bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin-Lattice Relaxation Times of 1H in Aqueous Gadolinium Chloride Solutions
Authors: Köhnlein Doris , Lutz Otto , Ulmer Reiner
Published: February 2015

Spin-lattice relaxation times T1 of protons in aqueous solutions of gadolinium chloride have been measured at 2.11 T for a larger range of concentrations down to 0.035 millimolal. Very small amounts of GdCl3 decrease strongly T1 of the water protons.
Simulation of Amplitude Behaviour in the Ag+ Perturbed Excitable Belousov-Zhabotinsky Reaction by the Oregonator Model
Authors: Ruoff Peter
Published: February 2015

Potentiometrie measurements with platinum and silver electrodes of Ag+ induced oscillations in the oxygen-inhibited excitable Belousov-Zhabotinsky system are reported. Calculations based on the Oregonator model lead to the conclusion that the platinum electrode's potential is composed of two contributions, the Ce(III)/Ce(IV) redox couple which dominates at low Ag+ flow rates and the contribution of HBrO2 , HOBr and BrO2 which dominates at higher Ag+ addition rates.
Molecular Vibration Analysis of the Cage-Like Molecules β-P4S5, As4S5, P4S7, and AS2P2S7
Authors: Cyvin S. J. , Cyvin B. N. , Motz H. , Wibbelmann C.
Published: February 2015

The cage-like molecules β-P4S5 , As4 S5 , P4S7 and As2P2S7 are all supposed to have C2v -symmetry. A normal coordinate analysis was performed for those molecules, based on a very simple initial force field with three numerical parameters and valence coordinates including redundancies. A complete set of symmetry coordinates is given. The force field was refined by adjusting the symmetry force constants to fit exactly a set of observed frequencies. This was used to calculate the mean amplitudes of vibration and perpendicular amplitude correction coefficients. The standard thermodynamical values derived from spectroscopic data are also given. A set of frequencies was calculated for the so far unknown compound P4S6 .
Exact Solutions of Simple Nonlinear Difference Equation Systems that show Chaotic Behavior
Authors: Tsuchiya Taskashi , Szabo Attila , Saitô Nobuhiko
Published: February 2015

Exact solutions are given for May's simple difference equation and the broken linear model, both for extreme values of the parameters, and the relation between these two systems for the solvable cases is clarified. The invariant measure and the correlation function for each case are calculated using the exact solutions. The initial-value dependence of the behavior of the solutions, choatic or periodic, is completely determined. By using the exact solution, encounters of any two nonperiodic orbits can be precisely analyzed.
The Raman Spectra and Conformational Change of Simple Sodium Alkylsulfates and Sodium Alkyisulfonates in Aqueous Solution
Authors: Ikeda Teruki , Yoshida Tadayoshi , Okabayashi Hirofumi
Published: February 2015

In order to study the polar group effect upon conformations about CH2-CH2 single bonds, the Raman spectra of simple sodium alkylsulfates and sodium alkyisulfonates were measured. The ethylsulfate ion (CH3-CH2-O-SO3
-) in aqueous solution was found to take the trans form about the CH2 - O bond in 0.67-5.41 mol/1. For the n-propylsulfonate ion the Raman line due to the gauche form about the CH2 -CH2 bond was also observed, the trans form becoming predominant at higher concentrations. For the sulfate and sulfonate ions having butyl and hexyl chains, the concentration dependence of their molecular conformations was also investigated.
On the Role of Microcrystal Formation in Intermolecular Triplet-Triplet Energy Transfer in Rigid Glasses
Authors: Zander M.
Published: February 2015

The intermolecular triplet-triplet energy transfer system benzophenone (donor)/naphthalene (acceptor) was studied in various rigid glasses at 77 K. It is shown that energy transfer is much more efficient if the donor is present in the form of microcrystals than in the case where both donor and acceptor compound are in true solution.
A Carbon-13 Spin-Lattice Relaxation Studies of Simple Alkylsulfates and Alkylsulfonates in Aqueous Solution
Authors: Matsushita Kazuhiro , Terada Yukimasa , Yoshida Tadayoshi , Okabayashi Hirofumi
Published: February 2015

The C-13 spin-lattice relaxation times (T1) of a series of short-chain n-alkylsulfates and sulfonates in D2O solutions were measured at various concentrations. Even for ethylsulfate and n-propylsulfonate ions, inflections, due to association, in the reciprocal of the T1 vs. the inverse concentration plots were observed. The critical micelle concentrations (CMC's) of ethyl and butylsulfates are 3.0 and 2.5 mol/l, respectively, and those of propyl and butylsulfonate 2.3 and 1.9 mol/l, respectively. For the simple alkylsulfates, below the CMC a progressive decrease in T1 from the terminal methyl group towards the polar group was observed.
On the Reaction Mechanism of Scavenged Hydrocarbon Radiolysis
Authors: Földiák G. , Schüler R. H.
Published: February 2015

It is shown that in radiolysis not only the reaction of alkyl radicals with iodine, but also that of alkyl radicals with galvinoxyl is diffusion controlled. The activation energies of the reactions of alkyl radicals with iodine increase with molecular mass, following the Smoluchowski equation. In the gross reaction other reaction steps (e.g. polymerisation, combination) cover up this phenomenon.
Contribution of the Torsional Modes to the Equilibrium Distribution of Vibrational States and to the Specific Heat of a Chain Molecule
Authors: Costa J. A. Borges da , Scherer C. , Holz A. , Naghizadeh J.
Published: February 2015

