bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Observation of Decoherence with a Movable Mirror
Authors: Folman R. , Schmiedmayer J. , Ritsch H. , Vitali D.
Published: February 2015

Recently it has been proposed to use parity as a measure of the mechanism behind decoherence or the transformation from quantum to classical. Here, we show that the proposed experiment is more feasible than previously thought, as even an initial thermal state would exhibit the hypothesized symmetry breaking. - Pacs: 03.75.Be, 03.65.Nk
Entangled State Reconstruction of an Electron in the Penning Trap
Authors: Fortunato Mauro , Massini Michol , Mancini Stefano , Tombesi Paolo
Published: February 2015

We apply a tomographic method we have recently proposed to the reconstruction of the full entangled quantum state for the cyclotron and spin degrees of freedom of a trapped electron. Our numerical simulations show that the entangled state is accurately reconstructed. -Pacs: 03.65.
Evolution of an Atom Impeded by Measurement: The Quantum Zeno Effect
Authors: Wunderlich Chr. , Balzer Chr. , Toschek P. E.
Published: February 2015

A quantum system being observed evolves more slowly. This "quantum Zeno effect" is reviewed with respect to a previous attempt of demonstration, and to subsequent criticism of the significance of the findings. A recent experiment on an individual cold trapped ion has been capable of revealing the micro-state of this quantum system, such that the effect of measurement is indeed discriminated from dephasing of the quantum state by either the meter or the environment.
Laser Assisted Cherenkov Emission in Resonant Media
Authors: Artoni M. , Carusotto I. , Rocca G. C. La , Bassani F.
Published: February 2015

We theoretically examine the behaviour of Cherenkov radiation in a lossy, dispersive and resonant medium when emission is assisted by an external electromagnetic field. Under the appropriate coherence conditions for Cherenkov emission, we anticipate a large increase of the emission yield at resonance. Our predictions are implemented by numerical estimates for cuprous oxide (Cu20 ). Pacs: 61.43.Fs, 77.22.Ch, 75.50.Lk
Transverse Momentum Distribution of Atoms in an Interferometer
Authors: Božić Mirijana , Arsenović Dušan , Vušković Lepša
Published: February 2015

From the stationary solution of Schrödinger's equation in an interferometer we derive the wave functions of the longitudinal and the transverse motion. The former function is a plane wave. The wave function of the transverse motion is a one dimensional wave packet representing a super­ position of components with various values of the particles transverse momentum. The particles transverse momentum distribution in an interferometer is time independent and is determined by the aperture wave function. Consequently, it is independent of the distance from the slits. As such, it is a very important characteristic of the quantum state. Experimental determination of the mo­ mentum distribution would support the particle and wave interpretation of quantum interference in a new manner.
Local Realistic Theory for PDC Experiments Based on the Wigner Formalism
Authors: Casado Alberto , Risco-Delgado Ramón , Santos Emilio
Published: February 2015

In this article we present a local hidden variables model for all experiments involving photon pairs produced in parametric down conversion, based on the Wigner representation of the radiation field. A modification of the standard quantum theory of detection is made in order to give a local realistic explanation of the counting rates in photodetectors. This model involves the existence of a real zeropoint field, such that the vacumm level of radiation lies below the threshold of the detectors.
Coherently Driven Micromaser Pumped by Atoms in Superposition States
Authors: Casagrande F. , Lulli A. , Santagostino V.
Published: February 2015

By a Monte Carlo wave function approach we describe the dynamics of a coherently driven micromaser pumped by coherently prepared atoms. The system can exhibit nonclassical effects such as quadrature squeezing, sub-Poissonian photonstatistics, and Rabi oscillations revival. The interplay between driving field and polarised atoms allows manipulating both the photon number and the phase of the cavity field. By varying either the atomic transit time or the injected field intensity, the coherence of the system dynamics can be enhanced or even suppressed, whereas the induced cavity field phase can be shifted.
A Coherent Approach to Spacetime Foam
Authors: Garattini R.
Published: February 2015

A coherent superposition of N Schwarzschild wormholes is proposed as a model for space­ time foam. Following the subtraction procedure for manifolds with boundaries, we calculate by variational methods the Casimir energy. A proposal for an alternative foamy model formed by N
Delayed-choice Measurement and Temporal Nonlocality
Authors: Kim Ilki , Mahler Günter
Published: February 2015

We study for a composite quantum system with a quantum Turing architecture the temporal non-locality of quantum mechanics by using the temporal Bell inequality, which will be derived for a discretized network dynamics by identifying the subsystem indices with (discrete) parameter time. However, the direct “observation” of the quantum system will lead to no violation of the temporal Bell inequality and to consistent histories of any subsystem. Its violation can be demonstrated, though, for a delayedchoice measurement
Chaos and Possible Underpinnings for Quantum Mechanics
Authors: McHarris Wm. C.
Published: February 2015

Deterministic chaos with its nonlinearities can formally reproduce some of the counterintuitive idiosyncrasies of quantum mechanics. In this paper I raise the question as to whether chaos might possibly supply some of the “hidden variables” that have been sought as underpinnings at a deeper level of quantum mechanics
Brownian Motion: the Quantum Perspective
Authors: Vacchini Bassano
Published: February 2015

We briefly go through the problem of the quantum description of Brownian motion, concentrating on recent results about the connection between the dynamics of the particle and dynamic structure factor of the medium. - 05.40.Jc, 05.30.Fk, 05.30.Jp, 03.65.Yz
A Neutron and X-ray Diffraction Study of the Structure of Nd Phosphate Glasses
Authors: Hoppe Uwe , Ebendorff-Heidepriem Heike , Neuefeind Jörg , Bowron Daniel T.
Published: February 2015

