bluuebunny/crossref_metadata_2025 huggingface dataset:
From Poincare's Divergences to Quantum Mechanics with Broken Time Symmetry
Authors: Prigogine Ilya
Published: February 2015

We discuss the spectral property of unstable dynamical systems in both classical and quantum mechanics. An important class of unstable dynamical systems corresponds to the Large Poincare Systems (LPS). Conventional perturbation technique leads then to divergences. We introduce methods for the elimination of Poincare divergences to obtain a solution of the spectral problem analytic in the coupling constant. To do so, we have to enlarge the class of permissible transformations, to include non-unitary transformations as well as to extend the Hilbert space. A simple example refers to the Friedrichs model, which was studied independently by George Sudarshan and his co-workers. However, our main interest is the irreducible representations in the Liouville space. In these representations the central quantity is the density matrix, and the eigenfunctions of the Liouville operator cannot be expressed in terms of the wave functions. We suggest that this situation corresponds to quantum chaos. Indeed, classical chaos does not mean that Newton's equation becomes "wrong" but that trajectories loose their operational meaning. Similarly, whenever we have an irreducible representation in the Liouville space this means that the wave function description looses its operational meaning. Additional statistical features appear. A simple example corresponds to persistent interactions in the scattering problem which cannot be treated in the frame of usual S-matrix theory.
Uncertainty Relation: From Inequality to Equality
Authors: Süssmann Georg
Published: February 2015

The uncertainty area δ (p, q): - [∫ W(p, q)2 dp dq] - 1 is proposed in place of δ p • δ q, and it is shown that each pure quantum state is a minimum uncertainty state in this sense: δ (p, q) = 2 π ħ. For mixed states, on the other hand, δ(p, q) > 2π ħ. In a phase space of 2F(=6N) dimensions, S: = k B • log[δF (p,q)/(2 π ħ)F] whit δF (p,q):= [∫ W(p, q)2 dF p dF q]-1 is considered as an alternative to von Neumann`s entropy S̃:= kB • trc [ρ̂ log (ρ̂-1)].
Quantum Irreversibility and Chaos
Authors: West Bruce J. , Grigolini Paolo , Bonci Luca , Roncaglia Roberto
Published: February 2015

Herein we establish a relation between quantum irreversibility and the chaotic semi-classical solutions for a spin-boson Hamiltonian system. We obtain quantum averages by numerically integrating the appropriate Liouville-Von Neumann equations of motion and find these averages to be less erratic than the corresponding chaotic semi-classical trajectories. However, the quantum averages are shown to be dissipative as measured by the entropy of the spin subsystem and to suppress the phenomenon of "revivals".
Understanding the q-Factors in Quantum Group Symmetry
Authors: Biedenharnf L. C. , Rao K. Srinivasa
Published: February 2015

A characteristic feature of quantum groups is the occurrence of q-factors (factors of the form qk, k ∈ ℝ), which implement braiding symmetry. We show how the q-factors in matrix elements of elementary q-tensor operators (for all Uq(n)) may be evaluated, without explicit calculation, directly from structural symmetry properties.
Rays and Phases: A Paradox?
Authors: Boya Louis J.
Published: February 2015

The states of a quantum mechanical system are represented by rays in Hilbert space, but interference phenomena, Berry phase, etc. make reference to vectors. We show how to solve this apparent paradox by appropriate use of the vector bundle structure of quantum theory.
The Quantum Phase
Authors: Kendrick B.
Published: February 2015

The geometrical nature of the quantum phase is introduced. This phase is shown to originate from the non-trivial geometry of the fiber bundle: Hilbert space → space of states. The analysis is performed working in the general non-adiabatic setting.
Poisson Brackets and Nijenhuis Tensor
Authors: Okubo Susumu
Published: February 2015

Many integrable models satisfy the zero Nijenhuis tensor condition. Although its application for discrete systems is then straightforward, there exist some complications to utilize the condition for continuous infinite dimensional models. A brief sketch of how we deal with the problem is explained with an application to a continuous Toda lattice.
Nonperturbative Behavior of Higher-Harmonic Production in a Model Atom
Authors: Becker W. , Long S. , Mclver J. K.
Published: February 2015

The emission of very high harmonics of a laser field irradiating a model atom defined by a three-dimensional delta function is considered and several nonperturbative features of the harmonic spectrum are discussed.
Detection of Laser Induced Gratings via Acoustic Enhancement
Authors: Black Truman D. , Larson Don A.
Published: February 2015

Using acoustic wave intermodulation, laser induced grating structures can be detected with enhanced sensitivity. Gratings with phase variations of the order of a few ^irad or displacement gratings of the order of 10 " 1 r m can be detected. The basic spatial frequency analysis explaining this detection enhancement is developed briefly in this paper.
The Dressed State Picture in Quantum Coherence and Interference
Authors: Keitel C.H. , Doss H . M . , Fleischhauer M. , Narducci L.M. , Scully M.O. , Zhu Shi-Yao
Published: February 2015

We investigate the advantageous description of driven multi-level systems in the dressed state representation. A demonstration is given for the cases of subnatural line narrowing and lasing without inversion.
Laser Linac Using a Lens Waveguide in Vacuum
Authors: Moore G. , Bochove E. , Scully M.O.
Published: February 2015

Acceleration of a relativistic electron beam by the longitudinal field component of a focused laser or microwave beam is optimal when the laser beam is radially polarized. The electron energy gain between focusing optical lenses with an arbitrary optical mode cannot greatly exceed that available from a Gaussian beam of the same power. Off-axis transverse forces focus and recollimate appropriately phased off-axis electrons over the acceleration length.
Sudarshan-Glauber P, Q, and Wigner W Distributions in Correlated-Spontaneous-Emission Lasers
Authors: Scully M.O. , Zhu Shi-Yao
Published: February 2015