The torsional modes of a chain molecule were studied recently under the assumption that it has a well defined spatial configuration at any time. Here we show how the averages over the possible configurations, for a distribution in thermal equilibrium, should be performed in the calculation of the thermodynamical properties. Our results show that the mean density of torsional states increases in the low frequency region with increasing temperature. The specific heat behaviour shows a considerable difference from the result obtained in the previous paper, where only the lowest energetic configuration was considered. The consequences of this result with respect to the configurational properties of polymer molecules near the θ temperature are discussed.
All-Temperature Partition Function from Variationally Optimized Canonical Density Matrix
Authors: Baltin R.
Published: February 2015

For the canonical density matrix C(r, r0,β) a variational ansatz C̄̄f = (1 - f̄) Ccl + f̄ Cgr is made where Ccl and Cgr are the classical and the ground state expressions which are exact in the high temperature (β → 0) and in the low-temperature limits (β → + ∞), respectively, and f̄ is a trial function subject to the restriction that f̄ → 0 for β → 0 and f̄ → 1 for β → ∞. With the approximation that f̄ be dependent only upon β, not upon spatial variables, the mean square error arising when Cf is inserted into the Bloch equation is made a minimum. The Euler equation for this variational problem is an ordinary second order differential equation for f̄=f(β) to be solved numerically. The method is tested for the exactly solvable case of the one dimensional harmonic oscillator.
Variational Formulation for Two-Fluid Plasmas in Gebsch Variables
Authors: Caldas I. L. , Tasso H.
Published: February 2015

A variational principle for two-fluid plasmas is obtained by using Clebsch variables. A Hamiltonian formalism is derived and canonical Poisson brackets are defined.
A Viscosity-Temperature Study for a Glass-Forming-Non Aqueous Electrolyte: Zinc Bromide in Ethyl Acetate
Authors: Nicolas M.
Published: February 2015

The low temperature behavior of solutions of zinc bromide in ethyl acetate has been studied by viscosity measurements and differential thermal analysis. It is shown that the solutions go through a glass transition at temperatures between 100 K and 220 K. With decreasing temperature, η(T) behaves first Arrhenius-like and then obeys the Fulcher relation. A reduction of the viscosity with respect to that of the pure solvent (ηs) gives a family of curves converging to one point at high temperature; if moreover In (η/ηs) is plotted vs. the inverse of the reduced temperature T/Tg, Tg being the glass transition temperature, the plots coincide within 5% for all solutions. A simple relation between the reduced viscosity and the lone entropy is found, since one obtains din (η/ηs)/d (Tg/T) = α (Tg/T - Tg). Comparison is made with the Adam-Gibbs model. The properties of these glass-forming electrolytes are assumed to be due to a "granular" structure which becomes quasi-polymeric at high concentration.
109Ag NMR-Study of the Selective Solvation of the Ag+ Ion in Solvent Mixtures of Water and the Organic Solvents: Pyridine, Acetonitrile, and Dimethyl Sulfoxide
Authors: Mittermaier L. Guinand. K. L. Hobt. E. , Rößler E. , Schwenk A. , Schneider H.
Published: February 2015

In mixtures of water (W) and one of the organic solvents pyridine, acetonitrile, and dimethyl sulfoxide (O), the silver ion forms the following solvate complexes: AgW2, AgWO, and Ag02. The chemical shift of 109Ag is strongly affected by the ligating solvent molecules, and replacing the ligand W by one of the three organic ligands yields a higher Larmor frequency. In solvent mixtures, only a single resonance line has been observed because of rapid chemical exchange. The measured chemical shifts in the range up to 400 ppm are mean values of the chemical shifts of the different solvate species in a given mixture, weighted with their relative concentrations.

The 109Ag chemical shifts were determined for 0.05 to 0.15 molal solutions of AgNO3, as functions of the mole fractions of the solvent components. Using a Gaussian least squares fitting routine, the individual chemical shifts of the Ag+ solvate complexes and the corresponding equilibrium constants were determined. This fit was successful for the whole mole fraction range of DMSO, while in the solvent systems with acetonitrile and with pyridine at higher concentrations of the organic component the chemical shift is influenced by more than two solvent molecules. In these cases equilibrium constants were calculated from chemical shift data for solutions of low mole fraction of acetonitrile and pyridine.
Kinetic and Thermodynamic Study of the Acid-Catalysed Hydrolysis of Diethylmalonate in Dioxane-Water Mixtures
Authors: Asaad Adel N. , Khalil Fayez Y.
Published: February 2015

A kinetic study of the acid-hydrolysis of diethylmalonate in water and dioxane-water mixtures covering the range 0-95% (w/w) of dioxane is reported. The reaction rate is inversely proportional to the organic content of the medium up to about 80% (w/w) then, after passing through a minimum, it becomes directly proportional as the dioxane cosolvent is further added. The kinetic ratio k1/k2 is independent of the solvent composition. The observed activation energies, thermodynamic parameters and radii of the activated complexes along the whole range of solvent composition, for the two consecutive steps of the reaction, are computed. Electrostatic theories favour an interaction in which an ion and a molecular dipole are involved. Application of the reactivity-selectivity principle (RSP) to the present reaction in comparison with that for diethylsuccinate. under different conditions of temperature and solvent composition, is presented.
The Ground and Ionised States of S2N2; Ab initio Configuration Interaction Studies of the UV-Photoelectron Spectrum
Authors: Palmer Michael H.
Published: February 2015

Ab initio CI calculations using a large spd-basis with polarisation functions have been obtained for the ground state of S2N2 and for many doublet state radical cations of each symmetry. All valence shell electrons were considered in the CI, leading to markedly lower energies than previous work. All doublet states down to about 20 eV have probably been found - this leads to a more general description of the UV-photoelectron spectrum, but the principal IP's are still assigned according to our previous work. Some deficiencies in the Green's Function/Tam Dancoff Method have been noted. The principal groups of shake-up states seem to agree with weak structure in the observed spectrum.
Kristallstruktur und Schwingungsspektrum des Praseodym-ortho-Thiophosphates PrPS4 / Crystal Structure and Vibrational Spectrum of PrPS4
Authors: Wibbelmann Claus , Brockner Wolfgang , Eisenmann Brigitte , Schäfer Herbert
Published: February 2015

