bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Ginzburg-Landau Theory for the Liquid-Solid Phase Transition
Authors: Hess S.
Published: February 2015

The anisotropy of the probability distribution function for the unit vector joining two nearest neighbour atoms is characterized by tensorial order parameters. For cubic symmetry, the most relevant tensor is of rank 4. Starting from an ansatz for the dependence of the (specific) internal energy, volume and entropy; the entropy production is calculated which is caused by a temporial change of the 4-th rank anisotropy tensor. A constitutive law which guarantees that the entropy production is positive leads to a nonlinear relaxation equation. It shows the features typical for a dynamic Ginzburg-Landau theory. The linearized version of the relaxation equation contains an effective relaxation time and a correlation length which exhibit a temperature dependence typical for a mean field theory. For a special case where the anisotropy tensor can be characterized by a scalar order parameter, the nonlinear relaxation equation is studied in some detail. Its stationary and spatially homogeneous solutions are zero and nonzero values for the order parameter depending on whether the temperature T is larger or smaller than the transition temperature. The unordered phase corresponds to a liquid state, the ordered phase to a simple or body centered cubic crystal. The phase transition is of 1st order. There exist also metastable states.
Ion-Solvent and Solvent-Solvent Interactions. X-ray Study of Aqueous Alkali Chloride Solutions
Authors: Pálinkás G. , Radnai T. , Hajdu F.
Published: February 2015

The first neighbour model, FNM, used frequently for the description of hydration has been modified by dropping the assumption that the structure of the "free" solvent is identical with that of the pure solvent. The modified model, FNM2, reproduces the experimental X-ray structure functions of alkali chloride solutions quite well and enables the study of perturbed solvent-solvent interactions. The refined structural parameters reasonably indicate the dependence of the hydration of the alkali cations on their radius and concentration. The hydration of Cl- has been found to be almost independent of both concentration and the type of counter cation.

The model assumes regular symmetry for the first neighbour coordination sphere, but the high rms deviations of the water-water distances within the shells of the aggregates indicate con-siderable individual asymmetries.

A further modification of the FNM will be discussed in a following paper.
129I/127I: a Puzzling Early Solar System Chronometer
Authors: Jordan J. , Kirsten T. , Richter H.
Published: February 2015

We report I-Xe ages and other relevant xenon data for seven ordinary chondrites from H and L-groups of petrologic types 4-6, which were selected on the basis of minimum weathering and shock effects. Nevertheless, no chronological order with respect to the I-Xe ages exists among the different petrologic types. We demonstrate, however, that the degree to which the 1-Xe record is preserved in these chondrites, but not necessarily the age, is dependent on the thermal metamorphic history. In order to explain the lack of chronological order among the chondrites, spatiotemporal variations in the condensation-accretion process or inhomogeneities in the isotopic composition of iodine in the solar nebula is required.
NMR Investigations of 17O, 33S, 95Mo, and 97Mo in Thiomolybdates
Authors: Kroneck P. , Lutz O. , Nolle A.
Published: February 2015

NMR investigations of 17O, 33S, 95Mo, and 97Mo have been used to elucidate the existence and the behaviour of the oxothiomolybdate species, MoO4-nSn2-(n = 0, 1, 2, 3, 4) in aqueous solution. Very large chemical shifts and surprisingly narrow lines have been found for these nuclei in the different species.
The Change in the Prefactor Exponent with Valence for Percolation in 3 and 4 Dimensions
Authors: Duarte J. A. M. S. , Ruskin H. J.
Published: February 2015

The change of the prefactor exponent for restricted valence percolation in 3 and 4 dimensions is shown to occur between valences 2 and 3 as in 2 dimensions. For valence 2 the exponent is SAW-like and after the change it assumes the normal percolative value for each dimension.
Magnetische Eigenschaften der Normaltemperaturform von CsYbO2
Authors: Urland Werner
Published: February 2015