A comparative study of Sudarshan-Glauber P, Q and Wigner distributions in correlated-spontaneous-emission lasers has been made. Immediately giving the information of squeezing by exam-ining the diffusion coefficients is the advantage of the Sudarshan-Glauber P representation.
Quantum Optics with Trapped Ions
Authors: Raizen M. G.
Published: February 2015

The ability to localize a small number of atoms, with each one moving much less than an optical wavelength (the Lamb-Dicke regime) is a prerequisite for a wide range of fundamental atom-field experiments. Recent developments in ion trapping technology, relevant to this goal, are discussed and some possible experimental directions are outlined.
Broken Chiral Symmetry in Hot QCD: The Pion Halo
Authors: Chang Ngee-Pong
Published: February 2015

The massless pion propagates in hot medium with an exponentially damped halo.
Self-Duality Condition and Critical Potentials
Authors: Cronström C. , Srivastava Prem P. , Tanaka K.
Published: February 2015

It is shown that the self-duality constraint on the scalar field (combined with the equations of motion) by itself leads to the critical forms for the potential that minimizes the energy functional in the Chern-Simons-Higgs (CSH) system. If we have only the Chern-Simons (CS) term in the SL (2, R) gauge group one obtains a formalism that yields the equations of motion of a variety on non-linear models in two dimensions when the curvature is set equal to zero.
Whither the Anyon ?
Authors: Hägen C. R.
Published: February 2015

It is pointed out that Chern-Simons field theories do not always allow an interpretation in terms of anyons even in the nonrelativistic limit. Significantly, when the two approaches are found to differ the former is the one which is compatible with established physical principles. Thus the role left for the anyon is that of a very special subcase of Chern-Simons theories in the limit in which relativistic and spin considerations become irrelevant.
Neutrinos: Harbingers of New Theories
Authors: Ramond P.
Published: February 2015

We catalog models with massive neutrinos, emphasizing their uses as probes of physics beyond the standard model. We discuss their experimental implications, in terms of neutrino oscillations and the MSW effect.
Planck Scale Physics and Newton's Ultimate Object Conjecture
Authors: Winterberg F.
Published: February 2015

According to Newton, the ultimate building blocks of matter are hard frictionless spheres. This conjecture is here analyzed under different assumptions, which are:

1. The ultimate objects of matter are frictionless positive and negative Planck mass particles obeying nonrelativistic Newtonian mechanics.

2. The Planck mass particles interact with the Planck force c 4 /G (c velocity of light, G Newton's constant) locally within a Planck length r p , with the positive Planck mass particles exerting a repulsive and the negative Planck mass particles an attractive force.

3. Space if filled with an equal number of positive and negative Planck mass particles, whereby in the average each Planck length volume occupies one Planck mass particle.

Making these three assumptions we derive:

1. Nonrelativistic quantum mechanics as an approximation with departures from this approxima-tion suppressed by the Planck length.

2. Lorentz invariance as a dynamic symmetry for energies small compared to the Plank energy.

3. The operator field equation for the previously proposed Planck aether model of a unified theory of elementary particles.

In contrast to theories in which the ultimate objects are strings at the Planck scale, the alternative theory proposed here does not need a higher dimensional space, but rather can be formulated in 3 + 1 dimensions.
NMR Study of Collective Motions and Bending Rigidity in Multilamellar System of Lipid and Surfactant Bilayers
Authors: Struppe J. , Noack F. , Klose G.
Published: February 2015

The frequency dependence of the longitudinal proton spin relaxation time T1 was measured by field-cycling and standard NMR techniques at different temperatures in the liquid crystalline lamellar phases of bilayer systems, composed of lipids, nonionic surfactants, and lipid-surfactant mixtures. We show by our data analysis, comparing various motional models such as layer undulations (LUs) and relaxation by translational diffusion mediated reorientations (TR), that collective layer undulations with their typical T1~ν behaviour determine the low frequency T1 dispersion in both unoriented and glass plate-oriented bilayer systems. The angular dependence of the T1 dispersion for the oriented bilayer system supports these findings and provides a more critical analysis of the two dimensional self-diffusion than in unoriented samples. The evaluated fitting parameters of the LU model allows, together with the measured second moment of the proton NMR signal for the lipid, calculation of the bending rigidity ϰc for these bilayers at different levels of hydration. The obtained values of ϰc turn out to be too large compared with the literature. However, using recent LU models (B. Halle) which include the obvious couplings between neighbouring bilayers at low Larmor frequencies, the corrected ϰc of the fully hydrated membrane systems are comparable to those obtained from the standard videooptical experiments. Therefore proton spin relaxation measure-ments at low Larmor frequencies with the field-cycling technique are a suitable means to determine the bending rigidity ϰc of model membrane systems at low hydrations and of systems containing surfactants.
Helium Atom Scattering from C2H6, F2HCCH3, F3CCH2F and C2F6 in Crossed Molecular Beams
Authors: Hammer Markus , Seidel Wolfhart
Published: February 2015

Rotationally unresolved differential cross sections were measured in crossed molecular beam experiments by scattering Helium atoms from Ethane, 1,1-Difluoroethane, 1,1,1,2-Tetrafluoroethane and Hexafluoroethane. The damping of observed diffraction oscillations was used to extract anisotropic interaction potentials for these scattering systems applying the infinite order sudden approximation (IOSA). Binary macroscopic parameters such as second heterogeneous virial coefficients and the coefficients of diffusion and viscosity were computed from these potentials and compared to results from macroscopic experiments.
Radiative Lifetimes of The Perturbed 6snf3 F3 , 1F3 , and 3F4 Rydberg Sequences of Barium
Authors: Zaki Ewiss M. A.
Published: February 2015

Extensive new results for the natural radiative lifetimes of the perturbed odd-parity 6snf 3F3, 1F3, and 3F4 sequences of barium (with 11 < n < 40, 11 < n < 40 and 13 < n < 40, respectively) have been calculated. The calculations were performed in the framework of multichannel quantum defect theory. The contributions to the transition probabilities of all known even-parity levels of the 6snd and 6sng configurations together with their perturber states and connected via the electric dipole operator with the 6snf 3F, 1F3, and 3F4 levels, are considered.