PrPS4 crystallizes in the tetragonal system, space group I41/acd with the lattice constants a= 1091.4(5) pm. c = 1936.1(8) pm. In the structure there are slightly distorted PS3-
4 tetrahedra as discrete structural units, placed along the b-axis. Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned rangewise by factor group analysis and the Td-D4h-correlation. The Raman data of rare-earth ortho thiophosphates LnPS4 with Ln = La, Ce, Pr, Nd, Sm, Tb and Tm are given in a line diagram.
Quantenphysikalischer Zustandsraum im Kontinuum / Quantum physical state space in continua
Authors: Bopp Fritz
Published: February 2015

As previously shown, quantum physics for single pairs of creation and annihilation processes may be derived from first principles. Quantum physics at all can be therefore considered as an interplay of such elementary processes. This is easily possible if the number of pairs of processes is finite. Difficulties arise only for infinite numbers.

The difficulties are similar to those occurring in the derivation of the equation for an oscillating string from that for an oscillator chain. It is true that the spectra of both systems are not continuously connected. However, a weaker theorem is more important: The chain eigenvalue of each order converges to the string one of the same order for an infinitely growing number of oscillators of a certain kind. Therefore both systems are continuously connected in the sense of semiconvergency.

Exhausting the space continuum with a sequence of lattices equably becomming infinitely large and fine, the infinitely dimensional Hilbertspace is steadily connected with the finitely dimensional one in the sense of semiconvergency. It will be shown that the Hilbert spaces in the sequence of lattices yield the suitable tool for quantum physics as an interplay in the mentioned sense. This kind of Hilbert space, the so-called rational one, must be preferred in physics rather than the real one introduced by Hilbert, since all theories in physics are based on a finite number of data.

In particular, we formulate Dirac's equation in the rational Hilbert space. It is shown that, even in quantum physics, a theorem of classical physics remains true, according to which relativity results from certain principles formulating most obvious experiences. We obtain the Lorentz invariant Dirac equation mainly from a modification of Newtons definition II according to which p = Hυ/c2 (instead of p = m υ).
Proton NMR Studies and Lineshape Simulations of the Mesophases of Terephthalylidene -Bis -4 -n-propylaniline (TBPRA) — Evidence for Conformational Changes
Authors: Limmer St. , Findeisen M.
Published: February 2015

From comparison of simulated and experimental spectra in the nematic, smectic-A, and smectic-A phases of TBPrA it can be concluded that there are conformational changes of the molecule giving obviously rise to a continuous variation of the direction of the long molecular axis with respect to a frame of reference connected with a conformation of the molecule that was derived from the crystal conformation of TBBA.
Surface Forces of the Electric Field Induced Flowin Nematic Liquid Crystals
Authors: Grupp J.
Published: February 2015

In thin nematic liquid crystal films with homeotropic boundaries, surface forces are measured that are produced by an electric field induced flow. The sample is placed between two horizontal circular glass disks in a torsion viscosimeter, where a torque is exerted on the upper disk by these surface forces. The evolution of the induced flow is registered via this torque. The time constants of this evolution, the viscosity term γ1 - α2
2/ηc and the elastic constant K3 are determined.
Dissociative Ionization and Metastable Ions of Nitrobenzene and Nitrobenzene-d5
Authors: El-Kader F. H. Abd , Ahmed H. M.
Published: February 2015

The kinetica energy released on the loss of CNO2 from nitrobenzene and deuterated nitrobenzene ions in the second field-free region shows that this loss does not occur as a single-step process.

The apparent heat of formation of the C6H+
5 ion is found to be 270.85 kcal mol-1, which is consistent with the ion having the cyclic structure.
Triplet States in Isotopically Mixed Naphthalene Crystals: High Resolution Optical Spectroscopy
Authors: Doberer U. , Port H.
Published: February 2015

The triplet 0.0 transitions (T1↔ S0) of guest and host in various isotopically mixed naphthalene crystals, with guest states below and above the host exciton band, are investigated applying both laser excitation spectroscopy and phosphorescence emission spectroscopy. Guest monomer and aggregate spectra are analyzed at helium temperatures (1.6-4.2 K) with regard to line positions, splittings, polarizations and intensities. Shift and broadening of the host Davydov components are studied as a function of the guest concentration (at 1.6 K). In particular, the analysis provides precise values for the individual isotopic shifts U0 and the exciton band structure parameters including the critical isotopic shift. Site splitting is spectrally resolved for several monomers and also for the AB-dimer of 1,4-Nd2 in Nd8
Structure Investigation into Acetonitrile Solutions of Mg(ClO4)2 by Neutron Diffraction
Authors: Hoppe U. , Matz W.
Published: February 2015

The structure of acetonitrile solutions of Mg(ClO4)2 at two concentrations (c = 0.38 mole/1 and 0.74 mole/1) is studied by neutron diffraction. The results are interpreted by a simple structure model. A good description is achieved for c = 0.38 mole/1 by an octahedral surrounding of Mg2+ by acetonitrile molecules. For the higher concentration the fit results in a mixture of tetrahedral and octahedral surroundings
Semiempirische Rechnungen zur Protonenaffinitat unverzweigter aliphatischer Amine / Semiempirical Calculations on the Proton Affinity of Unbranched Primary Aliphatic Amines
Authors: Raabe Gerhard , Fleischhauer Jörg
Published: February 2015

The experimental gasphase proton affinities of some alkylamines are found to correlate with the Mulliken charges on the NH3-groups of the corresponding ammonium-cations as calculated by the semiempirical MINDO/3- and MNDO-method rather than with the electron density at the nitrogen-atom or the NH2-group of the corresponding Amines.

