bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature Dependence of the Second Dielectric Virial Coefficients of Rare Gases
Authors: Bulanin M.O. , Hohm U. , Ladvishchenko Yu. M . , Kerl K .
Published: February 2015

Second dielectric virial coefficients Bε (T) of the rare gases Ne, Ar, Kr, and Xe are calculated in a broad range of temperature using accurate HFD-type interatomic interaction potentials and available information on the trace of the pair polarizability Δα. It is shown that the experimentally determined temperature-variation of Bε(T) cannot be reproduced by existing theories. However, it is observed that the reduced dimensionless form of Bε(T) follows a remarkably regular pattern, strongly resembling the sign-inverted temperature variation of the second density virial coefficient Bϱ(T) with the same Boyle-temperature.
Similarity Solutions of the Force-free Magnetic Field Equations
Authors: Richter E. W.
Published: February 2015

Force-free magnetic fields are described as solutions of special nonlinear partial differential equations which are replaced frequently through linear equations. To record the diversity of the structures of these fields, a discussion of the nonlinear equations is necessary. For this purpose the method of similarity analysis is used. The Lie symmetry groups admitted by the nonlinear equations for force-free magnetic fields are presented. To record and classify the different types of group-invariant solutions, one-and two-dimensional optimal systems of subalgebras are listed. The reduced equations of the two-dimensional optimal system are systems of ordinary differential equations, and their solutions define similarity solutions which are force-free magnetic fields. Only in one case is it necessary to calculate similarity solutions numerically. The corresponding reduced equations are a nonautonomous dynamical system with the similarity variable in the place of time.
Solomon Echoes Extended to Soft Pulse Excitation
Authors: Man Pascal P.
Published: February 2015

Solomon echoes, produced by two in-phase pulses separated by a delay τ2, are derived in taking into account the first-order quadrupolar interaction during the pulses. Consequently, the results are valid for any ratio of the quadrupolar coupling, ωQ, to the amplitude of the radiofrequency pulse, ωRF. Six echoes are predicted after the second pulse: three, detected as inner satellite signals, occur at τ4 = τ2, τ4 =2 τ2 and τ4 = 3 τ2/2; the other three, detected as outer satellite signals, occur at τ4=τ2/2, τ4 =τ2 , and τ4=3τ2/2. These echoes originate from the refocusing of single- and multi-quantum offresonance coherences developed during the first pulse. Four of them are allowed echoes, the other two are forbidden ones. However, there is no echo for the central transition. From a practical point of view this means that τ2 must be short compared to τFID, the duration of the FID of the central transition. The behavior of the echo amplitude versus the second pulse length is discussed for several ratios of ωQ/ωRF.
Calculation of Quadrupole Coupling Constants: From Gas to Liquid
Authors: Huber Hanspeter
Published: February 2015

Nuclear quadrupole coupling constants for D, 14N and 17O calculated with basis sets of high local quality are reviewed. It is confirmed that the concept of high local quality gives reliable results for many molecules in the gas phase. The calculations are extended to the condensed phase by combining quantum chemical calculations with molecular dynamics simulations. An excellent agree­ment with experiment is obtained for the deuterium coupling in liquid D2O and a fair agreement for 17O coupling in liquid H2
17O . The 21Ne nmr relaxation time in liquid neon is calculated to be within about 20% of experimental values, an exact comparison being difficult due to only roughly known pressures in the experiment and not adequately treated quantum effects in the simulations. Comparisons in the dense supercritical region at higher temperatures would be of interest, but experimental data are lacking.
Sternheimer Factors and Electric-Field-Gradient Hyperpolarisabilities for Ions in Crystals
Authors: Fowler P. W. , Kelly H. M.
Published: February 2015

Analytic coupled Hartree-Fock calculations of the electric field gradient response properties y (the Sternheimer shielding factor) and e (the dipole-dipole-electric field gradient hyperpolarisability) have been carried out on anions in clusters that simulate that crystal environment. The systems studied are F- in LiF and NaF, Cl- in LiCl and NaCl, O2-in MgO, S2- in MgS, and H- in LiH. Both properties show large reductions from free-ion values and significant variation with lattice parameter, and the results indicate that damped values of anion Sternheimer factors will be necessary in accurate simulation of N Q R data or modelling of properties of ion-pairs.
35Cl NQR Spin-Lattice Relaxation Mechanism in Ni(H2O)6SnCl6 and Mg(H2O)6SnCl6 Crystals
Authors: Horiuchi Keizo
Published: February 2015

The 35Cl NQR spin-lattice relaxation mechanism in isomorphous Ni(H2O)6SnCl6 and Mg(H2O)6SnCl6 crystals is reported. The spin-lattice relaxation time T1Q in the Ni compound is determined mainly by a paramagnetic relaxation. However, above ca. 400 K T1Q decreased rapidly and a log vs. T1 curve was almost linear. This steep decrease of T1Q was explained by reorientational motions of the anions with an activation energy of 73 kJ mol-1. In addition, a double minimum in T1Q, which can be interpreted as arising from the fluctuation o f the electric field gradient (EFG) at the chlorine site caused by cationic thermal motions, was observed around room temper ature. The temperature dependence of the 35Cl NQR T1Q in the Mg salt is re-analysed in the light of the EFG -modulation effect caused by a 180° flip motion of the H2O molecules and an overall reorientational motion of the [Mg(H2O)6]2+ octahedral cations as a whole.
Dynamics of Deuteron Glasses as Probed by 2 D Exchange NMR
Authors: Dolinšek J. , Zalar B. , Blinc R.
Published: February 2015