The magnetic behaviour of the normal-temperature form of CsYbO2 has been studied in the temperature range between 2.8 and 251.3 K. Besides at temperatures below about 12 K the magnetic data are well interpreted by means of a model in which the influence of the crystal field is theoretically described by the angular overlap model and the influence of magnetic interaction by the molecular field model. By this the transferability of the angular overlap parameters from one compound to another is tested. The energy values of the crystal-field levels of the 2F7/2 ground state are calculated.
Search for 129Xe in Mineral Grains from Allende Inclusions: An Exercise in Miniaturized Rare Gas Analysis
Authors: Reynolds J. H. , Lumpkin G. R. , Jeffery P. M.
Published: February 2015

A static mass spectrometer, modified by installation of a Baur-Signer (Zürich) ion source and an ion-counting system, was used to detect xenon from single mineral grains from inclusions in the C3 meteorite Allende. The grains were melted in small conical heaters wound from tungsten wire. In almost all cases excess 129Xe from 129I decay was detected, in concentrations varying from < 1000 to 600,000 atoms per microgram. Inferred iodine concentrations increased on the average from pentlandite (0.6 ppb), to hedenbergite (21 ppb), to olivine (92 ppb), to enstatite (203 ppb) to melilite (422 ppb), but vary widely from one grain to another of the same mineral, indicating that the iodine resides in some minor phase which is included “spottily” in the bulk phases over which we had good mineralogical control. About 23,000 atoms of fissiogenic 132Xe, presumably from 244Pu decay, was detected in the largest melilite sample analyzed, but we cannot determine from this study whether the 244Pu is “spotty” like 129I or is uniformly distributed in the melilite. One can foresee that if the samples could be loaded into previously outgassed heater cones, a system such as the one described in this paper would have 132Xe blanks of ~ 50,000 atoms. It is likely that in such a system the detectability for excess Xe achieved in this paper (~ 20,000 atoms) could be substantially improved. We also ran St. Severin troilite, which contains less than ~ 33 atoms of excess 129Xe per microgram, and a single chondrule from Alllegan, wich contains higher concentrations of radiogenic xenon than were previously reported by Podosek from runs on a pile-irradiated sample.
Radial Distribution of Spallogenic K, Ca, Ti, V and Mn Isotopes in Iron Meteorites
Authors: Imamura Mineo , Shima Masako , Honda Masatake
Published: February 2015

Cosmic-ray-produced stable nuclides of Ca (mass number: 42, 43, 44 and 46), Ti (46, 47, 49 and 50), V (50), Cr (50, 53 and 54) and the long-lived nuclides, 40K and 53Mn were determined along the radial axes of the iron meteorites Grant and Treysa. Grant was extensively examined and the results compared with rare gas data. Although Treysa does not include enough samples to allow detailed analysis, the depth profile shows typical features for a small meteorite.

The results were compared with calculated profiles of 40K, 49Ti and 53Mn using thick bombardment data. The approximate pre-atmospheric radii of Grant and Treysa were determined to be 30 cm and 14 cm, respectively. The effect of space erosion was also estimated by comparing the data of 49Ti and radioactive 53Mn in Grant and Treysa with the calculated patterns. It is suggested that space erosion of both meteorites is small (≲ 0 . 8 Å /y ) during the cosmic-ray exposure of several hundred million years.
Geometrie Unification of Classical Gravitational and Electromagnetic Interaction in Five Dimensions: a Modified Approach
Authors: Osterhage Wolfgang W.
Published: February 2015

A unification of the gravitational with the electromagnetic interaction within a classical framework is proposed. It is based on a V5-geometry, with x5 = q/m. The sole source term is mechanical stress energy, positioned along x5. The trajectories of testbodies are placed in V4 (x5 = const)-slices. The final field equation couples a geometric G-tensor to mechanical stress energy, its momentum with respect to x5 and the change of this momentum with proper time τ.
The Rotational Zeeman Effect of Nitrosylfluoride
Authors: Rohwer F. , Guarnieri A.
Published: February 2015