As can be seen from the charges of the NH2-groups of the amines, the alkyl-chains do not exhibit a general positive inductive effect. It is found that the amount of electron density transferred to an attacking proton increases with the length of the alkyl-chains. This effect is similar to the so-called inductomeric effect introduced by Ingold
The Relaxation Time of the Orientation Polarization and its Influence on the Luminescence Intensity Distribution*
Authors: Kawski A.
Published: February 2015

The characteristic relaxation time τR of the orientation polarization of polar solvent molecules around polar luminescent molecules influences the spectral emission distribution depending on τF > τR or τF ≦ τR. This is shown on the luminescence of the polar molecules 4-isocyanate- 4'-dimethylamino-transstilbene (CDS), 4-isocyanate- 4'-methoxy-trans-stilbene (CMS) and 4-isocyanate- 3',4'-dimethoxy-trans-stilbene (CDMS) (having a very short lifetime τF < 10 ps) in chlorobenzene
Foundations of a Theory Concerning Hydrogen Centres in Metals
Authors: Wahl F. , Duscher R. , Göbel K. , Maichle J. K.
Published: February 2015

The present work is an attempt to treat hydrogen storage in metals with the aid of field theoretical methods. Starting with the many-body Schrödinger equation, an adiabatic decomposition yields an electronic system, a protonic system and a host lattice system. We define a storage energy consisting of a lattice contribution and an electronic part. The latter one will be evaluated by The New Tamm-Dancoff (NTD) procedure. This formalism is a method to compute differences of eigenvalues in quantum mechanical problems. As an example we derive a one-particle equation describing a single hydrogen atom in a metal crystal.
Correlation Functions in the Isotropic Phase of Nematics
Authors: Govers E. , Vertogen G.
Published: February 2015

The orientational correlation functions in the isotropic phase of nematics are calculated starting from the expression of De Gennes for the free energy density of this phase.
Phase Transition Studies in PMBAB and PEBAB
Authors: Pisipati V. G. K. M. , Rao N. V. S.
Published: February 2015

The variation of density and ultrasonic velocity with temperature in N-(p-methoxybenzylidene)- p-aminobenzonitrile (PMBAB) and N-(p-ethoxybenzylidene)-p-aminobenzonitrile (PEBAB) are presented. The density jumps and thermal expansion coefficients suggest the nematic-isotropic transition of both compounds to be of first order. The adiabatic compressibility βad, molar sound velocity Rn and molar compressibility Aw are computed. The contribution of a methylene unit to the molar volume is found to be higher than literature values. The anomalous ultrasonic velocity dip at the nematic-isotropic transition for both compounds is found to be high; the value is many times those found for other nematic-isotropic or nematicsmectic A transitions.
Bound State Solutions of the Klein-Gordon Equation for Strong Potentials
Authors: Fleischer Wolfgang , Soff Gerhard
Published: February 2015

We explicitly construct normalized solutions of the Klein-Gordon equation for various types of attractive potentials. Our computed binding energies of several short- and long-range potentials are compared with results published by different authors. Special emphasis is laid on the determination of critical potential strengths, i.e. the onset of spontaneous pair creation of spin-0 particles. In the vicinity of these critical values the single-particle interpretation breaks down. The phenomenon of simultaneous particle and antiparticle binding in a short-range potential is investigated.
Kinetics and Mechanism leading to Dimeric Redox Products of 4-Nitrosobenzaldehyde in Alkaline Dioxane-Water Media
Authors: Riad Y. , Asaad Adel N. , Gohar G.-A. S. , Abdallah A. A.
Published: February 2015

A Cannizzaro disproportionation reaction of 4-nitrosobenzaldehyde (I) and sodium hydroxide in dioxane-water media is kinetically studies by UV-Vis. absorption spectroscopy. The reaction did not give the expected products, namely 4-nitrosobenzyl alcohol and 4-nitrosobenzoic acid, but gave equimolecular quantities of 4,4′-diformylazoxybenzene (II) and 4,4′-dicarboxyazoxybenzene (III) and was found to exhibit third-order kinetics, second-order in aldehyde and firstorder in base. The rate constants as well as the activation thermodynamic parameters were calculated for different temperatures and different dioxane-water compositions, and discussed on the bases of dielectric constant, viscosity and heat of mixing of the medium components. The rate determining step is a hydride ion transfer from the adduct (formed from the attack of one hydroxide ion on molecule of I) to another molecule of I. A mechanism is given to explain the formation of the end reaction products.
The Influence of the Chemical State on K x-RayIntensities
Authors: Rose T. , Borchert G. L. , Schult O. W. B.
Published: February 2015

The x-ray intensities of the Kβ and KO lines relative to the Kα1, transition were measured with high accuracy for the pairs La2O3-La, SmS-Sm, Sm2O3-Sm and Ta2O5-Ta. The Kβ13 and Kβ24 lines do not show significant intensity shifts. However, the intensity of the KO line is in La2O3 (15.0 ±4.7)% higher, in SmS (6.9 ± 2.7)% lower and in Ta2O5 (12.5 ± 8.7)% higher than that emitted from the corresponding metal. These results can be reproduced by Dirac-Fock-calculations, where the KO-intensities show a typical dependence on the quantum numbers of the valence electrons. The observed shifts indicate a 4f-5d hybridization or promotion in metallic Lanthanum and suggest the missing of a 4f electron in metallic Samarium compared to the free atom.
Search for Streaks in Electron Diffraction Patterns of Strontium Titanate
Authors: Arenas German , Geiger Jürgen
Published: February 2015