The results for the 6snf 1F3 and 3F4 sequences, in contrast with those for the 6snf 3F3 series, show strong deviation from a hydrogenic scaling law. This deviation reflects the extended perturbations of these levels by some of the doubly excited states of the same parity.
The Square Root Approximation to the Dispersion Relation of the Axially-symmetric Electron Wave on a Cylindrical Plasma
Authors: Babović V.M. , Aničin B.A. , Davidović D. M.
Published: February 2015

This paper suggests the use of a simple square root approximation to the dispersion relation of axially-symmetric electron surface waves on cylindrical plasmas. The point is not merely to substitute the exact expression for the dispersion relation which involves a number of Bessel functions with a more tractable analytical approximant, but to cast the dispersion relation in a form useful in the comparison with other waves, such as water surface gravity waves and the associated tide-rip effect. The square root form of the dispersion relation is also of help in the analysis of surfactron plasmas, as it directly predicts a linear roll-off of electron density in the discharge.
Dilatometric Studies Across the Isotropic to Smectic-F Transition
Authors: Srinivasulu M. , Potukuchi D. M. , Pisipati V. G. K. M.
Published: February 2015

Thermal Microscopy (TM), Differential Scanning Calorimetry (DSC) and dilatometric studies were carried out to characterise the liquid crystalline phases and mesomorphic transitions exhibited by three higher homologues of N-(p-n-dodecyloxy benzylidene)p-n-alkyl anilines, viz., N-(p-n-dodecyloxy benzylidene)p-n-dodecyl aniline, (12O.12), N-(p-n-dodecyloxy benzylidene)p-n-tetradecyl aniline, (12O.14) and (N-(p-n-dodecyloxy benzylidene)p-n-hexadecyl aniline, (12O.16). The three com-pounds exhibit enantiotropic smectic-F and smectic-G liquid crystalline phases between the isotropic liquid and the solid crystal. The change in density across the phase transformations and the thermal expansion coefficient confirm the first order nature of the isotropic to smectic-F (I-SmF) and smectic-F to smectic-G (SmF-SmG) transitions. The dilatometric studies infer strong pre-transitional fluctuations in a relatively large thermal range. The pre-transitional effects are estimated by αeff in the vicinity of the mesomorphic fluctuation-dominated non-linear region (FDNLR) of the I-SmF transition. The strength of non linear growth of density fluctuations is discussed in the wake of reports at the I-N, I-SmA and I-SmC transitions.
Quantum Constraints in π Systems: The Role of the Pauli Antisymmetry Principle for π Electronic Properties
Authors: Böhm Michael C. , Schütt Johannes
Published: February 2015

It is demonstrated that the Pauli antisymmetry principle (PAP) is without influence in the π electron subspace of polyenes and (4n + 2) annulenes (n = 0, 1, 2...) as long as the hoppings are restricted to nearest-neighbour centers. Here the π electrons behave like a hard core bosonic (hcb) ensemble where fermionic on-site and bosonic intersite properties are combined. In 4n and (2n + 1) annulenes (n = 1,2, 3...) π electron jumps between the first and last ring atom lead to a Pauli antisymmetry-based destabilization. The second quantum constraint in fermionic systems is the Pauli exclusion principle (PEP). In the many-electron basis adopted in the present work it is possible to treat the PAP and PEP as two decoupled constraints. The electronic destabilization due to the PEP is enhanced with increasing size of the system. The influence of the PAP and PEP on the π electrons is discussed in terms of π energies and charge fluctuations. The model Hamiltonians adopted are of the Hückel molecular orbital (HMO) and Pariser-Parr-Pople (PPP) type. We suggest quantum statistical definitions of the quantities "aromaticity" and "antiaromaticity", qualitative descriptors which are widely employed in the chemical literature.
On the Role of the Pauli Antisymmetry Principle in Pericyclic Reactions
Authors: Böhm Michael C. , Schütt Johannes
Published: February 2015

In the present work we discuss the role of the Pauli antisymmetry principle (PAP) in synchronous pericyclic reactions. These reactions are allowed in the electronic ground state whenever the PAP does not act as a quantum constraint in the transition state. The possible suppression of the influence of the PAP is a peculiarity of π electron systems. The PAP is a hidden (= deactivated) variable in the π electron subspace of polyenes and (4n + 2) annulenes (n = 0, 1, 2,...). In 4n annulenes (n = 1, 2, 3,...) it leads to minority signs in the kinetic hopping matrix of the π electronic wave function and thus to an energetic destabilization. The quantum statistical difference between the above families of π systems renders possible a microscopical definition of the quantities “aromaticity” and “antiaromaticity”. The sign behaviour of the kinetic hopping elements is used in the discussion of pericyclic reactions. The present quantum statistical description of these reactions is related to the Dewar-Zimmermann and Woodward-Hoffmann rules.
EPR Study of VO2+ and Cr3+ in Li2SO4 · H2O Single Crystal
Authors: Çelik F. , Köksal F. , Kartal İ. , Gümüş H.
Published: February 2015