The deuteron intra-bond dynamics o f the deuteron glass phase in Rb0. 68(ND4)0.32D2AsO4 has been studied by 2 D exchange NMR which extends the NMR observation window from the kHz region into the milli-Hertz region. The results show that the O -D···O deuterons are indeed the basic reversible two-position dipoles in the structure and that deuteron intra-bond exchange -and thus dipole reversal transition -occurs deeply in the glass phase well below Tg where 1 D NMR techniques observe only frozen static glassy disorder.
17O Quadrupole Dips in Ammonium Persulphate
Authors: Peirson N. F. , Smith J. A. S. , Stephenson D.
Published: February 2015

The magnetic field dependence of the 1H spin-lattice relaxation time in ammonium persulphate shows pronounced minima near the 1H magnetic resonance frequencies of 1,200 and 2,200 kHz. These are interpreted in terms of a model involving cross-relaxation between 1H in the NH4 ion and 17O in natural abundance in the S2O2-
8 ions, the latter having a much shorter spin-lattice relaxation time. A theoretical analysis of the shape of the minima is used to derive values for the 17O quadrupole parameters. This analysis results in best estimate values for the quadrupole coupling constant of 6.75 (± 0.05) MHz and an asymmetry of 0.30 (± 0.02). Such values are indicative o f O-H hydrogen bonding and suggest the S2O2-
8 ion is not undergoing rapid reorientation at temperatures below 320 K.
Temperature Dependence of Impurity Induced EFG's in Extremely Diluted CuB
Authors: Sulzer G. , Ittermann B. , Diehl E. , Fischer B. , Frank H.-P. , Jäger E. , Seelinger W. , Stockmann H.-J. , Ackermann H.
Published: February 2015

The temperature dependence of impurity induced EFG 's around implanted 12B ions in Cu was measured for two lattice locations using the β-NMR method. The induced EFG at the nearest neighbouring host atoms decreases with increasing temperature for the case of 12B stopped on interstitial sites, whereas the opposite temperature behaviour was found if 12B is situated in substi­tutional sites.
Systematic Investigation of MF3 Crystalline Compounds (M = Al, Cr, Fe, Ga, In, Sc, Ti, and V) and Fe1-xMxF3 Mixed Series (M = Ga, Cr, V)
Authors: Blank H.-R. , Frank M. , Geiger M. , Greneche J.-M. , Ismaier M. , Kaltenhäuser M. , Kapp R. , Kreische W. , Leblanc M. , Lossen U. , Zapf B.
Published: February 2015

The electric field gradient at the fluorine site of several crystalline trifluorides was measured by means of the time differential perturbed angular distribution method. The hyperfine data (vQ and η) are systematically analyzed by taking into account the structural parameters of the crystals; they are also compared to the results obtained by point charge calculations.
Dehydration of Solid SnCl2(OH2)· H2O to SnCl2
Authors: Pirnat J. , Lužnik J. , Jagličić Z. , Trontelj Z.
Published: February 2015

The temperature and flow rate dependence of the dehydration of SnCl2(OH2) · H2O , having a layered structure, into SnCl2 in a dry inert gas stream is studied. The experimental results obtained via chlorine NQR and weight measurements are analysed in the light of the structural transformation of this compound. The mechanism of water depletion from the layered structure is discussed.
43Ca NMR Study of Bismuth-Based High-Tc Superconductors
Authors: Trokiner A. , Le Noc L. , Yakubovskii A. , Mykhalyov K.N. , Verkhovskii S.V.
Published: February 2015

As a first step of a study of the electronic properties of CuO2 planes by probing calcium nuclei in the bismuth-based high-Tc materials we report here the structural assignment of Ca NMR lines measured in 43Ca-enriched samples of n = 2 ((Bi,Pb)2Sr2CaCu2O8+x) and n = 3 ((Bi,Pb)2Sr2-Ca2Cu3O10+x) bismuth compounds. Powdered samples were investigated as well as oriented pow­ ders, achieved by uniaxial alignment of the grains in a 7T magnetic field. For the main calcium site (Ca between two CuO2 planes), we could determine the quadrupolar as well as the shift tensors. The results indicate that, in the same way as yttrium nuclei in YBaCuO, calcium nuclei are sensitive to the magnetic susceptibility of the metallic CuO2 planes.
Nuclear Quadrupole Resonance Study of Copper in Electron-Irradiated YBa2Cu3O6.95
Authors: Kieninger M. , Majer G. , Seeger A. , Dworschak F.
Published: February 2015

NQR of Cu in YBa2Cu3O6.95 was investigated before and after low-temperature electron irradiation as well as after annealing at several distinct temperatures up to 440 K. Irradiation with 2.76 MeV electrons (fluence ϕt = 2.2 · 1023 e-/m 2) decreased the critical temperature Tc from 91.8 K to 89.5 K. The NQR spectra indicate that the e- irradiation displaces so-called 0 (4) atoms in the Cu - O chains. It is argued that this results in a modification of the average valence of the Cu(2) atoms in the planes, which explains the reduction of Tc. Recovery of the radiation damage sets in (presumably due to the onset of mobility of displaced oxygen atoms) during annealing at 300 K but was still incomplete at 440 K.
Investigation of the Phase Transition at 67.17 K in the Thiourea-CCl4 Inclusion Compound. As Studied by 14N NQR
Authors: El Ghallali J. , Gourdji M. , Guibé L. , Péneau A.
Published: February 2015

The 14N NQR from the host lattice of the thiourea-carbon tetrachloride inclusion compound. From calorimetric measurements, two phase transitions are known to occur at 67.2 K and 41.3 K in this compound. Above the 67.2 K transition, the 14N NQR spectrum consists of one resonance, though a small splitting of about 0.5 kHz is seen at temperatures up to ca. 105 K. Below the transition, the resonance appears as a central component, in continuation of the resonance above the transition, and two satellites at + 10 kHz and -8 kHz from the central line. The transition from the single resonance to a fully resolved spectrum takes place in a temperature range of less than one kelvin. The results are compared with those previously obtained with the thiourea-cyclohexane inclusion compound.
Positronium Quadrupole Interactions in Crystals
Authors: Bondarev I.V. , Kuten S.A.
Published: February 2015