Streaks were found in the electron diffraction diagrams of ion-etched single-crystalline SrTiO3 for beam incidence parallel to the [111] direction. The streaks correspond to intensity walls perpendicular to the [ζ00] directions in agreement with the theoretical prediction. The soft phonons seem not to contribute significantly to the streaks.
Influence of Internal Heavy Atoms on the Spectroscopic Properties of 9-Acetoxy-10-Phenylanthracene Derivatives
Authors: Heidt Janina R.
Published: February 2015

Absorption and fluorescence spectra, fluorescence quantum yields and decay times have been measured for new derivatives of 9-acetoxy-10-acetoxyhalogenophenylanthracene in dioxane. It is found that the strength of the absorption transition decreases with increases atomic number Z of the halogen substituent whereas the strength of the fluorescence transition is constant with the exception for the fluoro-substituted derivatives. The loss of mirror symmetry between the absorption and fluorescence spectra is more evident for the 10-(4-acetoxy-3'-halogenophenyl)anthracene derivatives than for the remaining compounds. The determined nonradiative electronic relaxation rate constant and "dark reactions" quantum yield increases with increasing Z value. These findings are explained on the basis of the spin-orbit coupling enlarged by the heavy substituent and through perturbation of the functional groups, which causes different changes of the molecular geometries in the S0 and S*1 states, respectively.
Photoluminescence of [22]Paracyclophane and p-Xylene in the Presence of Silver Ions
Authors: Zander M.
Published: February 2015

Phosphorescence spectra and phosphorescence lifetimes of [22]paracyclophane (I) and p-xylene have been measured in ethanol glass at 77 K in the presence of silver Perchlorate at various concentrations. From the results it is concluded that the ground state complex formed with AgClO4 is much more stable in the case of the cyclophane than with p-xylene. The results would indicate that under the conditions used [22]paracyclophane forms a 1:1 complex with AgClO4 with the silver ion being located within the cyclophane cage. Fluorescence quenching measurements in fluid solution at room temperature using ethyl bromide and AgClO4 as quenchers support this assumption.
Order-Disorder Transitions in the Vanadium-Hydrogen System Measured by Perfect-Crystal Neutron Small-Angle Scattering
Authors: Mikšovsky A. , Rauch H. , Seidl E. , Wächter W.
Published: February 2015

The solubility limits for hydrogen in vanadium were determined using small-angle neutron scattering. In addition, the neutron transmission in dependence of the hydrogen concentration at 170 °C (pure α-phase) and at 20 °C (α + β-phase) was measured. The total cross section of the proton in the α-phase was found to be nearer to the free than to the bound value. The Guinier-approximation is used to examine the small-angle scattering of precipitates in the β-phase V2H. The features of perfect-crystal neutron small-angle scattering for the precise transmission measurement and for the investigation of the very small Q-range are demonstrated.
Raman-Spektren von geschmolzenem Thalliumhexathiometa-diphosphat Tl2P2S6
Authors: Becker Robert , Brockner Wolfgang
Published: February 2015

Raman spectra of molten Tl2P2S2 and of Alkali bromide-Tl2P2S6 melt mixtures have been recorded. The spectra are interpreted from the temperature dependent dimer-monomer equilib­rium P2S2-
6 ⇄ 2 PS-
3. We propose the planar structure [xxx] (D3h symmetry) with delocali­zation of charge for the uncommon PS-
3 anion. It is pointed to an analogy of P2S2-
6 and the isoelectronic Al2Cl6. Lewis acid-base equilibria are formulated for molten Me2S-phosphorus sulfide systems.
Subchromophore Recognition in Some New Luminophores
Authors: Fratev Filip , Enchev Venelin , Nikolov Petar , Polansky Oskar E.
Published: February 2015

The character of electronic transitions in the UV-VIS spectra of some organic luminophores has been studied by means of the Pars Orbital Analysis (POA) of electronic excitation. The analysis allows to classify the compounds investigated as luminophores with stilbene (ST) or bisstyrylbenzene (BSB) subchromophores.
Rotational Excitations and Tunnelling of Non-Equivalent Methyl Groups in Pb(CH3)4
Authors: Prager M. , Müller-Warmuth M.
Published: February 2015

Rotational tunnelling and librations of the methyl groups in tetramethyllead have been measured as a function of temperature by inelastic neutron scattering. Tunnel splittings of 74 μeV and 30.7 (ieV and librational peaks at 3.6 μeV and 10.2 μeV have been observed. The data show that Pb(CH3)4 is isomorphous to Sn(CH3)4 with a space group Pa3, Z = 8 and the molecules at c-sites. Rotational potentials for both types of inequivalent CH3 groups are derived and used for the explanation of NMR-T1 measurements.
Chaos as a Limit in a Boundary Value Problem
Authors: Kahlert Claus , Rössler Otto E.
Published: February 2015

A piecewise-linear. 3-variable autonomous O.D.E. of C0 type, known to describe constantshape travelling waves in one-dimensional reaction-diffusion media of Rinzel-Keller type, is numerically shown to possess a chaotic attractor in state space. An analytical method proving the possibility of chaos is outlined and a set of parameters yielding Shil'nikov chaos indicated. A symbolic dynamics technique can be used to show how the limiting chaos dominates the behavior even of the finite boundary value problem.
An 27Al and 13CN.M.R. study of the Complexes between Al3+ and Various Organic Molecules Containing the Amide Group in Concentrated Aqueous Solution
Authors: Caminiti Ruggero , Crisponi Guido , Nurchi Valeria , Lai Adolfo
Published: February 2015