A single crystal X-band EPR study of VO2+ and Cr3+ in Li2SO4 • H2O was carried out at room temperature. Analysis of the spectra indicates that VO2+ substitutes for Li+ and that there are two magnetically inequivalent Li+ sites. The charge compensation occurs by removal of a neighboring Li+ . The principal values of the g and A tensors of the spin Hamiltonian for the two sites were determined. Superhyperfine interaction of the 3d1 electron of VO2+ with the neighboring water protons in the unit cell was observed and found to be between 0 and 0.5 mT, depending on the orientation of the magnetic field. Two magnetically different sites were also observed for Cr3+ , and the results were explained by a rhombic spin Hamiltonian. The Hamiltonian parameters g, D, and E were determined. It is concluded that VO2+ and Cr3+ enter into the Li+ places and the charge is compensated by a Li+ vacancy in the VO2+ case and proton vacancies in the Cr3+ case.
Zonar Distribution of 18O in Synthetic Quartz Crystals
Authors: Klemm A. , Röller K. , Hoernes S.
Published: February 2015

The 18O-content in the mantle-zones of a commercial synthetic quartz was found to increase from the seed towards the surface by 7 ‰. Since the growth took place in a closed container, calculations for the evolution towards the steady state of the 18O-transport could be performed. In the steady state the concentrations of 18O and impurities in the growing quartz are uniform.
The Microwave Spectrum of the Bimolecule Trifluoroacetic Acid · · · Cyclopropanecarboxylic Acid
Authors: Antolínez Sonja , Dreizler Helmut , Storm Volker , Sutter Dieter H. , Alonso José L.
Published: February 2015

We have investigated the microwave spectrum of the bimolecule trifluoroacetic acid • • • cyclo-propanecarboxylic acid in the region 1 to 4 GHz, where the low J transitions of this heavy complex appear. The measured μa -R branch transition frequencies were fitted to determine the rotational constants and three centrifugal distortion constants. With the assumption that the structures of the subunits remain unchanged upon complexation, the O • • • O distances of the hydrogen bridge bonds are determined as 2.62 A.
NMR Studies on the Dynamics of Intercalated Water in Li-saponite
Authors: Ishimaru Shin'ichi , Ikeda Ryuichi
Published: February 2015

The dynamics of intercalated water molecules in Li-saponite was studied by measurement of solid state 2H and 7Li NMR spectra and of the 2H spin-lattice relaxation time at 175 ~ 350 K. Only a single component was observed in the 2H spectra above 260 K, suggesting that the water hydrogens rapidly exchange their positions between various distinct environments. Analysis of the observed spectra suggests that the water molecules possess C2 rotational freedom at around 260 K and that the hydration shell around Li+ cations is highly symmetrical in the same temperature region
Copper Contamination Mechanism of Silicon Substrates from HF Solutions
Authors: Bertagna Valérie , Rouelle François , Chemla Marius
Published: February 2015

The contamination of silicon wafers from dilute HF solutions containing ultratrace levels of metallic ion impurities is a subject of constant interest. The mechanism of copper electroless deposition from HF onto monocrystalline silicon was investigated using a new electrochemical cell, which proved to be a very sensitive detector for in situ characterization of silicon surfaces.

Upon addition of copper trace amounts, the open-circuit potential was observed to shift rapidly towards more positive values at a rate nearly proportional to the copper concentration. All potential/ time curves tend to reach a limiting value of the potential, while quantitative measurements of radioactive tracers revealed that during a few tens of minutes, copper ions were continuously reduced on the silicon surface.

Electrochemical potentials and voltammetric measurements were interpreted in terms of the mixed potential theory and led to the conclusion that copper nuclei act as a catalyst which enhances the cathodic activity for protons reduction. The model was supported by AFM observations which demonstrated the initiation of corrosion pits around the nuclei.
Differential Thermal Analysis and PVT Measurements on 2,2,2-Trichloro-ethanol Under High Pressure
Authors: Jenau M. , Sandmann M. , Würflinger A. , Tamarit J. Ll.
Published: February 2015

The phase behaviour, the calorimetric and volumetric properties of 2,2,2-trichloro-ethanol (TCE) have been studied with differential thermal analysis (DTA) and pVT measurements in the pressure range 1 atm to 300 MPa and temperatures between 250 K to 355 K. TCE displays a metastable plastic phase (solid I') and a non-plastic solid phase II at atmospheric pressure. At least two pressure-induced solid phases have been detected: a stable plastic phase (solid I') and a non-plastic phase (solid III). There are two sets of triple points: a) 123 MPa and 308 K with the phases solid I, solid II and the liquid, b) 243 MPa and 316 K for solid I, II, III. Furthermore a metastable low-temperature brittle form (solid II') has been found, which transforms to solid I at a considerably lower temperature than solid II. The melting curve of solid I' can be pursued to higher pressures up to 260 MPa. On the other hand, the melting curve of the stable plastic phase solid I can be extrapolated beyond the triple point to pressures below 123 MPa. Volume and enthalpy changes are reported for all phase transitions.
Ionic Motion of Phenethylammonium Ion in [C6H5CH2CH2NH3]2 PbX4 (X = Cl, Br, I) as Studied by 1 H NMR
Authors: Ueda Takahiro , Omo Mariko , Shimizu Katsuyuki , Ohki Hiroshi , Okuda Tsutomu
Published: February 2015