The rotational Zeeman effect of low J transitions of Nitrosylfluoride in the centimetre and millimetre waveranges has been investigated with fields up to 24 kG.

g-Factors with signs could be determined using the effect of the nitrogen quadrupole coupling interactions. A value for the partial susceptibility contribution of the nitrogen -N= has been estimated.
Electrochemical Determination of Phase Diagrams and Thermodynamic Data of Multi-Component Systems
Authors: Weppner W. , Li-chuan Chen , Piekarczyk W.
Published: February 2015

The coulometric titration technique is extended to treat general cases of systems of any number of components. Complete equilibrium phase diagrams and thermodynamic properties are obtained from readily and precisely measurable electrical quantities, employing only a small number of samples. General equations are derived which directly relate the cell voltage to the standard Gibbs energies, enthalpies and entropies of formation of all phases involved without the necessity of considering specific cell reactions. The application of the technique to the ternary system Cu-Ge-O is demonstrated.
Magnetic and Quadrupole Relaxation in Aqueous BeF2-Solutions
Authors: Jena H. , Kreische W. , Maar H. U. , Niedrig H. , Reuter K. , Wrobel B.
Published: February 2015

In aqueous BeF2-solutions of different concentrations and therefore different viscosities the magnetic relaxation time T1 was measured as a function of the viscosity over a wide range by pulsed NMR-technique. For small viscosities a linear dependence of T1 on the viscosity was observed as predicted by theoretical calculations. Since the ground state spin of 19F is I = 1/2, the quadrupole moment vanishes. For observing quadrupole relaxation of the F-nuclei, one has to use an excited level. With the time differential perturbed angular distribution method (TDPAD) we observed the quadrupole relaxation time TRel of 19F in aqueous BeF2-solutions.
On Graph Theoretical Polynomials of Annulenes and Radialenes
Authors: Gutman Ivan
Published: February 2015

Three graphic polynomials of annulenes and radialenes are examined, namely the matching polynomial, the characteristic polynomial of the Hückel graph and the characteristic polynomial of the Möbius graph. Several relations between them are obtained. These six polynomials and their zeros are mutually closely related.
Der Einfluß lokaler Konzentrationsfluktuationen in binären flüssigen Mischungen von CH3I und CDCl3 auf das Profil von Molekülschwingungs-Banden
Authors: Döge G. , Arndt R. , Buhl H. , Bettermann G.
Published: February 2015

The Raman band shapes of ν1 of CDCl3 and CH3I in the pure liquids and their mixtures are studied. The CH3I mode shows a broadening in the mixtures with a maximum at a mole fraction of about 0.5, whereas the ν1 band of CDCl3, shows a splitting in the mixture. The different behaviour of the two Raman bands is discussed briefly.
Diffusion Coefficients of Aromatic Hydrocarbons in Their Lowest Triplet State: Anthracene in Hexane, Octane, Hexadecane, Perfluorohexane, and Methylcyclohexane; Pyrene and 9,10-Di-phenylanthracene in Hexane
Authors: Meyer E. Georg , Nickel Bernhard
Published: February 2015

An experimental method is described which allows the determination of the diffusion coefficient D of an aromatic hydrocarbon in its lowest and metastable triplet state T1 with an absolute accuracy of ±5%. D was determined at 25 °C. With anthracene the temperature-dependence of D was measured from 0°C to 60°C in hexane and from 20°C to 89°C in hexadecane; it was found to be in good but not perfect agreement with the Stokes-Einstein equation. With the investigated systems, D of molecules in T1 is estimated to be at most 10% smaller than D of molecules in the ground state. No evidence for the formation of triplet excimers was found. Some applications of the method are proposed, and in this connection some questions concerning the kinetics of diffusion-controlled reactions of molecules in T1 and the existence of triplet excimers are discussed.
Zur Diffusionskinetik in Ionenaustauscherharzen Selbst-und Austauschdiffusion von Alkali-und Erdalkaliionen / The Diffusion Kinetic in Ionic Resin Exchangers. Self- and Exchange-Diffusion of Alcaliions
Authors: Miekeley N. , Fernandes P. C. S.
Published: February 2015