It is shown that, due to the hyperfine interaction between the electron and the positron, positronium atoms in a crystal can acquire an effective quadrupole moment and a tensor polarizability. In such a case the effective quadrupolar interaction with intracrystalline fields leads to a quadrupolar splitting of the triplet level of positronium and also to an anisotropy of its magnetic quenching in the presence of an external magnetic field. The possibilities of observating this anisotropy experimentally are discussed.
A Model Study of Electrical Impedance Tomography Using Synthetic Finite Precision Data
Authors: Buchert R. , Schilcher K.
Published: February 2015

We use a resistor network model for electrical impedance reconstruction from boundary data. On the basis of a particular choice of currents we construct a stable inversion algorithm.
Dissociation Degree of HSO-
4 and Mean Ionic Activity Coefficient of Aqueous Sulfuric Acid of Different Molalities up to 473 K and 975 bar
Authors: Bilal B. A. , Müller E.
Published: February 2015

The apparent formation constant and the dissociation degree of HSO-
4 in aqueous H2SO4 of the molalities 0.1, 0.5, and 1.0 m, as well as the real mean ionic coefficient have been calculated up to 473 K and 975 bar using the thermodynamic data reported by Holmes and Mesmer at saturation pressure and those given by the authors at higher pressure.
Coupled Bistable Chemical Systems - Experimental Realization of Boolean Functions Using a Simple Feedforward Net
Authors: Zeyer K.-P. , Dechert G. , Hohmann W. , Blittersdorf R. , Schneider F. W.
Published: February 2015

We use the BZ-reaction and the MBO-reaction to implement the Boolean functions AND, OR, NAND , and NOR by the coupling of three chemical reactors. The experimental setup is analogous to a simple neural feedforward network with two reactors serving as the input layer and one reactor as the output layer. Coupling between the input and output reactors is carried out through the flow rate (BZ- and MBO-reaction) and through the electrical current by the use of Pt working electrodes (BZ-reaction). The XOR- and XN OR functions may be realized with 5 reactors using combinations of the AND, NOR, NOR - and the AND, NOR, Or-chemical gates, respectively.
A Geometrical Model of the Structure of Liquid Silicon Incorporating the Local- and Medium-Range Orders
Authors: Ogawa Hiroshi , Waseda Yoshio
Published: February 2015

A new structure model of liquid silicon is tested by incorporating the local bond orientational order and the medium-range radial distribution. The shoulder observed on the high Q side of the principal peak in the structure factor of liquid silicon appears to be mainly caused by the atomic radial distribution in the range from 0.4 to 0.6 nm. On the other hand, a molecular dynamics simulation on liquid silicon shows that the angular distribution of neighboring atoms has tetrahedral-like features, similar to those in the β-tin type crystal structure with c/a = 0.7. With these facts in mind, a new geometrical model of liquid silicon is proposed which simultaneously satisfies the experimental density, radial distribution, calculated bond orientational order, and typical liquid nature of random orientation in the long range.
Statistical Mechanical Interpretation of Black Hole Entropy
Authors: Winterberg F.
Published: February 2015

It is shown that the Bekenstein-Hawking formula for the entropy of a black hole can be given a statistical mechanical interpretation in terms of Planck mass particles. It is furthermore shown that the previously proposed Planck aether model (assuming that space is densely filled with an equal number of positive and negative Planck masses) gives an expression for the black hole entropy, different from the Bekenstein-Hawking formula, with the entropy proportional to the 3/4 power of the black hole surface rather than proportional to its surface.

The Planck aether model also gives an expression for the entropy of the gravitational field, which for a black hole is the entropy of negative Planck masses. To be consistent with Nernst's theorem, it is conjectured that this gravitational field entropy is negative. For a universe in which the sum of the positive matter energy and the negative gravitational field energy is zero, the sum of the matter and gravitational field entropy would therefore vanish as well. Because the positive and negative Planck masses are separated from each other, a cancellation of their entropy appears to be only possible in the event of a gravitational collapse of the universe as a whole.
Konzept einer neuartigen Wärmekraftmaschine
Authors: Daniel H.
Published: February 2015

The Concept of a Novel Heat Engine The concept of a novel heat engine based on Knudsen-thermotransport of gas is outlined. The conversion factor is calculated. For small temperature differences its theoretical value amounts to half the Carnot value. The novel engine may turn out to be particularly suitable for using solar energy.
Wiener Number of Polyphenyls and Phenylenes
Authors: Gutman Ivan , Dömötör Gyula
Published: February 2015

It is shown that the values which the Wiener numbers of isomeric polyphenyls may assume are all congruent modulo 36. Similarly, the Wiener numbers of isomeric phenylens are always congruent modulo 18. These findings provide a rationalization for the known fact that the isomer-discriminating power of the Wiener number is rather weak. Extensions of the present results to more general classes of graphs are also pointed out.
Calculating the Determinant of the Adjacency Matrix and Counting Kekulé Structures in Circulenes
Authors: Gutman I. , Yeh Y.-N. , Lee S.-L. , Hosoya H. , Cyvin S. J.
Published: February 2015

The determinant of the adjacentcy matrix, the algebraic structure count and the Kekulé structure count of circulenes are shown to conform to simple expressions containing Fibonacci numbers.
Size-dependent Trends in the Scattering of Small Potassium Clusters by Water Molecules
Authors: Goldbach A. , Hensel F. , Rademann K.
Published: February 2015