Diffraction experiments were performed on two (Nd2O3)x(P2O5)1- x glasses for studying the en­ vironmental order of the Nd3+ cations. In case of the metaphosphate glass (x = 0.25) a combination of X-ray and neutron diffraction data was used to separate the Nd-O and O-O first neighbor peaks. An Nd-O coordination number of 6.6±0.3 and a mean Nd-O distance of (0.239±0.001) nm were determined. In the ultraphosphate glass studied (x = 0.20) these values increase to 6.9±0.3 and (0.240±0.001) nm where the Nd-0 coordination number is equal to the number of terminal oxygen atoms (OT) which are available for coordination of each Nd3+ cation. This indicates the formation of NdOn polyhedra not sharing any O atom where also all OT's are in N d-OT-P positions. In the metaphosphate glass the NdOn polyhedra have to share some OT sites.
Phase Transitions and Water Dynamics of [Co(H2O)6](ClO4)2 and [Mn(H2O)6](BF4)2 Studied by Neutron Scattering Methods
Authors: Mikuli E. , Migdał-Mikuli A. , Natkaniec I. , Grad B.
Published: February 2015

Inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) patterns, registered for [Co(H2O)6](ClO4)2 at 18 -270 K and for [Mn(H2O)6](BF4)2 at 18 -230 K, provided evidence that these crystals possess three solid phases in these ranges of temperatures. In both compounds the phase transition occurring at TC3 is connected with a change of the crystal structure, and that occurring at TC2 with a change in the rate of the reorientational motions of H2O ligands.
Mössbauer Investigation of Eu3+ Site Occupancy and Eu-O Covalency in Y2O3 and Gd2O3 Nanocrystals
Authors: Concas G. , Muntoni C. , Spano G. , Bettinelli M. , Speghini A.
Published: February 2015

Samples of nanocrystalline Y1.8Eu0.2O3 and Gd1.8Eu0.2O3 were examined by 151Eu Mössbauer spectroscopy. The degree of covalency of the Eu-O bond has been studied. The spectrum of the cubic Y1.8Eu0.2O3 sample has been resolved into 2 contributions due to europium in the C3i and C2 sites, for the first time in 151Eu Mössbauer spectroscopy. The degree of covalency and the electric field gradient of the 2 sites has been compared. The occupancy, by the lanthanide ion, of the more and less symmetric sites in the cubic structure of Y1.8Eu0.2O3 has been investigated and discussed.
Molecular Dynamics Simulation of the Internal Mobilities in Molten (Dy1/3,K)Cl
Authors: Matsumiya Masahiko , Takagi Ryuzo
Published: February 2015

Molecular dynamics simulations have been performed on molten (Dy1/3,K)Cl at 1093 K in order to compare the calculated self-exchange velocity (SEV), self-diffusion coefficient (D) and electrical con­ductivity with the corresponding experimental results. It was found that SEV, v, and D of potassium de­ crease with increasing concentration of dysprosium, as expected from the internal mobility, b. The decrease of bK, vK, and DK are ascribed to the tranquilization effect by Dy3+ which strongly inter­ acts with CP. On the contrary, bDy, vDy, and DDy increase with increasing concentration of Dy3+. This may be attributed to the stronger association of Dy3+ with Cl- due to the enhanced charge asym­ metry of the two cations neighboring to the Cl-. In addition, the sequence of the calculated SEV's, D's and electrical conductivities for the various compositions were consistent with those of the referred ex­ perimental results.
Nematogenic Behaviour of a Cyano-Compound Using Quantum Mechanics and Computer Simulations
Authors: Ojha Durga Prasad
Published: February 2015

Using quantum mechanics and intermolecular forces, the molecular ordering of a nematogenic cya-no-compound, 5-(frans-4-ethylcyclohexyl)-2-(4-cyanophenyl)-pyrimidine (ECCPP), has been exam­ ined. The CNDO/2 method has been employed to evaluate the net atomic charge and the dipole mo­ ment components at each atomic centre of the molecule. The configuration energy has been computed using the modified Rayleigh-Schrödinger perturbation method at intervals of 1Ä in translation and 10P in rotations, and corresponding probabilities have been calculated using Maxwell-Boltzmann statistics. The flexibility of various configurations has been studied in terms of the variation of the probability due to small departures from the most probable configuration. All possible geometrical arrangements between a molecular pair have been considered during stacking, in-plane and terminal interactions, and the most favourable configuration of pairing has been obtained. An attempt has been made to under­ stand the behaviour of the molecules in terms of their relative order. The results have been compared with those obtained for other nematogens like DPAB [4,4'-di-n-propoxy-azoxybenzene] and EMBAC [ethyl 4-(4'-methoxybenzylidene amino) cinnamate].
Sub-Doppler Measurements and Terahertz Rotational Spectrum of 12C18O
Authors: Klapper G. , Lewen F. , Gendriesch R. , Belov S. P. , Winnewisser G.
Published: February 2015

The five lowest rotational transitions of 12C180 (J =2 ← 1 to J = 6 ← 5) have been measured by saturation dip spectroscopy with an experimental accuracy of 1 to 1.5 kHz, employing phase-stabilized backward-wave oscillators. The five J rotational transitions cover the frequency range between 219 and 658 GHz. In addition, we have measured in the Doppler limited mode the rotational transitions J = 1 ← 0, J = 7 ← 6 and J = 8 ← 7. The accuracy achieved for the individual frequencies ranges between 5 and 20 kHz. Moreover the three rotational transitions J = 16 ← 15 to J = 18 ← 17 in the frequency region 1.7-2.0 THz were measured with an accuracy of 15 to 30 kHz by using the Cologne side­ band spectrometer for terahertz applications COSSTA.
Erratum
Authors: Bhatia P. K. , Bhadauria B. S.
Published: February 2015

The key words are: Rayleigh Number; Stability; Convection; Modulation. Equation (2.11a) must be read:
The Energy of a Graph and its Size Dependence. An Improved Monte Carlo Approach
Authors: Fripertinger Harald , Gutman Ivan , Kerber Adalbert , Kohnertb Axel , Vidović Dusica
Published: February 2015