The temperature dependences at 110 to 400 K of the : 1H spin-lattice relaxation time (7\) of the phenethylammonium ion in phenethylammonium lead(II) halides, [C6H5CH2CH2NH3]2PbX4 (X = Cl, Br, I), revealed that this ion shows reorientation of the NH3 moiety around the three-fold axis and torsional motion of the alkyl chain (CH2CH2). Below room temperature, the chloride and the bromide yielded two minima of 1H T1 originating from NH3 reorientation, whereas the iodide yielded only one minimum. These findings indicate that there are two kinds of NH3 sites in the chloride and bromide but only one in the iodide. The T1 minimum observed below room temperature gave similar activation energies of the NH3 reorientation, Ea = 15.7,15.1 and 15.5 kJ mol 1 for the chloride, bromide and iodide, respectively, suggesting that the corresponding NH3 groups are located at similar environments. Above room temperature, the T1 minimum in the chloride and bromide gave larger Ea values of the NH3 reorientation: Ea - 23.6 and 20.2 kJ mol-1 for the chloride and bromide, respectively. These findings suggest that the NH3 groups form stronger hydrogen bonding with halogen atoms (N-H ... X). Furthermore, the amplitude of the CH2CH2 motion is discussed, using the two sites jump model. The activation energies for the CH2CH2 motion in these compounds are almost equal (Ea = 29.1, 30.0 and 28.2 kJ mol -1 for the chloride, bromide and iodide, respectively), but that the torsional angles become larger in the order iodide ⪡ bromide<chloride.
Chaotic Spike Patterns Evoked by Periodic Inhibition of Rat Cortical Neurons
Authors: Schindler K. A. , Bernasconi C. A. , Stoop R. , Goodman P. H. , Douglas R. J.
Published: February 2015

We use methods of nonlinear dynamics to describe the effect of periodic inhibition on the patterns of action potentials generated by regular spiking rat cortical neuron in vitro. Both direct measurements and our mathematical model reveal that chaotic patterns of discharge can be evoked at certain frequencies of inhibitory stimulation. We use detailed biophysical simulation of a cortical neuron to explain the firing patterns in terms of known membrane ionic conductances.
The Complete Bifurcation Diagram for the Logistic Map
Authors: Tsuchiya Takashi , Yamagishi Daisuke
Published: February 2015

The complete bifurcation diagram as well as the basin of attraction for the logistic map is presented for the whole range of the control parameters, namely -2≤a≤4 where the system remains finite. Equivalence of the newly found bifurcation branch to the conventional branch is shown.
X-ray Diffraction Studies on Supercooled Aqueous Lithium Bromide and Lithium Iodide Solutions
Authors: Takamuku Toshiyuki , Yamagami Motoyuki , Wakita Hisanobu , Yamaguchi Toshio
Published: February 2015

X-ray diffraction measurements were performed on liquid LiBr • 5H2O and Lil • 5H2O at temperatures from -30 to 25 °C. The total radial distribution functions did show that on supercooling the hydration shell of the halide ions becomes more structured, while that of the lithium ions becomes distorted. The larger the halide ion, the stronger becomes the water-water interaction around halide ions with lowering temperature. However, the distance between the water molecules in the hydration shells of the halide ions depends little on their size. On the basis of the present results, together with those of our previous investigation on LiCl • 5H2O at temperatures from - 135 to 100°C, the effects of temperature and the size of the halide ions on the structure of the solution are discussed.
Hydromagnetic Stability of Two Rivlin-Ericksen Elastico-Viscous Superposed Conducting Fluids
Authors: Sharma R. C. , Kumar P.
Published: February 2015

The stability of the plane interface separating two Rivlin-Ericksen elastico-viscous superposed fluids of uniform densities when the whole system is immersed in a uniform horizontal magnetic field has been studied. The stability analysis has been carried out, for mathematical simplicity, for two highly viscous fluids of equal kinematic viscosities and equal kinematic viscoelasticities. It is found that the stability criterion is independent of the effects of viscosity and viscoelasticity and is dependent on the orientation and magnitude of the magnetic field. The magnetic field is found to stabilize a certain wave-number range of the unstable configuration. The behaviour of growth rates with respect to kinematic viscosity and kinematic viscoelasticity parameters are examined numerically.
Linear and Non-linear Polarizabilities for P2(X1Σg
+)
Authors: Maroulis George
Published: February 2015

Electric polarizabilities and hyperpolarizabilities were calculated from accurate self-consistent field wavefunctions for P2. The following values are reported, using the experimental bond length of 1.8934 Å: dipole polarizability αzz = 69.83 and αxx = 41.20 e2 a0
2 Eh-1 , second dipole hyperpolarizability γzzzz = 17 040, γxxxx= 11 581 and γxxzz = 4724 e4a0
4Eh
-3, quadrupole polarizability, Czz „zz = 276.14, Cxz,xz = 232.64 and Cxx,xx = 151.25 e2 a0
4Eh
-1 , dipole-octopole polarizability, Ez,zzz, = 331.00 and Ex,xxx = -154.66 e2 a0
4Eh
-1 and for the dipole-dipole-quadrupole hyperpolarizability, Bzz,zz = - 2441, Bxz,xz = - 1442, Bxx,zz = 866 and Bxx,xx = - 1411 e3a0
4Eh-2.
Parametric Excitation of Breathers in a Nonlinear Lattice
Authors: Abel Markus , Pikovsky Arkady
Published: February 2015

We investigate localized periodic solutions (breathers) in a lattice of parametrically driven, nonlinear dissipative oscillators. These breathers are demonstrated to be exponentially localized, with two characteristic localization lengths. The crossover between the two lengths is shown to be related to the transition in the phase of the lattice oscillations.
On the Correspondence of Time-Delay and Spatially Extended Systems
Authors: Bünner M. J. , Meyer Th. , Kittel A. , Par J.
Published: February 2015