Scattering o f small potassium clusters by water molecules has been studied in a molecular beam experiment for the first time. In the size range up to eight atom s, trends for cross sections have been obtained by investigating low energy collisions. Significant differences in relative cross sections can be assigned to inelastic collisions. As in case o f scattering o f sodium clusters by argon (Goerke, A. et al., J. Chem. Phys. 98, 9653 (1993)), rotational excitation of the clusters seems to be the dominating interaction.
Effective Gauge Theories with Symmetry Breaking
Authors: Grimm G.
Published: February 2015

In a previous paper a general group theoretical discussion of effective boson-fermion coupling theories (with com posite two-fermion bosons) resulting by weak mapping of nonlinear spinor-isospinor field models was given. In the present work these considerations are extended to the case of broken isospin symmetry and applied to a microscopic subfermion-description of phenomenolog­ical gauge theories with Higgs symmetry breaking.
Molecular Dynamics in the System Methanol-Dimethylsulphoxide
Authors: Ludwig R. , Zeidler M. D. , Farrar T. C.
Published: February 2015

NMR proton relaxation rates of normal and oxygen-17 enriched m ethanol-d3 in a mixture of 71 mol% methanol and 29 mol% dimethylsulphoxide-d6 (DMSO) were measured as a function of temperature between 298 and 158 K. From these data rotational correlation times of the methanol molecule in the mixture and the oxygen-proton dipolar spin-lattice coupling parameter were ob­tained. The latter parameter is considerably smaller than the one obtained from neutron diffraction studies of the molecular geometry of methanol. Additionally, deuteron and oxygen-17 relaxation rates were measured over the same temperature range. Using the rotational correlation times obtained from the oxygen-17 induced proton relaxation rates, the quadrupole coupling constant for deuterium was derived; it shows a temperature dependence. Application of the Poplett relation yielded the oxygen-17 quadrupole coupling constants, so that oxygen correlation times could be obtained. Comparison of deuteron and oxygen correlation times indicates that the reorientation of the methanol molecule in the methanol/DMSO mixture is anisotropic.
Phase Diagram,35Cl NQR,and Crystal Structure of 1-Chloro-2-methyl-2-chloromethylpropionic Acid(/β, β´-Dichloropivalic Acid),Phase II
Authors: Strauß Roman , Dou Shi-qi , Fuess Hartmut , Weiss Alarich
Published: February 2015

The phase diagram and the 35Cl NQR spectrum of (ClH2C)2(CH3)C -COOH have been studied in the temperature range 77 ≤ T/K ≤ melting point (343.8 K). On heating no phase transition appears. The cooling cycle shows strong undercooling of the melt, a phase transition at Tm → I = 319.9 K and a transition from the orientationally disordered phase I to the ordered phase II at TI → II = 297.2 K.

The 35Cl NQR spectrum is a doublet with negative temperature coefficients within the temperature range covered, showing no phase transition in the heating cycle. At 77 K (298 K) the frequencies are in MHz: γ1 = 34.830 (34.140); γ2 = 34.018 (33.258).

The ordered solid crystallizes in the space group Pbca, Z = 8, a = 1019.7 (3) pm, b = 1146.3 (3) pm, c = 1293.8 (3) pm. Phase I (plastic phase) is cubic face centered, a = 911 pm, Z = 4.
Application of a Miniaturised Probe for the Acquisition of Dielectric Data in Living Systems
Authors: Kohlsmann Stephan , Hetscher Matthias , Kramer Klaus
Published: February 2015

The complex permittivity ε* has been measured non-invasively in the cornea of two types of animal eyes and in erythrocyte suspensions in the frequency domain 1 ... 18,000 MHz. These measurements shall help to distinguish between eye diseases in a very early stage and to track the possible effect of “microthermics”, respectively. The analysis of the miniaturised probe used for the reflection method and the experimental set-up with its automatic scanning facility are presened.
The Rotational Spectrum of Tunnelling Methyl Groups
Authors: Clough S.
Published: February 2015

The quantum-classical transition of methyl rotation highlights conflicting assumptions of quan­tum and classical mechanics, the first assuming that identical fermions are indistinguishable while the second recognises they are distinguishable through their histories. When this is introduced into quantum mechanics, the two are compatible and there is a smooth transition of the methyl rotational spectrum with increasing temperature through the merger of three broadening peaks. The changing character of methyl dynamics through this transition is discussed.
Linear Scaling Laws in Bifurcations of Scalar Maps
Authors: Grebogi Celso
Published: February 2015

A global scaling property for bifurcation diagrams of periodic orbits of smooth scalar maps with both one and two dimensional parameter spaces is examined. It is argued that for both parameter spaces bifurcations within a periodic window of a given scalar map are well approximated by a linear transformation of the bifurcation diagram of a canonical map.
Entropic Characterisation of Diffusion
Authors: Stoop R. , Steeb W.-H.
Published: February 2015

The thermodynamic approach is applied for the description of normal and anomalous diffusion of one-dimensional maps on a grid of unit cells. The characteristic entropy functions are calculated. For the anomalous cases, the locations of the critical lines are determined.
Mass Selected ZEKE-Spectra of FeC2-Anions: A Spectroscopic Access to Intermediates in Catalytic Reactions of Hydrocarbons on Metal Surfaces
Authors: Drechsler G. , Bäßmann C. , Boesl U. , Schlag E. W.
Published: February 2015