In an earlier work [Gutman et al., Chem. Phys. Lett. 297, 428 (1998)] the average energy (E) of graphs with n vertices and m edges was examined, in particular its dependence on n and m . The quantity (E) was computed from a set of randomly, but not uniformly, constructed (n ,m)-graphs. We have now improved our method by constructing the (n,m)-graphs uniformly, so that every (n , m)-graph has equal probability to be generated. Differences between the old and new approaches are significant only in the case of graphs with a small number of edges.
Nematogenic Behaviour of EPPV in a Dielectric Medium. A Theoretical Study
Authors: Ojha Durga Prasad
Published: February 2015

4-(4/-ethoxyphenylazo) phenyl valerate (EPPV) is a nematic liquid crystal, which shows a nematic mesophase at 352 K and becomes an isotropic melt at 401 K. A theoretical study of the molecular order­ ing has been carried out on the basis of intermolecular interaction energy calculations. The CNDO/2 method has been employed to compute the net atomic charge and atomic dipole components at each atom­ ic centre of the molecule. Modified Rayleigh-Schrödinger perturbation treatment has been employed to calculate the interaction energy between a molecular pair. The probability of the occurrence of a partic­ ular configuration in a dielectric medium has been calculated using the Maxwell-Boltzmann formula. The flexibility of various configurations has been studied in terms of the variation of the probability due to a small departure from the most probable configurations. On the basis of stacking, in-plane and terminal interactions, all possible geometrical arrangements between a molecular pair have been considered, and the most favourable configuration of pairing has been obtained. An attempt has been made to explain the nematogenic behaviour of liquid crystals based on the parameters introduced in this paper.
Static and Dynamic Structure of Molecular Monomers and Dimers of the Rare-earth Fluorides
Authors: Akdeniz Z. , Gaune-Escard M . , Tosi M. P.
Published: February 2015

We determine a model of the ionic interactions in RF3 compounds, where R is a rare-earth element in the series from La to Lu, by an analysis of data on the bond length and the vibrational mode frequencies of the PrF3, GdF3 and HoF3 molecular monomers. All RF3 monomers are predicted to have a pyramidal shape, displaying a progressive flattening of the molecular shape in parallel with the lanthanide contraction of the bond length. The vibrational frequencies of all monomers are calculated, the results being in good agreement with the data from infrared studies of matrix-isolated molecules. We also evaluate the geometrical structure and the vibrational spectrum of the La2F6 and Ce2F6 dimers, as a further test of the proposed model. -PACS 36.40.Wa (Charged clusters)
Structural Studies on Substituted N-(phenyl)-2,2-DichIoroacetamides, 2/4-XC6H4 NHCO CHCI2 (X = H, Cl or CH3)
Authors: Gowda B. Thimme , Paulus Helmut , Fuess Hartmut
Published: February 2015

The effect of substitution in the phenyl ring on the crystal systems of amides of the type, 2/4-XC6H4-NHCO-CHCl2 (X = H, Cl or CH3), has been studied by determining the crystal structures of the compounds, iV-(phenyl)-2,2-dichloroacetamide, C6H5-NHCO-CHCl2 (PhDCA); N-(2-chlorophenyl)-2,2-dichloroacetamide, 2-ClC6H4-NHCO-CHCl2 (o-ClPhDCA), jY-(4-chlorophenyl)-2,2-dichloroacetamide, 4-ClC6H4-NHCO-CHCl2 (p-ClPhDCA) and N -(4-methylphenyl)-2,2-dichloroacetamide, 4-CH3C6H4-NHCO-CHCl2 (p-CH3PhDCA) and analysed the data along with our earlier crystal structures of the compounds, N-(phenyl)-2,2,2-trichloro-acetamide (PhTCA), N-(2-chlorophenyl)-2,2,2-trichloroacetamide (o-ClPhTCA), N -(4-chloro-phenyl)-2,2,2-trichloroacetamide (p-ClPhTCA), N-(4-methylphenyl)-2,2,2-trichloroacetamide (p-CH3PhTCA); N-chloro-N-(phenyl)-2,2-dichloroacetamide (NClPhDCA), N-chloro-N-(phenyl)-2,2,2-trichloroacetamide (NClPhTCA) and N-(phenyl) acetamide (PhA). The crystal type, space group, formula units and lattice constants in A of the new structures are; PhDCA: monoclinic, P 21/c, Z = 4, a = 8.785(3), b = 11.139(4), c = 9.521(3), ß = 97.47(2)°; o-CIPhDCA: monoclinic, P 21/c, Z = 4, a = 4.711(2), b = 11.234(6), c = 19.191(8), ß = 98.12(2)°; p-CIPhDCA: monoclinic, P 21/c, Z = 8, a = 18.627(5), b = 11.533(3), c = 9.583(3), ß = 102.43(2)°, and /?-CH3PhDCA: orthorhombic, Pbca, Z = 8, a = 9.464(3), b = 9.894(3), c = 21.973(7). The compound p-ClPhDCA shows two molecules in its asymmetric unit. This is in agreement with the multiple lines observed in the 35Cl NQR spectra of the compound. The crystal systems of the chlorosubstituted and methyl substituted chloroacetamides get interchanged on replacement of the side chain -CHCl2 by -CCl3. C(i)-C(j) ring distances show no significant variations with the substitution either at the side chain or in the phenyl ring. C(ring)-N and C (0)-N bond distances are also not much affected by either ring or side chain substitution, but are affected by N-chlorination, while the C -0 bond length is slightly shortened by the replacement of the -CH3 group by -CCl3, the introduction of electron withdrawing group into the phenyl ring or by N-chlorination. Deviations of C2(ring)-Cl(ring)-N, C6(ring)-Cl(ring)-N and C (ring)-N-C(0) bond angles from 120° narrow down on substitution either in the phenyl ring or in the side chain, but the latter increases on W-chlorination of the compounds.
Revisiting Julg's Structural Approach to Aromaticity
Authors: Giambiagi Myriam S. de , Giambiagi Mario , Figueiredo Aloysio Paiva de
Published: February 2015