We establish a straightforward connection between spatially extended systems, the dynamics of which are modeled with the help of partial differential equations and time-delay systems. To this end, we give a linear partial differential equation with a nonlinear boundary condition whose solutions are equivalent to the solutions of a time-delay differential equation. We observe that the phase space of these systems exhibits a pronounced structure. In this paper, we express the structure of the phase space of time-delay systems and the corresponding spatially extended system by distinguishing between a ‘linear subsystem’ and a ‘localized nonlinearity’. We find that the high-dimensional chaotic dynamics observed in time-delay systems is fundamentally different from the spatio-temporal chaos observed in homogeneous spatially extended systems, the dynamics of which is modeled with the help of nonlinear partial differential equations. To this end, we investigate the space-time correlation function and the ‘thermodynamic limit’.
Space-Discretized Verlet-Algorithm from a Variational Principle
Authors: Nadler Walter , Diebner Hans H. , Rössler Otto E.
Published: February 2015

A form of the Verlet-algorithm for the integration of Newton’s equations of motion is derived from Hamilton's principle in discretized space and time. It allows the computation of exactly time-reversible trajectories on a digital computer, offers the possibility of systematically investigating the effects of space discretization, and provides a criterion as to when a trajectory ceases to be physical.
Scaling Properties of Traffic-flow Data
Authors: Wagner Peter , Peinke Joachim
Published: February 2015

By computing the probability distributions of the velocity difference between cars a time-delay τ apart, the scaling properties of traffic flow can be analysed. These data display scaling behaviour thus confirming earlier results that have found 1/ fα -noise in traffic flow. Furthermore, the applicability of the scaling analysis for describing the two-point statistics of traffic flow is demonstrated, leading to an additional test for the dynamical properties of microscopic and macroscopic traffic flow models.
Construction of Chaotically Synchronizing Systems and Some Methods of Controlling Chaos
Authors: Posiewnik Andrzej
Published: February 2015

We propose a method of contructing chaotically synchronizing systems and give examples of two control algorithms based on properties of Lipschitz maps. Bifurcation diagrams show the robustness of the method for broad band of control parameters.
Combined High Resolution UV and Microwave Results: Structure of the Benzonitrile•Water Complex
Authors: Helm R. M. , Vogel H.-P. , Neusser H. J. , Storm V. , Consalvo D. , Dreizler H.
Published: February 2015

High resolution ultraviolet (UV) and molecular beam Fourier transform microwave (MB FTMW) spectroscopy of the benzonitrile·water (BZNW) cluster were performed to measure cluster structures in the S0 and S1 states. The MW experiments provide additional information on the structure and the 14N-nuclear quadrupole coupling in the ground state So, the UV experiments on the dynamics in Si. The rotationally resolved sub-Doppler UV spectra of BZNW were measured by mass-selective resonance-enhanced two-photon ionization. For the first time this UV technique has been applied to hydrogen-bonded clusters. From the UV spectra the rotational constants are obtained by Correlation Automated Rotational Fitting. The MW spectra were analyzed with the model of a centrifugally distorted rotor including nuclear quadrupole coupling. A r0 -fit of the water position within the cluster is performed. The water is found to be located with its oxygen nearly in the plane of benzonitrile (BZN). For S0 (S1), the distance of the oxygen to the ortho hydrogen is r0 = 2.477(4) Å (2.457(2) Å) and the angle to the ortho carbon-hydrogen bond 143.34(2)° (141.91(3)°). The structure differences in S1 and S0 can be explained by the structure changes of the BZN molecule. A line broadening, which points to a faster decay in Si upon clustering with the polar solvent, is observed for the BZNW cluster.
The Inversion Invariance of the Lorentz Transformation
Authors: Sallhofer Hans
Published: February 2015

It is shown that the fundamental quantity v of the inverse transformation does not turn out to be negative.
Crystal Structure of the High-temperature Solid Phases of Choline Tetrafluoroborate and Iodide
Authors: Ishida Hiroyuki , Ono Hiroshi , Ikeda Ryuichi
Published: February 2015

The crystal structure of the highest-and second highest-temperature solid phases of choline tetrafluoroborate and iodide was determined by X-ray powder diffraction. The structure in the highest-temperature phase of both salts is NaCl-type cubic (a = 10.16(2) Å, Z = 4 for tetrafluorobo-rate; a = 10.08(2) Å, Z = 4 for iodide). The second highest-temperature phase of tetrafluoroborate and iodide is CsCl-type cubic (a = 6.198(6) Å and Z = 1) and tetragonal (a = 8.706(2) Å, c = 6.144(6) Å, and Z = 2), respectively. DSC was carried out for the iodide, where the presence of three solid-solid phase transitions was confirmed. Enthalpy and entropy changes of these transitions were evaluated.
High Resolution FTIR Spectroscopy of 1,3,5-Triazine*: The Parallel Bands v11 and v12 of 12C3
14N3H3, 13C3
14N3H3 , 12C3
15N3H3 , 13C3
15N3H3 and 12C3
14N3D3
Authors: Bodenmüller W. , Pfeffer M. , Ruber R. , Macht B. , Ruoff A.
Published: February 2015

The present contribution reports on the analysis of the high resolution FTIR spectra of the only two IR-active parallel fundamentals ν11 and ν12 of the isotopomers 12C3
14N3H3 , 13C3
14N3H3 , 12C3
15N3H3 , C3
15N3H3 and 12C3
14N3D3 , respectively, of 1,3,5-triazine. The molecular constants of the ground state and the upper states ν11 = 1 and ν12 = 1, respectively, for all molecules under consideration are listed. The enhancement of the P-and the depletion of the R-banches, observed in the v11 bands of all non-deuterated isotopomers, is discussed, and the Herman-Wallis constants obtained are given.
Mössbauer Studies of Fe2+ in Iron Langbeinites and other Crystals with Langbeinite Structure
Authors: Windhaus M. , Mosel B. D. , Müller-Warmuth W.
Published: February 2015