Zero-kinetic-energy (ZEKE) photoelectron spectra of metalcarbide anions are presented, allowing a high resolu­tion spectroscopic access to intermediates in catalytic reac­tions of hydrocarbons on metal surfaces. As a first compound, FeC2 (an intermediate of the iron/acetylene system) has been chosen. Important for successful ZEKE spectroscopy was a special anion source and the selection by time-of-flight mass spectrometry. In addition, conventional laser induced photo­ detachment photoelectron spectroscopy in combination with our anion source and mass analyzer delivered valuable new information.
The rQ2-branch of HOOH at 1.05 THz
Authors: Krupnov A. F. , Belov S. P. , Winnewisser G. , Behrend J. , Liedtke M. , Schieder R. , Yamada K. M. T. , Herbst E.
Published: February 2015

The lower frequency rQ2-branch o f the torsional split rotational spectrum of HOOH has been recorded for the first time near 1.05 THz with Doppler limited resolution employing a Backward Wave Oscillator as the radiation source. The position of the Q-branch lines can be predicted very closely from a set of effective rotational constants derived individually for the two torsionally split levels. The symmetry of the molecule, and the height of the potential barrier against internal rotation, are the two main reasons for the clear separation between the rotational and torsional contributions to the spectrum of HOOH as well as the analogous molecule HSSH.
Light Propagation in a Curved-Space Friedmann Universe
Authors: Prokhovnik S. J. , Paparodopoulos A. E.
Published: February 2015

It was shown [1] that, in a Friedmann universe considered as an expanding ensemble of fundamental particles and whose 3-space is Euclidean, the propagation of light and its associated wavelength(s) partake in the expansion of the universe. In consequence, a light-signal emitted from any source will reach and pass every fundamental particle in its path at the same speed, c, despite the systematic mutual recession of any pair of such particles. This result, derived from the Robertson-Walker metric, is in full accord with all local physical experience of light transmission and with the requirements o f Einstein's Special Theory of Relativity. It is shown here that the same result also applies to any curved-space Friedmann universe.
Dilatometric Study of the Isotropic-Smectic F Transition of 10O.14
Authors: Rao N. V. S. , Padmaja Rani G. , Potukuchi D. M. , Pisipati V. G. K. M.
Published: February 2015

The compound N(p-n-decyloxy benzylidene)p-n-tetradecyl aniline, (10O.14), a higher hom ologue of the MBBA series, exhibits smectic F and smectic G phases. Dilatometric studies inferred strong pre-transitional effects in a large temperature range. DSC results confirmed the first order nature of the IF and FG transitions. The exponential growth of continuous six fold hexagonal order across the isotropic-smectic F phase transition is estimated from the density studies with an exponent b = 0.75.
Chaos Control and Neural Classification
Authors: Hoff Axel A.
Published: February 2015

Chaotic behaviour in biological neural networks is known from various experiments. The recent finding that it is possible to "control" chaotic systems may help answer the question whether chaos plays an active role in neutral information processing. It is demonstrated that a method for chaos control which was proposed by Pyragas can be used to let a chaotic system act like an autoassociative memory for time signal inputs. Specifically a combined chaotic and chaos control system can reconstruct unstable periodic orbits from incomplete information. The potential relevance of these findings for neural information processing is pointed out.
Radiation Induced Incorporation of CO in Pure and Aqueous Methanol
Authors: Jung Hak-Jin , Getoff Nikola , Lorbeer Eberhard
Published: February 2015

Pure and aqueous methanol were used for radiation induced incorporation of CO at elevated pressure (up to 15 bar). The initial yields (Gi) of the main products in pure methanol under 15 bar CO and 1 bar N2O were found to be: Gi(formaldehyde) = 3.80 and Gi(glycolic aldehyde) = 2.0. For aqueous (10-2 mol · dm-3) methanol under 15 bar CO (dose: 0.557 kGy, pH = 2): the yields were G(formaldehyde) = 5.44, G(glycolic aldehyde) = 4.0 and G(oxalic acid) = 7.7. At pH = 7 the yields were essentially lower, namely: G(formaldehyde) = 3.2, G(glycolic aldehyde) = 2.0, G(formate) = 3.8 and G(oxalate) = 5.0. Probable reaction-mechanisms for the product formation are discussed.
Notizen: New Concept of a Scanning Laser Microscope Integrated Inside an Encapsulated Cryogenic Sample Stage
Authors: Kittel A. , Willmann A. , Wener H.-G. , Richter R. , Huebener R. P. , Parisi J.
Published: February 2015

We introduce a compact scanning laser microscope that is applicable for direct visualization of dissipative electric structures in solid state systems. In order to overcome the disturbing influence of any background radiation, the shielded sample cryostage incorporates the complete microscope consisting of a laser diode, the deflection unit, and the focussing optics. Our imaging method provides access to a class of nonlinear transport phenomena that so far have eluded unperturbed observation.
Die Lösung der Schrödinger-Gleichung als eindimensionales Problem. I. Der Formalismus
Authors: Preuß H.
Published: February 2015

In this article a new method for solving the multi-dimensional Schrödinger-equation for electrons and nuclei will be discussed. It is shown by application of integral transformations and by use of space-filling curves how the multi-dimensional Schrödinger-equation can be replaced by an one­ dimensional integral equation. Furthermore the problems of accuracy arising due to the use of this approximative treatment are pointed out. The presented method can be stated without the Born-Oppenheimer approximation and the application of determinants for fitting the wave function is discussed in a new one-dimensional point of view.
Extended Lorenz Models and Time Dependent First Integrals
Authors: Steeb W.-H.
Published: February 2015

We show how computer algebra can be used to find time dependent first integrals of dissipative dynamical systems. Extended Lorenz models are studied as examples.
The Three-Center, χ-Electron Chemical Bond
Authors: Giambiagi Myriam S. de , Giambiagi Mario , Herrera Jorge
Published: February 2015