Julg's classical formula for aromaticity is updated so as to involve bond indices. A simple CNDO/2 calculation is shown to account satisfactorily for heterocyclic typical rings and other mis­cellaneous systems. Results are compared with a multicenter MO bond index recently introduced as an aromaticity measure.
Magnetohydrodynamic Stability of Two Streaming Superposed Viscoelastic Conducting Fluids
Authors: El Mohamed Fahmy
Published: February 2015

The stability of the plane interface separating two Oldroydian viscoelastic superposed moving fluids of uniform densities when immersed in a uniform horizontal magnetic field has been in­ vestigated. The stability analysis has been carried out, for mathematical simplicity, for two highly viscous fluids of equal kinematic viscosities. It is found that the potentially stable configuration remains stable if the fluids are at rest, while it becomes unstable if the fluids move. The stability criterion is found to be independent of the viscosity and viscoelasticity, and to be dependent on the orientation of the magnetic field and the magnitudes of the fluids and Alfven velocities. It is also found that the potentially unstable configuration remains unstable in the absence of average fluid velocities, or in the presence of fluid velocities and absence of a magnetic field. The magnetic field is found to stabilize a certain wavenumbers range of the unstable configuration even in the presence of the effects of viscoelasticity. The behaviour of growth rates with respect to the stress relaxation time, strain retardation time, fluid and Alfven velocity parameters is examined analytically, and the stability conditions are obtained and discussed. -Pacs: 47.20.-k; 47.50.+d; 47.65.+a.
Media Effect upon the Fluorescence Ability of Differently Substituted α-Cyanostilbenes
Authors: Nikolov Peter , Petkova Irina , Stoyanov Stefan
Published: February 2015

The steady state and dynamic photophysical characteristics of α-cyanostilbene derivatives have been investigated in solution and in Polyvinylchloride (PVC) film at 300 K as well as in a frozen matrix at 77 K. While no emission is observed in solution, a significant fluorescence ability is registered both in PVC and frozen media. This fact is attributed to the matrix effect, which lessens the possible intramolecular motions around the central double bond. No phosphorescence at 77 K is observed. The fluorescence lifetimes at 77 K are compared with literature data for similar chemically fixed structures.
Electronic Spectral Investigations upon the Photochemical Transformations of Some Substituted 1-(N,N-bisacyl)amino-4,5-diphenyl-l,2,3-triazoles
Authors: Petkova Irina , Maroulis Apostolos J. , Hadjiantoniou-Maroulis Constantina , Nikolov Peter
Published: February 2015

The objective of this report is to investigate the steady state and dynamic photophysical and photochemical properties of 1-(N,N-bisacyl)amino-4,5-diphenyl-1,2,3-triazoles in solvents of dif­ferent polarity at room temperature and in frozen matrix at 77 K. On the basis of the comparison of their UV absorption and luminescence spectra with those of 4,5-diphenyl-1,2,3-triazole and diben-zamide (model compounds), cleavage of the N-N bond in the title compounds after irradiation with polychrome UV light is proved.
A Molecular Dynamics Simulation of the Electric and Thermodynamic Properties in Molten (Nd1/3, Na or K)Cl Mixtures
Authors: Matsumiya Masahiko , Takagi Ryuzo
Published: February 2015

Molecular dynamics simulations have been carried out on molten (Nd1/3, K)Cl at 1065 and 1073 K and (Nd1/3, Na)Cl at 1124 K for various compositions. The calculated self-exchange velocity (v ), self-diffusion coefficient (D), electrical conductivity (k) and enthalpy of mixing ( ΔHmix) were compared with the corresponding experimental values. The calculated results revealed that v and D of potassium decrease with increasing anmount of neodymium, as expected from the experimental internal mobility (6). The decrease of bK, vK, and DK are attributed to the tranquilization effect by Nd3+ which strongly interacts with Cl- as well as Dy3+. On the contrary, bNd, VNd, and DNd increase with increasing concentration of Nd3+. This might be ascribed to the stronger association of Nd3+ with Cl- due to the enhanced charge asymmetry of the two cations neighboring Cl- . In addition, the sequences of the calculated v's, D's and k ’s for the various compositions were consistent with those of the known experimental results. The experimental enthalpy of mixing with its negative dependence on the cation size was qualitatively reproduced.
Defect Structures for Fe3+, Mn2+, and Ni3+ Impurities in Wuritzite GaN Crystals
Authors: Zheng Wen-Chen , Wu Shao-Yi , Zi Jian
Published: February 2015

Electron paramagnetic resonance (EPR) zero-field splittings D for Mn2+ and Fe3+ in wurtzite GaN crystals are studied from high-order perturbation formulas based on the spin-orbit mechanism in both weak- and strong-field schemes. From these studies it can be seen that the Mn2+ or Fe3+ impurity does not occupy the exact Ga3+ position, but is displaced by ΔR on the C3 axis. The displacements are confirmed from a study of the superposition model, based on which a normal value of b̅2 (Ro) ( ≈ -0 .34 (15) cm-1 ) for the Fe3+-N3- combination is suggested. The EPR parameters D, g|| and g ⟂ for Ni3+ in GaN crystals are also studied. It is found that Ni3+ is almost not displaced. The impurity displacements in GaN are discussed by considering the valences and radii of these impurity ions and the replaced Ga3+ ion. - Pacs: 61.16Hn; 76.30Fc; 71.70Ch
An X-ray and Neutron Scattering Study of the Structure of Zinc Vanadate Glasses
Authors: Hoppe Uwe , Kranold Rainer , Gattef Emil , Neuefeind Jörg , Keen David A.
Published: February 2015