57 Fe Mössbauer spectra have been measured at various temperatures between 4.2 K and 300 K for iron langbeinites A 2 Fe 2^04)3 with A = K, NH 4 , Rb, T1 and magnesium, manganese and cadmium lang-beinites doped with Fe" + . The spectra revealed several contributions whose isomer shifts and quadru-pole splittings have been obtained by fitting program routines. For the high-temperature cubic phases two crystallographically non-equivalent iron sites have been identified, characteristic of Fe2+ in the high-spin state. Abrupt changes of the quadrupole couplings indicated phase transitions; in some cases, the spectra have also revealed several sites for Fe2+ in low temperature phases. From the temperature dependences, phase transition temperatures, crystal field splittings and Debye temperatures have been derived.
Internal Cation Mobilities in Molten (K, Dy1/3)Cl
Authors: Matsuura Haruaki , Okada Isao , Takagi Ryuzo , Iwadate Yasuhiko
Published: February 2015

Internal cation mobility ratios in the molten system KCl-DyCl3 have been measured at 1093 K by Klemm's countercurrent electromigration method. From these, and data available on the conductivities and molar volumes of the mixtures, the internal mobilities b of both cations have been calculated. With increasing concentration of Dy, bK decreases. The decrease of bK is attributed to the tranquilization effect by Dy3+ ions which strongly interact with Cl- ions. With increasing concentration of K+ , bDy decreases; this may be attributed to the stronger association of Dy3+ with C- ions due to the enhanced charge asymmetry of the two cations neighboring to the C- ions. It could not been clarified whether a species such as [DyCl6]3- is also an electrically-conducting species in the K+ rich range.
The Molecular Zeeman Effect of Norbornadiene, its g-Values, Magnetizability Anisotropics, and Molecular Electric Quadrupole Moment; A High-Resolution Microwave Fourier-Transform Study Combined with Quantum Chemical Calculations
Authors: Voges K. , Sutter D. H. , Ruud K. , Helgaker T.
Published: February 2015

The molecular Zeeman effect is reported for norbornadiene at fields near 18 kG. The experimental results are for the molecular g-values: gaa = 0.02860(16), gbb = 0.05271(11), gcc = 0.00142(26), for the magnetizability anisotropics: 2ξaa - ξbb - ξcc = -0.41(26) · 10-6 ergG-2 mol-1 , 2ξbb - ξcc - ξaa = +40.72(27) · 10-6 erg G-2 mol-1 and for the molecular electric quadrupole moments: Qaa = -1.78(20) · 10 -26 esu cm2 , Qbb = 3.73(20) · 10-26 esu cm2 , Qcc = -1.94(30) · 10-26 esu cm2 , with the c-axis of the molecular inertia tensor aligned to the C2v-axis of the equilibrium configuration. The results of ab-initio calculations, using London type atomic orbitals as basis functions, are reported for the g-tensor, the magnetizability tensor and the molecular electric quadrupole moment tensor and are compared to the experimental findings. The possibilities of strain induced magnetizability exaltations and of systematic differences between gas phase and bulk phase magnetizabilities are discussed.
An X-ray Diffraction Study of the Structure of Vitreous P2O5
Authors: Hoppe Uwe , Walter Günter , Kranold Rainer , Stachel Dörte
Published: February 2015

Recently, the lengths of the two P-O bonds in the PO4 tetrahedron were obtained by neutron diffraction of high real-space resolution. By use of the present X-ray diffraction experiments, the P-P distance belonging to pairs of corner-linked PO4 units is determined. Using this length of (294 ± 2) pm and taking into account the P-0 bond distance to the bridging oxygen atom of 158 pm, a mean P-O-P angle of 137° ± 3° is calculated. The reverse Monte Carlo simulations fit the neutron and X-ray structure factors. The P-O-P angle distribution obtained this way possesses a mean angle of 141°. An interpretation of the first scattering peaks is presented by analysing the occupancy and the distances of various co-ordination shells by use of model configurations. The low occupancy of the first shells allows the application of the schematic hole model of Dixmier. The first X-ray diffraction peak at 13 nm-1 is related to the P-P2nd shell, the shoulder at 20 nm-1 arises from the P-O2nd shell. The most similar crystalline structure with vitreous P2O5 is the orthorhombic P2O5, form II. But it has more effectively orientated terminal oxygen atoms and, thus, a higher packing than the glass.
Spatio-temporal Analysis of Electroconvection in Nematics
Authors: Amm Heidrun , Grigutsch Maren , Stannarius Ralf
Published: February 2015

We investigate electroconvection in nematic liquid crystals by means of optical microscopy. Time resolved optical images are used to study the director dynamics. For the first time we present instant images in the dielectric regime. A numerical simulation of the optical transmission patterns is performed on the basis of Fermat's principle. In the instant images of dielectric rolls, the periodicity of the observed optical pattern is equal to the wavelength λ0 of the convection rolls. The well known low contrast 'stationary' optical texture observed in conventional experiments results from time averaging of these instant images; its wavelength is λ0/2.
Study of the Atomic Structure and Phase Separation in Amorphous Si-C-N Ceramics by X-Ray and Neutron Diffraction
Authors: Schempp S. , Dürr J. , Lamparter P. , Bill J. , Aldinger F.
Published: February 2015