A definition is proposed for the number of χ electrons x involved in a three-center bond, based upon the corresponding two-center bond indices. The number of electrons is fractionary, ranging from about 1 to somewhat more than 4 in the systems considered here. It is seen that the sign of the three-center index does not depend on χ.
Investigation of the Structure of Amorphous Substances by Means of Electron Diffraction
Authors: Ankele Jürgen , Mayer Joachim , Lamparter Peter , Lamparter Peter , Steeb Siegfried
Published: February 2015

The structure factor of amorphous germanium was determined using 120 kV electrons, an Ω-filter for the elimination of inelastically scattered electrons and a correction procedure for multiple scattering. The structure factor thus obtained is in good accordance to that obtained with X-rays and neutrons, respectively.
Chloride Ion in Liquid Hydroxylamine: Pair Potential Function and Monte Carlo Simulation
Authors: Sompornpisut Pornthep , Kokpol Sirirat , Rode Bernd M.
Published: February 2015

An analytical pair potential function for the Cl--NH2OH interaction energy surface has been constructed based on basis set superposition error corrected ECP/DZP ab initio calculations. The potential has been tested by Monte Carlo simulation of a solution of one chloride ion in liquid hydroxylamine at 32 °C, leading to the conclusion that under these conditions Cl-forms a solvation shell of eight solvent molecules, coordinated via OH hydrogens.
Estimation of the Chemical Potential and the Activity of NaCl in Molten DyCl3-NaCl by Molecular Dynamics Simulation
Authors: Sakurai Masanori , Takagi Ryuzo , Adyaa Ashok K. , Gaune-Escard Marcelle
Published: February 2015

Molecular dynamics simulations of molten DyCl3-NaCl were carried out at liquidus temperatures of the phase diagram. The chemical potential and the activity of NaCl was successfully estimated with the method proposed by Powles et al., which requires only positional data of the ions at the temperatures in question.
Conjectured Breaking of the Superluminal Quantum Correlations By Turbulent Fluctuations of the Zero Point Vacuum Field
Authors: Winterberg F.
Published: February 2015

If the observed superluminal quantum correlations are disturbed by turbulent fluctuations of the ze-ro point vacuum energy field, with the turbulent energy spectrum assumed to obey the universal Kol-mogoroff law, a length is derived above which the correlations are conjectured to break. A directional dependence of this length would establish a preferred reference system at rest with the zero point ener-gy. Assuming that the degree of turbulence is given by the small anisotropy of the cosmic microwave background radiation, a length of ~60 km is derived above which the correlations would break.
Novel Morphology of Voids in Single-Quasicrystalline Icosahedral Al70.5Pd21.0Mn8.5
Authors: Waseda Y. , Suzuki S. , Urbanb K.
Published: February 2015

This paper deals with the morphology and surface chemistry of faceted voids existing in singlequasicrystalline icosahedral Al70.5Pd21.0Mn8.5. By observation with a scanning electron microscope of surfaces obtained by cleavage of the quasicrystal, the habit planes of the dodecahedral voids were identified. The chemical surface composition of the void surface was determined by Auger electron spectroscopy after cleavage in ultra-high vacuum.
Experimental Determination of Dipole Moments of Some Benzamide Derivatives
Authors: Heidt J. , Heidt J. R. , Raciniewskab M.
Published: February 2015

The excited state dipole moments of some benzamide derivatives are determined. The method of solvent induced shifts of electronic absorption bands in comparison with their positions in the gas phase is used. Some regular trends revealed in the obtained data are discussed. The present results are compared with those available in the literature.
High resolution spectroscopy of Ar-CH4 and Kr-CH4 in the 7 μ region (j = 1 ← 0 transition)
Authors: Paka I. , Roth D. A. , Heppa M. , Winnewisser G. , Scouterisc D. , Howard B. J. , Yamadad K. M. T.
Published: February 2015

Diode laser spectra of the rare gas - spherical top van der Waals complexes Ar-CH4 and Kr-CH4 were measured in the wavelength region near 1310 cm-1 and assigned. The most prominent lines of both complexes exhibit three dense but well resolved RP0, QR0, and RQ0 branches, correlated to the R(0) transition of the triply degenerate bending vibration v4 of methane, CH4. A model Hamiltonian based on Coriolis coupled states was applied for the assignment, analysis and fitting of the spectra to within the experimental accuracy of ≈ 15 MHz. The rotational B constants of the upper and lower states determined from the three allowed branches appeared to be strongly correlated. The precision in the determination of the rotational B constants of the two complexes was substantially increased by additional recording of several weak transitions in the nearly forbidden QP0 and RR0 branches, which were fitted together with the allowed transitions. The separation between the rare gas atom and the methane molecule in the ground vibrational state was determined to be 3.999 Å and 4.094 Å for Ar-CH4 and Kr-CH4, respectively. The measured small values of the splitting between the K=0 and the K = ±1 levels in the vibrationally excited state (0.39 cm-1 and 0.67 cm-1 for Ar-CH4 and Kr-CH4, respectively), which characterizes the anisotropy of the intermolecular potential, indicated that Kr-CH4 and Ar-CH4 together with Ne-SiH4 represent examples close to the free rotor limit, where the spherical top CH4 is almost free to rotate within the complex. In comparison, the previously analyzed Ar-SiH4 van der Waals molecule is closer to the hindered rotor limit.
NMR Study of Molecular Dynamics in a D ho Columnar Mesophase
Authors: Cruz C. , Sebastião P. J. , Figueirinhas J. , Ribeiro A. C. , Nguyen H. T. , Destrade C. , Noack F.
Published: February 2015