The short-range order of vitreous V20 5 and of three (Zn0)Jt(V20 5)1_x glasses with x = 0.2, 0.4, and 0.5 is studied by X-ray and neutron diffraction experiments where the change of the contrast allows to resolve the V -0 and Z n -0 correlations. The V -0 and the Z n -0 first-neighbor peaks are approximat­ ed by several Gaussian functions. In case of vitreous V20 5 two obvious V -0 distances exist which are related with V 0 4 and V 0 5 units. With ZnO additions the V -O coordination number decreases from 4.4 in vitreous V20 5 to 4.0 in the metavanadate glass where the strongest decrease of the fraction of V 0 5 units is found for glasses of * < 0.2. Dominantly, the V 0 5 groups are linked with the neighboring units by comers. The Z n-0 coordination numbers of the modified glasses are about five with closest dis­ tances of = 0.200 nm.
Frequencies and Normal Modes of Benz(a)anthracene. A MINDO/3-FORCES Treatment
Authors: Kubba Rehab M. , Shanshal Muthana
Published: February 2015

Quantum mechanical calculations, based on the MINDO/3-FORCES method, of the vibration fre­quencies and IR absorption intensities of benz(a)anthracene are reported and compared with calculated vibration frequencies of that molecule. For the first time a complete normal coordinate analysis for the molecule is reported. Interesting correlations between vibration motions of the same type but different symmetries are reported.
Vibration Frequencies and Normal Coordinates of Benzo(c)phenanthrene
Authors: Kubba Rehab M. , Shanshal Muthana
Published: February 2015

MINDO/3-FORCES quantum mechanical calculations yielded non-planar (C2) geometry of Ben-zo(c)phenanthrene. The result agrees with the majority of published results but disagrees with others in which a planar (C2 V) structure was accepted in order to simplify the analysis of certain spectroscopic data. Vibration frequencies and IR absorption intensities were calculated then, applying the non-planar (C2) structure. A complete normal coordinate analysis for the molecule is reported. Inspection of these coordinates allowed the discovery of some useful comparative relations between them, which are re­ ported in the paper.
Motions of Ethylammonium Ions in Solid Ethylammonium Chloranilate Studied by 1H Nuclear Magnetic Resonance
Authors: Ishida Hiroyuki , Kumagae Naoki , Sato Setsuko
Published: February 2015

The motions of the ethylammonium ion in solid ethylammonium chloranilate, C2H5NH+
3 • C6HO4CI-
2, are studied by 1H NMR second moment (M2) and spin-lattice relaxation time {T1) measurements. Re­ orientations of the CH3 group about the C-C bond axis and the NH+
3 group about C -N bond axis were observed and their motional parameters were evaluated. The internal rotational barriers of the CH3 and NH+
3 groups of an isolated C2H5NH+
3 ion were estimated from ab initio molecular orbital calculations.
Resonance Zones in Action Space
Authors: Wiersig Jan
Published: February 2015

The classical and quantum mechanics of isolated, nonlinear resonances in integrable systems with N ≥ 2 degrees of freedom is discussed in terms of geometry in the space of action vari­ ables. Energy surfaces and frequencies are calculated and graphically presented for invariant tori inside and outside the resonance zone. The quantum mechanical eigenvalues, computed in the sem iclassical WKB approximation, show a regular pattern when transformed into the action space of the associated symmetry reduced system: eigenvalues inside the resonance zone are arranged on iV-dimensional cubic lattices, whereas those outside are, in general, non-periodically distributed. However, TV-dimensional triclinic (skewed) lattices exist locally. Both kinds of lattices are joined smoothly across the classical separatrix surface. The statements are illustrated with the help of two and three coupled rotors. The energy-level statistics of this system are found numerically to be in very good agreement with the Poisson distribution, despite of the complex lattice structure. PACS: 03.65.Sq, 05.45.-a
Local Lattice Distortion near Co2+ in SrLaAlO4 Crystal
Authors: Wu Shao-Yi , Zheng Wen-Chen
Published: February 2015

The local tetragonal distortion in the vicinity of substitutional Co2+ impurities in SrLaAlO4 crystal is studied by fitting the calculated EPR parameters g\\, g⟂, A\\ and A⟂ to the observed values. The result shows that the local distortion is mainly due to the elongation of metal-ligand distance R± perpendicular to the C4 axis. This point is consistent with the expectation based on the consideration of ionic radius sum. This smaller tetragonal distortion of the oxygen octahedron surrounding the Co2+ impurity than that in the host crystal is supported by the result obtained in Cr3+-doped SrLaAlO4 crystal. -P a cs: 61.70Rj; 76.30Fc; 71.70Ch
Study of the Hydrogen Bond Network in sub-and supercritical Water by Molecular Dynamics Simulations
Authors: Krishtal S. , Kiselev M. , Puhovski Y. , Kerdcharoen T. , Hannongbua S. , Heinzinger K.
Published: February 2015

For 12 points along the tangent to the saturation curve at the critical point the temperature dependen­cies of the heights of the first maximum in the 0 -0 RDF, the average number of hydrogen bonds, and the self-diffusion coefficients have been calculated from MD simulations. The curves of these three properties show an inflection near the critical point. To improve the understanding of these changes in going from subcritical to supercritical water the librational spectra and the change in the fractions of wa­ter molecules with a given number of hydrogen bonds as a function of temperature have been derived from the simulations, additionally.
Nonlinear Waves 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 nonlinear propagation of waves on the surface of a fluid column in the presence of a magnetic field. The evolution of the amplitude is governed by a nonlinear Schrödinger equation which gives the criterion for modulational instability. Numerical results are given in graphical form
Three-dimensional Flow between Two Parallel Porous Plates with Heat Transfer
Authors: Singh K. D. , Sharma Rakesh
Published: February 2015

A theoretical analysis of the steady three-dimensional flow of a viscous, incompressible fluid between two parallel infinite porous horizontal plates is presented. The fluid is injected with constant velocity through the lower stationary plate and removed with a transverse sinusoidal suction velocity through the upper one in uniform horizontal motion. A series solution of the non-linear partial differential equations is obtained and discussed.
Mean Amplitudes of Vibration of BrO2F-
2 and IO2F-
2
Authors: Baran E. J.
Published: February 2015