The complexation between Al3+ and urea, formamide, acetamide and their alkyl derivatives were investigated by 27Al and 13C N.M.R. spectroscopy. A fitting procedure allowed to obtain the populations of each bound and free form of Al3+. From these data the equilibrium parameters were calculated in a direct way. and the results discussed in terms of substituent effects on the interaction phenomena. In this respect the steric hindrance, the polarization of the electronic charge and the hydrophobic character of the alkyl groups were considered as affecting factors.
Charge Transfer Complexes of Aromatic Nitrocompounds with Disubstituted Naphthalenes. I.Spectroscopic Investigation of the Donor Behaviour of the 2,6- and 23-Dimethylnaphthalene
Authors: Abdel-Kader M. H. , Issa R. M. , Ayad M. M. , Abdel-Mottaleb M. S.
Published: February 2015

The charge transfer complexes of 2,3- (I) and 2,6-Dimethylnaphthalenes (II) as electron donors with tri- and di-nitrobenzenes as electron acceptors are prepared and investigated by element analysis, IR. 1H nmr and electronic absorption spectroscopy. The results showed that I yields CT complexes of 1:1 type only while II is capable of forming 1 : 1 and 1 : 2 (donor: acceptor) compounds. The spectral characteristics of the CT complexes are pointed out and discussed. The difference in the donor behaviour between I and II is explained in the light of PPP-MO calculations.
Determination of Ultrasonic Absorption and Velocity and the Derived Thermodynamic Properties of Pure and Binary Molten Salts
Authors: Fuchs W. , Richter J.
Published: February 2015

The absorption and velocity of ultrasonic waves in molten salts are studied with an improved pulse method, which allows an exact and immediate measurement of the runtime of the impulses and of the amplitude of the recorded signals.

The measurements are performed in the pure molten salts sodium nitrate, potassium nitrate, and silver nitrate as well as in the three binary mixtures of these salts in the temperature range between 430 K and 620 K at various compositions. All values are measured at 27.789 MHz, the resonance frequency of the quartz transducers being used.

From the ultrasonic velocity, together with the expansion coefficient and the specific heat capacity, the adiabatic compressibility, the adiabactic constant, and the Rao's constant have been calculated. From the ultrasonic absorption and velocity results the volume viscosity, which can be referred to the structural relaxation of the molecules in the fused salts investigated here.
Eine „fehlende" Gitterschwingung in Pyrit - beobachtet mit Hilfe der ATR-Methode / Observation of a "missing" mode in pyrite by the ATR-method
Authors: Behmer M.
Published: February 2015

The present work reports the observation of one of the two "missing" modes in FeS2 (pyrite) by means of the ATR(attenuated total reflection)-method as a supplement to a paper by Lutz, Kliche, and Haeuseler (1981). The two highest polariton dispersion branches ω=ω (k) have also been measured with this technique.
Lα Emission from Low-Energy Collisions H+ +Ar, H2
+ + Ar, H+ +H2
Authors: Ottinger Ch. , Yang M.
Published: February 2015

Absolute integral cross sections for Lα emission from the title collision systems are reported for energies from threshold to several hundred eVCM. They are discussed in comparison with the systems Ar+ + H, H2.
Generation of Intense Black-Body Radiation in a Cavity by a Laboratory Pulsed Power Source
Authors: Pakula R. , Sigel R.
Published: February 2015

Pulsed laser and particle beams afford possibilities of generating intense black-body radiation in small cavities of high-Z material. The radiation confinement in the cavity is investigated on the basis of the non-stationary hydrodynamic equations including radiative heat transfer. It is estimated that with a pulse energy of 1012 erg a temperature of about 5 x 106 K may be obtainable.
Common Behaviour of NMR Parameters of 27Al, 69Ga, 71Ga, and 115In in Aqueous Solutions
Authors: Kodweiß J. , Köhnlein D. , Kössler G. , Lutz O. , Messner W. , Mohn K. R. , Nolle A. , Nothaft G. , Ruppert P. , Steinhäuser N. , Zepf D. , Haid E. , Schich W.
Published: February 2015

The behaviour of the NMR parameters line width, longitudinal relaxation time, and chemical shift o f 27Al, 69Ga, 71Ga, and 115In has been investigated in aqueous solutions as a function of salt and concentration of added acid or base. A similar behaviour for the NMR parameters o f these nuclei has been found.
Die Austausch-Kopplung von Gd3+- und Cr3+-Ionen in paramagnetischem GdCrO3
Authors: Dräger K.
Published: February 2015

Polycrystalline samples of stoichiometric GdCrO3 have been investigated by ESR at 9.4 GHz. In the temperature range between 175 K and 520 K one broad absorption with a Lorentzian line shape and a g-factor of 2.024 has been observed. Attributing the absorption exclusively to the Gd -ion it can be shown that the temperature dependence of the ESR-intensity follows the predictions of a cluster-model. The energy describing the coupling of a single Gd3+-ion to the surrounding Cr3+-ions is found to be ΔE(Gd) = 170 cm-1. Taking advantage of the similarity within the orthochromites it is possible to determine at the same time the exchange - coupling of Cr3+-ions to their identical nearest neighbours as ΔE(Cr) = 293 cm-1. The relative strength of these couplings given by 0.60 is compatible with other experimental issues.
Homology of a Structurally Stable Chemical Rearrangement
Authors: Fernández Ariel
Published: February 2015

