza , Bingöl Gökçe
Published: February 2015

Dynamic Nuclear Polarization (DNP) studies of TANOL/water-glycerol solutions were per-formed at 1.53 mT. The samples have either various water-glycerol ratios at constant concentration or various concentrations at a constant water-glycerol ratio. The low field EPR spectra were recorded, the DNP parameters(enhancement factors, coupling constant, leakage factor) were determined, electronic relaxation times were measured. Depending on the values obtained, the interactions between nuclei and electrons are discussed.
Molecular Motion and Crystal Structure of Solid Tetrapentylammonium Iodide
Authors: Szafrańska B. , Małuszyńska H. , Pająk Z.
Published: February 2015

The proton NMR spectra and spin-lattice relaxation times of tetrapentylammonium iodide have been measured between 100 K and the melting point. The room temperature crystal structure has been determined by X-ray diffraction as orthorhombic, space group Ccca, Z = 4 with a = 10.811(2), b = 22.771(5) and c = 9.500(2) Å with fully ordered tetrapentylammonium cations. The existence of a solid-solid phase transition at 400 K has been confirmed by DTA. The onset of C 3 methyl group reorientations characterized by Arrhenius activation parameters has been evidenced. The intracation conformational motions in the pentyl chains start to manifest themselves already at lower temperatures. The appearence of an ionic plastic phase with coexisting liquid-like and solid-like cations has been discovered.