Mean amplitudes of vibration of the anions BrO2F-
2 and IO2F-
2 have been calculated from vibrational spectroscopic data in the temperature range between 0 and 1000 K. Bond proper­ ties of these species are discussed on the basis of the obtained results and by comparison with known data for related mole­ cules and ions.
The Microwave Spectra of m-Xylene and m-Xylene-d10. Determination of the Low Methyl Internal Rotation Barrier
Authors: Thomsen C. , Dreizler H.
Published: February 2015

The rotational spectra of m-xylene, (CH3)2C6H4 and of m-xylene-d10, (CD3)2C6D4 have been recorded between 6 and 26.5 GHz using pulsed beam Fourier transform microwave spectroscopy. The clue for the assignment of the internal rotation multiplets was the inertial defect derived from the A1A1 species transitions.

The rotational constants for m-xylene and m-xylene-d10 are A = 3572.1117(1) MHz / 2896.1195(17) MHz, B = 1761.8621(1) MHz / 1446.0236(15) MHz, C =1197.3943(2) MHz / 988.2357(7) MHz, the barrier to internal rotation of the two methyl groups are V3 = 53.7(16) J/mol / 39.8(5) J/mol, their moments of inertia were assumed to be I∞= 3.14 uÅ2 / 6.28 uÅ2.
Thermodynamic Measurements on the Binary System Bis{[2,2-di(n- hexyloxycarbonyl)ethenyl]phenyl} Biphenyl-4,4'-dicarboxylate and 4-n-Octyloxyphenyl 4-n-Pentyloxybenzoate at Elevated Pressures
Authors: Würflinger Albert , Massalska-Arodż M. , Urbanb S. , Weissflog W. , Ernst S.
Published: February 2015

Thermodynamic measurements have been carried out on the binary system of a swallow-tailed liquid crystal A = bis{[2,2-di(n-hexyloxycarbonyl)ethenyl]phenyl} biphenyl-4,4'-dicarboxylate (4DS6) and B = 4-n-octyloxyphenyl 4-rc-pentyloxybenzoate (5O/O8). A filled smectic A phase is induced in the concentration range 0.11 < xA < 0.75. The maximum of the SmA-N transition temperature (365 K) is observed for xA
= 0.33. Dilatometric measurements show that the packing density in the filled phases is increased. High-pressure DTA is employed in order to investigate the coexistence range of the liquid crystalline phases and the slopes of the transition lines. The slopes of the melting curves for the mixtures are significantly smaller than those for the pure components. The slopes for the smectic - nematic - isotropic transitions are considerably larger. The coexistence range for the (smectic + nematic) phases does not seem to be pressure-limited, rather it increases with pressure.
Induced Smectic-G Phase through Intermolecular Hydrogen Bonding Part IX: Comparative Thermal and Phase Behaviour Studies on Two Distinct Structural Isomers Possessing Linear and Bow Shapes
Authors: Pisupati Swathi , Kumar P. A. , Pisipati V. G. K. M.
Published: February 2015

Two novel intermolecular hydrogen bonding mesogenic series comprising two distinct structural iso­ mers nABA:R:nABA and «ABA:H:«ABA (where R = resorcinol; H = hydroquinone; nABA = p-n-al-kyloxybenzoic acid with the alkyl carbon number varying from propyl-to decyl-and dodecyl-) have been synthesized using resorcinol and hydroquinone as central bent and linear cores, respectively. The thermal and phase behaviour of these complexes is studied by thermal microscopy and differential scan­ ning calorimetry. The IR spectral data confirm the formation of intermolecular hydrogen bonding between the OH group of the non-mesogen and -COOH group of the nABA moiety. Thermal studies reveal the existence of new phases: smectic-A and smectic-G. Comparative phase transition studies sug­gest that these isomers exhibit a different trend of mesomorphism.
27Al NMR Spectra of the RECl3-AlCl3 (RE = Y, La) Glasses and Melts
Authors: Zissi G. D. , Bessada C.
Published: February 2015

27 AI NMR spectra of pure crystalline and molten A1C13 and of RECI3-AICI3 (RE = Y, La) glass form­ ing binary mixtures have been obtained. Compositions corresponding mainly to YC13/A1C13 = 1/3 and LaCiyAlC^ = 1/3.7 have been studied from the glassy and crystalline state up to the melt. The 27A1 spectra can be unambiguously assigned to four-coordinated Al-species, such as A12C16, 'A1C14', and 'A12C17\ The chemical shifts lie between 95 and 110 ppm, very well separated with the -1.6 ppm giv­ en by the 'A1C16' coordination in solid A1C13. From the temperature evolution of the 27Al NMR spec­ tra, a description for the dynamic behaviour of these systems is proposed.
Influence of Ionic Liquids on Pd-Catalyzed Carbon-Carbon Bond Formation
Authors: Calò Vincenzo , Nacci Angelo
Published: February 2015

Rates of Heck-type reactions, catalysed by a Pd-catalyst with benzothiazole carbene as ligands, are strongly influenced by tetrabutylammonium bromide utilized as solvent.
Bessel Functions, Recursion and a Nonlinear Field Equation
Authors: Steeb Willi-Hans , Hardy Yorick , Stoop Ruedi
Published: February 2015

We show that particular solutions of certain nonlinear field equations can be constructed using Bäcklund transformations, recursion and Bessel functions.
The Interactions between Ta-Nb Ferroalloys and Sulfate-carbonate Melts
Authors: Chumarev V. , Krasikov S. , Timofeev M. , Savushkina O. , Maryevich V.
Published: February 2015