The structural stability in the sense of Adronov and Pontriagin is proved to be a property of any rearrangement occurring in a single electronic state sheet of the potential energy surface if such a rearrangement involves two internal degrees of freedom. It is then shown that features of no dynamical significance (the paths of steepest descent joining critical configurations) determine completely those of dynamical significance: The topology of the set of paths of steepest descent determines the triangulation of the nuclear configuration space which is rigorously derived from homology theory.
Spatially Inhomogeneous Plasma with Negative Ions and Modified KdV Equation with x Dependent Term
Authors: Roychoudhury R. K. , Bhattacharrya Sikha
Published: February 2015

We have derived a modified KdV equation with x dependent term in the case of a spatially inhomogeneous plasma using the stretched co-ordinate system by Asano. Exact and perturbation solutions derived from inverse scattering method are discussed.
Die Wellenlängen der L-Serie des Röntgen-Spektrums von Technetium
Authors: Kleykamp H.
Published: February 2015

The L series of the X-ray spectrum of technetium was measured between 400 and 600 pm using the linear spectrometer of an X-ray microanalyzer. The wavelengths and relative intensities of ten identified lines are given.
On the Stark Broadening of Singly Ionized Argon Lines
Authors: Dimitrijevic’ M. S.
Published: February 2015

Using a semi-classical formalism which includes Debye shielding, Stark broadening parameters of various components within the 4 s 2P - 4 p ´ 2P0 multiplet and the 4 p - 4 d (2P 0 - 2P, 2D0 - 2 P, 2D0 - 2D) supermutiplet of Ar II are computed. We show that when various components of a multiplet (supermultiplet or transition array) are broadened inequally by an embedded closelying perturbing level, use of a perturber param eter cut-off at the Debye length can restrain the calculated differences between Stark widths within the multiplet.
On the Discretization of Certain Operator Field Equations
Authors: Vázquez Luis
Published: February 2015

Two new explicit finite difference schemes are proposed for certain operator field equations in a lattice.
SU2 × SU2 Spin Flavor Subquark Model of Family Structure
Authors: Wolf C.
Published: February 2015

A simple spin-flavor model for the substructure o f the 6 known quarks is proposed which is able to predict the correct Dirac magnetic moments if we interpret the quark masses as constituent masses. The addition of other degrees of freedom is proposed to facilitate the prediction of the correct mixing angles.
Quantenchemische Rechnungen an Stickstoffbasen. Teil 5*: Semiempirische Rechnungen zum Zusammenhang zwischen der elektrostatischen Energie, der Polarisationsenergie und der Protonenaffinität aliphatischer Amine
Authors: Raabe Gerhard , Niephausund Herbert , Fleischhauer Jörg
Published: February 2015

The finding o f Morokuma et al., that polarization rather than electrostatics determines the order of the protonaffinities of ammonia and its mono-, di-, and trimethyl-substituted derivatives, is compared with the results of semempirical methods. We used atomic polarizabilities, charges and geometries calculated by the MINDO /3-method to determine the polarization and the electrostatic part of the energy of interaction between an approaching proton and fourteen bases. Further we used the polarizability increments found by us recently, and those of Miller and Savchik in the calculation of the polarization part. Use of the MINDO/3-FP polarizabilities or the polarizability increments leads to polarization energies which correlate with the ab initio results o f Morokuma in an excellent or satisfying manner, respectively. Moreover the polarization energies calculated with the M IN D O /3-FP data are found to correlate with the protonaffinities of the amines under consideration. In accordance with the ab initio results cited above, the electrostatic part o f the interaction energy becomes more and more positive if one replaces the hydrogen atoms in ammonia by methyl or ethyl groups successively. The reason for this counterintuitive effect is analyzed in the case of ammonia and the methylamines.
Rotational Spectrum and 14N-Quadrupole Coupling Constants of Orthofluorobenzonitrile, a Microwave Fouriertransform Study
Authors: Böttcher Olaf , Sutter Dieter H.
Published: February 2015

Seventyseven a-type rotational transitions of Orthofluorobenzonitrile were observed and assigned in the 8 - 25 GHz frequency range. The spectrum was recorded using the high resolution microwave Fourier transform spectrometer constructed at Kiel University. For most transitions the l4N quadrupole hfs patterns could be fully resolved. The spectroscopic constants obtained by a fit to the observed hfs-center frequencies and to the observed hfs multiplet splittings are: A = 2940.745(12) MHz, B = 1512.699(1) MHz, C = 998.633(1) MHz (rotational constants) and Χaa = - 4.114( 17) MHz, Xbb - Xcc= 0.383(34) MHz (14N quadrupole coupling constants). The rotational spectrum of a low lying vibrational state could be also assigned.
P-Typ-verzögerte Fluoreszenz von 1-Naphthyl-9-carbazyl-methan
Authors: Zander Maximilian
Published: February 2015

P-tvpe Delayed Fluorescence o f 1-Naphthyl-9-carbazyl-methane

At 77 K 1-naphthyl-9-carbazyl-methane adsorbed on filter paper shows predominantly delayed fluorescence o f the carbazole chromophore. The experimental findings are in agreement with the assumption that the carbazole chromophore after excitation by light absorption becomes first deactivated by intramolecular triplet-triplet energy transfer and then re-excited in a two-step mechanism including intermolecular naphthalene triplet-triplet annihilation and intramolecular singlet-singlet energy transfer from the naphthalene to the carbazole chromophore.
Kerr Orientation Influence on Excited State Absorption Measurements
Authors: Menzel Ralf , Rapp Werner
Published: February 2015

The possible influence of a strong nonresonant laser field on the orientation o f dyes in solution is discussed as a potential source o f measuring errors in excited state absorption analysis. The results o f investigations on some typical samples suggest that, fortunately, the effect is very small.
Zur Kinetik von Photofolge- und Photoparallelreaktionen
Authors: Ursin B. , Kleindienst H.
Published: February 2015

The knowledge of the absorptivity of all components at the irradiation wavelength and the partial quantum yields is indispensable for the complete kinetic interpretation of a photoreaction.