Amorphous Si37C32N31 and Si37C29N34 ceramics were produced by pyrolysis of a polyhy-dromethylsilazane precursor. Their structure was investigated by X-ray and neutron diffraction. Wide angle diffraction showed that the Si-atoms are preferentially bonded to nitrogen atoms, but also bonding to carbon atoms was found. This suggests that the excess carbon atoms form an amorphous graphite-like phase. Small angle scattering revealed that the ceramics are inhomogeneous. The evolution of the phase separation during annealing was investigated and it was concluded that amorphous Si3N4 precipitates grow in the Si-C-N materials. The results are compared with previous results for amorphous Si24C43N33 produced from a polysilylcarbodiimide precursor [1 - 3].
Structural and Magnetic Characterization of Mixed Oxides: A Study of Li-Ni-O and Li-Mn-O Systems
Authors: Massarotti V. , Capsoni D. , Bini M. , Azzonia C. B. , Mozzati M. C. , Paleari A.
Published: February 2015

The present paper details the way to determine the cation distribution in mixed oxides with transition ions from the diffraction and magnetic susceptibility data. This approach allows one to determine phase abundances and phase compositions by two combined procedures. By X-ray diffraction Rietveld profile refinement and magnetic susceptibility data analysis it is possible to estimate the ratio and the occupancy factor of paramagnetic ions in different oxidation states. A brief discussion of practical cases is reported. In the Li-Ni-O system the lithium cationic fraction of the ordered phase Li2xNi2-2XO2 increases monotonically with the total lithium fraction xt
for 0.31 < xt
< 0.46. In the Li-Mn-O system for 0.36 ≤ xt ≤ 0.53 the Li2MnO3 fraction has been determined, and for the coexistent Li [LiyMn2-y]O4 spinel phase the dependence of y on xt
has been evaluated.
The Glass Transition Within the Thermodynamics of Irreversible Processes
Authors: Baur H.
Published: February 2015

The glass transition caused by a finite cooling rate is a continuous non-linear dissipative process whose description requires a clear distinction between equilibrium and non-equilibrium quantities. The so-called Davies or Prigogine-Defay relations (in form of an equation as well as in form of an inequality) are not relevant in such a process. The determining quantities of the glass transition are -from a macroscopic phenomenological point of view -the fluidity of the melt and the partial free enthalpy of the microscopic vacancies in the melt. All of the characteristics of the dynamics of the glass transition are essentially due to these two quantities.
Zero Eigenvalue Analysis for the Determination of Multiple Steady States in Reaction Networks
Authors: Li Hsing-Ya
Published: February 2015

A chemical reaction network can admit multiple positive steady states if and only if there exists a positive steady state having a zero eigenvalue with its eigenvector in the stoichiometric subspace. A zero eigenvalue analysis is proposed which provides a necessary and sufficient condition to determine the possibility of the existence of such a steady state. The condition forms a system of inequalities and equations. If a set of solutions for the system is found, then the network under study is able to admit multiple positive steady states for some positive rate constants. Otherwise, the network can exhibit at most one steady state, no matter what positive rate constants the system might have. The construction of a zero-eigenvalue positive steady state and a set of positive rate constants is also presented. The analysis is demonstrated by two examples.
Notiz: The Trouton-Hildebrand-Everett Rule
Authors: Logan S. R.
Published: February 2015

Fundamental scientific reasons are advanced for preferring the formulation of the THE Rule offered in a Note of 1996 to that employed by Rooney in a Note of 1997. These illustrate that, whereas Transition State theory has been of considerable service to the development of chemical kinetics, it has not been of any utility in regard to issues of thermodynamics
Manifestation of Quantum Interference in Lasing Without Inversion
Authors: Lee Hwang , Scully Marian O.
Published: February 2015

In terms of quantum interference we demonstrate the physical mechanisms which lead to light amplification without population inversion. The similarities and differences between the two model schemes, namely, A and V-type, are emphasized. A coherent radiation field, on one hand, which drives one of the lasing levels, yields the quantum mechanical two paths via Autler-Townes splittings. On the other hand, the spontaneous emission in this driving transition plays a key role in the asymmetries between the absorption and the stimulated emission in the lasing transition.
Long-time Dynamics of Spontaneous Parametric Down-conversion and Quantum Limitations of Conversion Efficiency
Authors: Fleischhauer Michael , Veits Oliver
Published: February 2015

We analyze the long-time quantum dynamics of degenerate parametric down-conversion from an initial sub-harmonic vacuum (spontaenous down-conversion). Standard linearization of the Heisenberg equations of motion fails in this case, since it is based on an expansion around an unstable classical solution and neglects pump depletion. Introducing a mean-field approximation we find a periodic exchange of energy between the pump and subharmonic mode goverened by an anharmonic pendulum equation. From this equation the optimum interaction time or crystal length for maximum conversion can be determined. A numerical integration of the 2-mode Schrödinger equation using a dynamically optimized basis of displaced and squeezed number states verifies the characteristic times predicted by the mean-field approximation. In contrast to semiclassical and mean-field predictions it is found that quantum fluctuations of the pump mode lead to a substantial limitation of the efficiency of parametric down-conversion.
Symmetrie and Asymmetrie Nuclear Matter in the Thomas-Fermi Model at Finite Temperatures
Authors: Strobel K. , Weber F. , Weigel M. K.
Published: February 2015

The properties of warm symmetric and asymmetric nuclear matter are investigated in the frame of the Thomas-Fermi approximation using a recent modern parameterization of the effective nucleon-nucleon interaction of Myers and Świątecki. Special attention is paid to the liquid-gas phase transition, which is of special interest in modern nuclear physics. We have determined the critical temperature, critical density and the so-called flash temperature. Furthermore, the equation of state for cold neutron star matter is calculated.