The reactions of pure metals Ta, Nb, V, Fe, Si, etc. and Ta-Nb-containing ferroalloys with sodium (calcium) sulfate (carbonate) melts are characterized by large exothermic effects and formation of solid, liquid and gaseous products. The liquid phases formed reduce diffusion restrictions and result in catastrophically large rates of metal oxidation.
Molecular Organization in a Nematogen: PBPCN -A Computational Analysis Based on Quantum Mechanics
Authors: Ojha Durga Prasad , Kumar Devesh , Pisipati V. G. K. M.
Published: February 2015

A computational analysis has been carried out to determine the configurational preference of a pair of 4'-n-pentyloxy-4-biphenylcarbonitrile (PBPCN) molecules with respect to translatory and orientational motions. The CNDO/2 method has been employed to evaluate the net atomic charge and atomic dipole components at each atomic centre of the molecule. Modified Rayleigh-Schrödinger perturbation theory along with multicentered-multipole expansion method has been employed to evaluate long-range intermolecular interactions, while a '6-exp' potential function has been assumed for short-range interactions. On the basis of stacking, in-plane and terminal interaction energy calculations, all possible geometrical arrangements of molecular pair have been considered. It has been observed that the molecule has a strong preference for stacking through a particular face, while the other configurations, such as stacking through the other face, in-plane and terminal interactions show, in general, an aligned structure along molecular axis. The results are discussed in the light of experimental as well as other theoretical observations.
Electrochemical Synthesis of Titanium Silicides from Molten Salts
Authors: Devyatkin S. V. , Boiko O. I. , Uskova N. N. , Kaptay G.
Published: February 2015

Presented at the NATO Advanced Study Institute, Kas, Turkey, May 4 -14, 2001. Electrochemical synthesis of titanium silicides from chloro-fluoride melts has been investigated by thermodynamic calculation, voltammetry and electrolysis. The electrochemical synthesis of four titanium silicides (TiSi2, TiSi, Ti5Si4, Ti5Si3) was to be a one-step process, the stoichiometry of the deposited silicides being correlated with the concentration of Si and Ti ions in the melt.
Redox Potentials of Samarium and Europium in Molten Lithium Chloride
Authors: Novoselova Alena , Shishkin Vladimir , Khokhlov Vladimir
Published: February 2015

The samarium (III)/(II) and europium (III)/(II) redox potentials in molten lithium chloride were measured using the direct potentiometric method in the temperature range from 923 to 1094 K. Glassy carbon was used as the indifferent working electrode, and the standard chlorine electrode as a reference. The total concentration of rare-earth chlorides dissolved in molten lithium chloride did not exceed 4.5 mol%.
Calculation of the CD Spectrum of Class A β-Lactamase from Escherichia coli (TEM-1)
Authors: Christov C. , Gabriel S. , Atanasov B. , Fleischhauer J.
Published: February 2015

The Circular Dichroism (CD) spectrum of β-lactamase from Escherichia coli (TEM-1) has been calculated with the matrix method on the basis of the x-ray diffraction structure. All known transitions in the peptide and side-chain groups, especially the aromatic and disulfide groups have been included. The calculations were performed with and without the tryptophan (Trp) residues. Rotational strengths calculated with the matrix method were combined with Gaussians to generate the CD spectrum. The calculated spectrum reproduces the signs and approximate magnitudes of the CD bands rather w ell only when the trytophan side chains are included. However, the experimental negative double band at 208 and 222 nm, which is characteristic for a-helices, is absent in the calculated spectrum.
Pressure Dependence of the Chlorine NQR in Three Solid Chloro Anisoles
Authors: Suresh K. S. , Ramesh K. P. , Rao C. Raghavendra , Ramakrishna J.
Published: February 2015

The 35C1 Nuclear Quadrupole Resonance (NQR) frequency (VQ) and spin lattice relaxation time (T1) in the three anisoles 2,3,4-trichloroanisole, 2,3,6-trichloroanisole and 3,5-dichloroanisole have been measured as a function of pressure upto 5.1 kbar at 300 K, and the data have been analysed to estimate the temperature coefficients of the NQR frequency at constant volume. All the three com­ pounds show a non linear variation of the NQR frequency with pressure, the rate of which is positive and decreases with increasing pressure. In case of 3,5-dichloroanisole the value becomes negative in the higher range of pressure studied. The spin lattice relaxation time T1 in all the three compounds shows a weak dependence on pressure, indicating that the relaxation is mainly due to the torsional motions.
Relaxation of 121Sb NQR in Antimony Trichloride due to Raman Process
Authors: Okubo Noriaki , Igarashi Mutsuo
Published: February 2015

The spin-lattice relaxation times of 121Sb nuclear quadrupole resonance in SbCl3 have been measured from 4.2 K to the m. p., 346 K. The result is analyzed with a theory of the Raman process based on co­ valency and discussed in comparison with the previous result for Cl nuclei.
Investigation of Structural Questions on Europium Compounds by Means of 151 Eu Mössbauer Spectroscopy
Authors: Concas Giorgio , Congiu Francesco , Spano Giorgio , Bettinelli Marco , Speghini Adolfo , Flint Colin D.
Published: February 2015

151 Eu Mössbauer spectroscopy permits the determination of the symmetry of the site in which Eu is accommodated. It has been shown that the 151Sm F3 source can be considered a monochromatic source. This source was used to measure the line width of Eu3+ in a site with cubic symmetry, i. e. in a Cs2NaEuCl6 crystal. The isomer shift of commercial compounds used as standards (anhydrous EuF3 and EuS) was also measured. In the case of Cs2NaEu(N O2)6 hexanitritoelpasolite the trivalent europium ion is accommodated in a site with perfect cubic symmetry. In Eu(PO3)3 crystalline metaphosphate, the rare earth is located in a site which appears to be distorted with respect to cubic symmetry; this site has no threefold or fourfold symmetry axis.
Unorthodox Thoughts about Deformation, Elasticity, and Stress
Authors: Koenemann Falk H.
Published: February 2015