For the mechanism

two iterative methods are recommended if the reaction products are isolable not at all or only in low yields.

The algorithms are particularly suitable for sensitive stilbenes and azastilbenes in oxidizing media.
Zur Kinetik von Photofolge- und Photoparallelreaktionen.
Authors: Ursin Bernd , Kleindienst Heinz
Published: February 2015

For all types of the photoconsecutive reaction

with a (0) = a0 b(0) = c(0 ) = 0 an algorithm is recommended to calculate the absorptivity of B (inisolable) and the partial quantum yields φ1, φ2, φ3 and φ4.

The method depends on the so-called formal integration of the kinetic equations and the best fit of the unknowns to the absorbance-diagram and the kinetic constants.

A comparison with other optim ization methods for nonlinear equations is given.
Relativistic Electron-Positron Gamma Ray Laser
Authors: Winterberg F.
Published: February 2015

The prerequisite for an efficient electron-positron gamma ray laser, which is the rapid formation o f a dense electron-positron plasma in a time shorter than the time for pair annihilation, is ideally fulfilled in a relativistic electron-positron superpinch. Because the cross section for annihilation decreases quadratically with the center o f mass energy, the time requirements otherwise imposed, are greatly relaxed. A relativistic electron-positron pinch can collapse under a complete population inversion into a very dense state possessing the form o f a long filament, just as it is required for a gamma ray laser. The gamma ray energies are the total center of mass energies, which can be much larger than the electron-positron rest mass energies.
A Spin 3/2 20-dimensional Wave Equation with Definite Charge and its Propagation in an External Electromagnetic Field
Authors: Koutroulos C. G.
Published: February 2015

The charge of a spin 3/2, 20-dimensional wave equation of the Gel’fand-Yaglom form based on the representation (1/2, 3/2) ⊕ (- 1/2, 3/2) ⊕ (1/2, 5/2) ⊕ (- 1/2, 5/2) ⊕ (1/2, 3/2) ⊕ (- 1/2, 3/2) and its propagation behaviour in an external electromagnetic field are studied, and it is shown that its charge is definite but its propagation is not causal.
Matrix Formulation of the Subsidiary Conditions of the Second Kind for the Pauli-Fierz Wave Equation
Authors: Koutroulos C. G.
Published: February 2015

It is demonstrated, using the Pauli-Fierz wave equation as an example, that the subsidiary conditions o f the second kind for a first order wave equation can be expressed in matrix language.
11B NMR Investigations of Borate Esters in Aqueous Solutions and Wine
Authors: Lutz O. , Veil E. , Brändle U. , Helber H. , Kämmerer E. , Scheiter A.
Published: February 2015

11B NMR studies have been performed in dilute solutions of boric acid resp. borate and some typical hydroxy-carboxylic acids as a function of pH. Typical chemical shifts have been found for the esters occurring at the different ranges of pH. The origin of the two 11B NMR signals observable in wine could be determined.
A Dissipative Model of Plasma Equilibrium in Toroidal Systems
Authors: Wobig H.
Published: February 2015

In order to describe a steady-state plasma equilibrium in tokamaks, stellarators or other non-axisymmetric configurations, the model of ideal MHD with isotropic plasma pressure is widely used:

0 = - ∇p + j x B .

The ideal MHD-model of a toroidal plasma equilibrium requires the existence of closed magnetic surfaces. Several numerical codes have been developed in the past to solve the three-dimensional equilibrium problem, but so far no existence theorem for a solution has been proved. Another difficulty is the formation of magnetic islands and field line ergodisation, which can only be described in terms of ideal MHD if the plasma pressure is constant in the ergodic region. In order to describe the formation of magnetic islands and ergodisation of surfaces properly, additional dissipative terms have to be incorporated to allow decoupling of the plasma and magnetic field. In a collisional plasma, viscosity and inelastic collisions introduce such dissipative processes. In the model used a friction term proportional to the velocity v of the plasma is included. Such a term originates from charge exchange interaction of the plasma with a neutral background. With these modifications, the equilibrium problem reduces to a set of quasilinear elliptic equations for the pressure, the electric potential and the magnetic field. The paper deals with an existence theorem based on the Fixed-Point method of Schauder. It can be shown that a self-consistent and unique equilibrium exists if the friction term is large and the plasma pressure is sufficiently low. The essential role of the dissipative terms is to remove the singularities of the ideal MHD model on rational magnetic surfaces. The problem has a strong similarity to Bénard cell convection, and consequently a similar behaviour such as bifurcation and exchange of stability is expected.
Shielding and Antishielding of Nuclear Quadrupole Moments
Authors: Sternheimer R. M.
Published: February 2015

The development of the theory of shielding and antishielding of nuclear quadrupole moments is reported. The various contributions to the Sternheimer shielding and antishielding factors are discussed. Also the history of the different calculational techniques is outlined.
ß-NMR Study of the Electric Field Gradient in the Metallic Intercalation Compound LiC6
Authors: Freiländer P. , Heitjans P. , Ackermann H. , Bader B. , Kiese G. , Schirmer A. , Stockmann H.-J.
Published: February 2015

In the layered compound LiC

6
polarized β-active 8Li probe nuclei were produced by capture
of polarized thermal neutrons. Nuclear magnetic resonance spectra of 8Li were recorded via the
β-radiation asymmetry. The
8Li quadrupole coupling constant e2qQ/h , measured in the temperature range T = 5 . .. 500 K decreases with increasing 7 from 45.2(8) to 22.8(4) kHz.
Anomalies in the overall temperature dependence are discussed in terms of phase transitions
proposed for LiC6.