In this paper we report the first molecular dynamics study combining fast field-cycling and conven-tional NMR techniques in a thermotropic liquid crystal of discotic molecules exhibiting an ordered columnar hexagonal mesophase. Using the association of these techniques we obtained proton T1 data over a very large domain of Larmor frequencies (ω/2π from 500 Hz to 85 MHz). The proton spin-lattice relaxation results were analysed considering the structure of the mesophase and the types of movements which are expected to influence significantly the relaxation rate, namely local molecu-lar rotational reorientations, inter-columnar self-diffusion and collective movements corresponding to bending and compression of the columns. We verified that these mechanisms dominate the relaxation respectively for high, medium and low Larmor frequencies.
Notiz: Mean Amplitudes of Vibration of the Novel IF2-
5 Anion
Authors: Baran E. J.
Published: February 2015

Mean amplitudes of vibration for the recently described planar pentagonal IF2-
5 anion have been calculated, from vibrational spectroscopic data over a wide temperature range. The results are briefly discussed and some comparisons with related species are made.
Propagating Thermonuclear Burn by Laser Ignition of a Dense Z-Pinch
Authors: Winterberg F.
Published: February 2015

A linear pinch discharge above the Pease-Braginskii current and stabilized by axial shear flow can radiatively collapse to high densities. A thermonuclear detonation wave can then be launched from one end of the discharge channel by ignition with a powerful laser pulse. Axial shear flow stabilization may be realized by injecting a fast moving jet along the pinch discharge channel, possibly in combination with a frozen DT fiber positioned on the pinch axis.
Effect of Finite Larmor Radius on the Rayleigh-Taylor Instability of Two Component Magnetized Rotating Plasma
Authors: Sharma P. K. , Chhajlani R. K.
Published: February 2015

The Rayleigh-Taylor (R-T) instability of two superposed plasmas, consisting of interacting ions and neutrals, in a horizontal magnetic field is investigated. The usual magnetohydrodynamic equations, including the permeability of the medium, are modified for finite Larmor radius (FLR) corrections. From the relevant linearized perturbation equations, using normal mode analysis, the dispersion relation for the two superposed fluids of different densities is derived. This relation shows that the growth rate unstability is reduced due to FLR corrections, rotation and the presence of neutrals. The horizontal magnetic field plays no role in the R-T instability. The R-T instability is discussed for various simplified configurations. It remains unaffected by the permeability of the porous medium, presence of neutral particles and rotation. The effect of different factors on the growth rate of R-T instability is investigated using numerical analysis. Corresponding graphs are plotted for showing the effect of these factors on the growth of the R-T instability.
EPR Study of the Dynamic Jahn-Teller Effect of Cu2+ in CdBa(HCOO)4 · 2H2O Single Crystals
Authors: Kalkan Hüseyin , Atalay Sehriman , Senel Ismet
Published: February 2015

Electron Paramagnetic Resonance spectra of Cu2+ doped into cadmium barium formate dihydrate single crystal were studied at 300 K. The powder spectrum of this material was studied at 300 to 133 K. The values of the g and A hyperfine tensors were found to be temperature dependent. The temperature dependence of the Cu2+ EPR spectrum is discussed in terms of the dynamic Jahn-Teller effect. The angular variation of the spectra indicates the substitution of the host Cd2+ with Cu2+ . The spectra were fitted with a tetragonal spin-Hamiltonian, the parameters of which were determined at 300 K. The ground-state wave function of the copper complex has been constructed at 113 K and 300 K.
EPR of O2
- Radicals in the Zeolites NH4NaY and NH4CaA
Authors: Köksal F. , Ucun F.
Published: February 2015

Activated and non-activated states of the zeolites NH4NaY and NH4CaA, and their NH4 forms were prepared with an (NH4)2SO4 solution and were investigated by EPR after 7-irradiation. The formed radicals were attributed to O2
- supposed to be trapped near a trigonally coordinated framework of 27Al (I = 5/2). Anisotropic O2
- spectra were observed, consisting of hyperfine structure due to the 27Al framework, even at room temperature. This was attributed to the scarceness of NH4 sites or trap sites because of the preparation of the NH 4 forms of the zeolites with an (NH4)2SO4 solution. The crystal field splittings were found and interpreted.
Excitation of the 210 nm Zn II Line in a Hollow Cathode He-Ne-Zn Discharge
Authors: Jánossy M. , Mezei P.
Published: February 2015

In a hollow cathode He-Zn discharge it was observed that addition of Ne stops laser oscillation at the 492.4 nm Zn II line and increases significantly the spontaneous intensity at the 210 nm Zn II line, which originates from the 4d2 D5/2 lower level of the laser transition. Based on a rate equation model, the cross-section of the Ne ion-Zn atom charge transfer collisions populating the 4d2D5/2 level was determined. The cross-section 3.5x 10-15 cm2 found by us is in acceptable agreement with the value 2.3x 10-15 cm2 reported in the literature. This high cross-section together with existing lower level depopulation points to the possibility of obtaining laser oscillation at 210 nm in a Ne-Zn discharge.
13CP/MAS NMR Study of Motion and Local Structure of Phenethyl- ammonium Ion in [C6H5CH2CH2 NH3]2PbX4(X = Cl, Br, I)
Authors: Ueda Takahiro , Shimizu Katsuyuki , Ohki Hiroshi , Okuda Tsutomu
Published: February 2015