The nature of elastic deformation is examined in the light of the potential theory. The concepts and mathematical treatment of elasticity and the choice of equilibrium conditions are adopted from the mechanics of discrete bodies, e. g., celestial mechanics; they are not applicable to a change of state. By nature, elastic deformation is energetically a Poisson problem since the buildup of an elastic potential implies a change of the energetic state in the sense of thermodynamics. In the Euler-Cauchy theory, elasticity is treated as a Laplace problem, implying that no change of state occurs, and there is no clue in the Euler-Cauchy approach that it was ever considered as one. The Euler-Cauchy theory of stress is incompatible with the potential theory and with the nature of the problem; it is therefore wrong. The key point in the understanding of elasticity is the elastic potential.
Thermodynamics of Lead(II) Halide Complex Formation in Calcium Nitrate Tetrahydrate -Acetamide Melts
Authors: Gadzuric S. B. , Zsigrai I. J. , Nikolic R. M.
Published: February 2015

The complex formation between lead(II) ions and chloride and bromide ions in melts of C a(N 03) 2 • 4 H2O • αCH3CONH2 has been studied at different temperatures between 30 and 70 °C. The formation constants of the complexes PbX+ and PbX2 (X = Cl, Br) were determined from em f measurements by means of Ag/AgX electrodes. The dependence of the formation constants for PbCl+ on the solvent melt composition has been analysed. The thermodynamic parameters ΔH0
11 and ΔS0
11 for PbX+ complex formation have been estimated. The parameters are compared with the literature data for the same process in dilute aqueous solutions and in some hydrated and anhydrous salt melts.
Thermodynamic Characteristics of Samarium and Europium Chlorides in Molten Alkali Metal Chlorides
Authors: Novoselova Alena , Khokhlov Vladimir , Shishkin Vladimir
Published: February 2015

The formal standard redox potentials of samarium (III)/(II) (E*Sm
3+/ Sm2+) and europium (III)/(II) (E*Eu3+ /Eu2+) in molten alkali metal chlorides were measured potentiometrically against a reference chlorine electrode. The Gibbs energy changes and equilibrium constants for the reaction LnCl2(I) + ½ Cl2(g) ⇔ LnCl3(I) were calculated for the salt systems studied. The effect of the cationic composition of the melt-solvent on the above thermodynamic characteristics is also reported.
Experimental and Theoretical Determination of Electronic State Energies of Naphthanilides
Authors: Brozis M. , Heldt J. R. , Heldt J.
Published: February 2015

Experimental absorption spectra of a -and β-naphthanilide derivatives in the vapour phase and in MCH solution are interpreted on basis of calculations performed using the INDO/S-CI method. The ground state geometries have been optimised with the PM3 parameterisation method. The calculated values of the lowest triplet state T1 as well as energy differences of the T1 → Tn transitions have been compared with measured data determined from the phosphorescence and picosecond transient absorption spectra. For SO → Sn and T1 → Tn transitions, a good agreement is noticed between the experimental and calculated energy values. An additional band observed in the total luminescence spectrum at 77 K, is interpreted as due to the emission of the double H-bonded imidol dimer formed in the excited state. -PACS: 31.70 Dk, 33.50 Dg
When is a Statistical Operator Separable? -A Comparison of Different Definitions
Authors: Krüger Thomas
Published: February 2015

Quantum correlations are based on the non-separability of the total system ’s statistical operator. The notion of non-separability, on the other hand, is given with respect to the precise meaning of separability only. So it is a crucial task to define separability in terms of statistical operators. A recently proposed approach offers several advantages with respect to the usual definition. The von Neumann entropy S allows to develop a measure Ia/b of the relative non-separability of an operator pa with respect to another operator pb. This is a system im manent quantity of any property type as, e. g. spin or polarization. We compare the effect of the different approaches on S and Ia/b- Finally, the applicability of a comm on separability criterion will be checked.
Mixing Enthalpies of TbBr3-MBr Liquid Mixtures
Authors: Rycerz L. , Gaune-Escard M.
Published: February 2015

The molar enthalpies of mixing, Δmix Hm in the binary liquid systems TbBr3-MBr (M = Li, Na, K, Rb, Cs) have been m easured with a Calvet-type high-tem perature microcalorimeter over the entire composition range with an accuracy of about 6 %. Mixing of the two liquid components was achieved by using the “break-off am poule” technique. All the investigated systems show negative enthalpies of mixing with a minim um value of approxim ately -1.25, - 8 .3 , -17.0, - 2 0 . 0 and -22.5 kJ mol -1, for M = Li, Na, K, Rb and Cs, respectively. The mixing enthalpy in the TbBr3- LiBr system is positive in the TbBr3-rich region. For all the systems, the enthalpy minimum occurs at mole fraction xTbBr3 ≈ 0.3 - 0.4. The molar enthalpies of form ation Δ formHm (3MBr, TbBr3, 1) for M = Li, Na, K, Rb and Cs at 1113 K (arising from the reaction 3M Br(1) +TbBr3(1) = (3MBr, TbBr3) (1)) are found to be -4 .8 , -31.3, -63.3, -70.3 and -8 1 .2 kJ mol-1 , respectively. The leastsquares coefficients A, B, C, D and E in the equation λ (kJ mol-1) = A + B x + C x2 + Dx3 + Ex4, where A is an interaction param eter and x = xTbBr , are also reported.
An Explanation of the Removal of Metastability in Some Hydroacid Salts by Water Adsorption
Authors: Baranowski B. , Lundén A.
Published: February 2015

The metastability of some phases of CsHSO4 and RbH2PO4 is due to the volume decrease at an endothermic phase transition which "locks in" the metastability in question. Water adsorption, which removes these metastabilities, probably exerts a "wedge-like" force which expands the lattice spacing in the surface layer, thus facilitating the start of the phase transition. The induction time and the zeroth order kinetics of the transition in RbH2PO4 are exponential functions of the water activity applied.