Ionic motion and local structure of phenethylammonium ion (C6H5CH2CH2NH3+) in a series of phenethylammonium lead(II) halides, [C6H6CH2CH2NH3]2PbX4 (X = Cl, Br, I) were studied by means of 13C cross polarization/magic angle sample spinning (CP/MAS) NMR technique. Among the three salts, remarkable differences in the spectra were observed in the signals corresponding to the phenyl carbons. The peaks from C2, C3, C5, and C6 in the phenyl group were split into three for the chloride and into two for the bromide, although in the iodide those were observed as a single peak. Coalescence of those peaks, as well as line broadening were observed on heating. This indicated that peak split brings about disorder of the orientation in the phenyl group around the C1-C4 axis, suggesting to have three and two orientations for the chloride and the bromide, respectively. Above room temperature the phenyl group undergoes chemical exchange among these orientations, and at higher temperature, reorientation with a large amplitude takes place around its axis. The apparent activation energies of the reorientation of the phenyl group for the chloride and bromide were estimated from the temperature dependence of the linewidth of the resonance peaks to be about 24 kJ mol-1 , 25 kJ mol-1 , respectively, which is similar to in the iodide (25.0 kJ mol-1). Ab initio molecular orbital energy calculation was carried out to evaluate the potential barrier of the internal rotation of the phenyl group in a free phenethylammonium ion. The intramolecular interaction was evaluated to be 13.9 kJ mol-1 from the calculation, and the intermolecular interaction results to be 10 kJ mol-1 .
Solid State Reaction Study of the System Li2CO3/Fe2O3
Authors: Berbenni V. , Marini A. , Capsoni D.
Published: February 2015

A thermoanalytical (TGA/DSC) and diffractometric (XRD) study has been performed on the solid state reaction system Li2CO3 -Fe2O3 in the x Li range 0.10±0.50. A detailed analysis of the results shows that the data are in agreement with a reaction model where the carbonate decomposition is regulated by the formation of both LiFeO2 and LiFe5O8 , and the relative amount of the two phases depends on the initial composition. The DSC evidence offers the possibility to directly quantify the LiFe5Ox phase. Furthermore it allows one to obtain the enthalpies of formation of both LiFeO2 and LiFe5O8 .
Field-Swept NMR Spectra of 11B in Pyrex Glass and 93Nb in NbN Perturbed by Quadrupole Interaction
Authors: Yoshida H. , Nishihara H. , Yokota S. , Ohyanagi M. , Nakaoki T.
Published: February 2015

NMR experiments of 11B by both field-swept and high-resolution NMR are reported to probe the electric field gradient at boron sites and its distribution in Pyrex glass. Both spectra are successfully interpreted with the same set of parameters. It is stressed that field-swept NMR experiments to observe total powder spectrum can be helpful to get information on electric field gradients and asymmetry pa-rameters if there exist many nonequivalent sites of atoms, since satellite transitions are affected by the larger first-order quadrupole effect. Field-swept NMR of 93Nb in superconducting NbN powder, prepared by self-propagating high-temperature synthesis, is also reported. A very broad field-swept spectrum disturbed by quadrupole interaction has been observed. The spectrum is simulated by assuming distributions in electric field gradient and Knight shift at Nb sites. It is stressed that a combination of experiments at separated frequencies is important.
Powder Zeeman NQR Study on the Absorption Forms for Nuclear Spin 5/2
Authors: Ege O. , Nishijima S. , Kimura E. , Akiyama H. , Hamai S. , Negita H.
Published: February 2015

For nuclei which have a nuclear spin of 5/2 and exhibit a small asymmetry parameter of the electric field gradient (ƞ) at the nuclear site, line shapes of the Powder Zeeman NQR (PZNQR) spectra based on the transition between the energy levels m1 = ± 1/2 and ± 3/2 (the lower frequency line) were studied by means of computer simulations and experiments. (i) When an ƞvalue is very small (type 1; ƞ= 0), the line shape exhibits two shoulders like the style of the American football player. (ii) While an ƞvalue is small (type 2; 0 < ƞ< around 0.01) but not zero, the line shape has two small peaks which are symmetrically located on the shoulders, as in the case of the small ƞtype of spin 3/2. (iii) When an ƞvalue is not small (type 3; around 0.01 < ƞ), the line shape has two symmetrical dips in stead of the peaks, which are also similar to the case of not small ƞ type of spin 3/2. As the ƞvalue increases from around 0.01, the two dips grow and reach the maximum at the ƞvalue of 0.349, and then become smaller and obscure in the range of ƞlarger than 0.349.

The observations of PZNQR spectra were performed for several compounds including the 127I and/or 121Sb nuclei to estimate the ƞvalues, and gave the results as follows: very small for 127I (207.683 and 209.133 MHz, at 77 K) in Snl4; very small for 127I (176.496 and 177.438 MHz, at 77 K) in Gal3; small for 127I (265.102 MHz, at 77 K) in CH3I; 0.33 for 127I (247.69 MHz, at 77 K) in C2H5I; 0.27 for 121Sb (58.23 MHz, at 290 K) in SbCl3. The estimated ƞvalues were compared to those obtained from the frequencies of two NQR lines for spin 5/2. They were in good agreement with each other for the small region of ƞ, though somewhat large disagreements were seen in the cases of not small ƞvalues.
Nuclear Quadrupole Interaction at 187W(β-)187Re in Tungsten Compounds
Authors: Schmidt Pit , Soldner Torsten , Tröger Wolfgang , Ni Xinbo , Butz Tilman , Blaha Peter
Published: February 2015

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The nuclear quadrupole interaction at 187W(β-)187 Re was determined by time differential perturbed angular correlation in WC, WS2, WSe2, WSi2, and CaWO4 to be (at 300 K): vQ = 335.9(2), 1094.9(1), 10311), 1131,5( 1), and 1085.9( 1) MHz, respectively. The asymmetry parameter ƞwas zero in all cases. For WSe2 and CaWO4 the temperature dependence of the nculear quadrupole interaction was determined between 300 K and about 900 K. Ab initio calculations of electric field gradients, using the WIEN95-code, were carried out for WC, WS2, WSe2, and WSi2 at W-sites and Re-impurities, and for CaWO4 at W-sites. Good agreement with experimental data was found.