Heterogeneous isotope exchange rates of Na+, Ca+, Ba2+ and Sr2+ in mono-and biionic resin exchangers (Merck I) have been measured under conditions where diffusion is rate determining. For the self-diffusion of Na+, Ba2+ and Sr2+ linear Dt/r2 - f(t)-curves are obtained. Cs-isotope exchange shows non-ideal diffusion kinetics. In mixed Ba-exchangers the self-diffusion coefficients of Ba2+ and Sr2 depend on the ionic composition of the exchanger phase. Ion exchange rates have been measured for Ba/Sr2+ -exchange and its reversal. Computed curves are presented using Helfferich’s theory of ion exchange and an extended treatment with activity correction terms and concentration dependent self-diffusion coefficients. Computed and experimental curves are discussed.
On the Influence of p-Nitroacetophenone on Radiation-Induced Molecular Size Changes of DNA
Authors: Washino K. , Schnabel W.
Published: February 2015

DNA has been irradiated in aqueous solutions with 16 MeV electron pulses (duration: 50- 100 ns). In the presence of p-nitroacetophenone (PNAP) the light scattering intensity (LSI) increased after the pulse in Ar- and 02-saturated solutions indicating intermolecular crosslinking. The LSI increase was greatest in Ar-sat. solutions containing t-butanol (1 mol/1). In the absence of PNAP and t-butanol DNA was degraded as indicated by a decrease of LSI. The results contribute to the understanding of radiation-induced reactions, DNA undergoes in the presence of sensitizers of high electron affinity
Photoelectric Determination of V0-Values in Solid Rare Gases
Authors: Zdrojewski W. von , Rabe J. G. , Schmidt W. F.
Published: February 2015

Electronic conduction state energies Fo were measured by photoelectric effect for solid xenon (F0 =— 0.57 ± 0.05 eV, 160 K), solid krypton (F0 = -0.40 ± 0.05 eV, 114 K), and solid argon (Fo =— 0.0 ± 0.05 eV, 82 K). A novel photo cell was employed which eliminated some of the problems encountered in photoelectric work with rare gas solids.
Extension of Dirac's Substraction Formalism to Particles of Finite Size
Authors: Petzold J.
Published: February 2015

Dirac's subtraction formalism is extended to radiating particles of finite size. Irrespective of the charge distribution the equation of motion contains run-away solutions. Hence the radiation reaction is not well described by Ft-
μν.
Energieübertragung zwischen gleich- und ungleichartigen Molekülen in Lösung
Authors: Kawski A. , Szmaciński H.
Published: February 2015

The fluorescence quenching of 2-aminopurine and 2-phenylindole, acting a sensitizers, by 2- aminobenzophenon, acting as acceptor, in viscous solvents (Glycerol + 5% methanol) and its influence on the emission anisotropy (EA) of the sensitizer were investigated. It was found that the relation η/η0 - τ/τ0 (η/η0 the relative quantum yield and τ/τ0 the relative mean lifetime of the excited sensitizer) in this case is good fulfiled. The behaviour of the EA in the investigated acceptor concentration range is discussed.
Ramanspektroskopische Untersuchungen des Systems SeCl4—SbCl5
Authors: Brockner Wolfgang , Demiray A. Fezâ
Published: February 2015

Raman spectra of the solid and molten SeCl4 · SbCl5 addition compound and of some SeCl4-SbCl5 mixtures have been recorded. The structure of the melt can be described by the equilibrium SeCl3
+ + SbCl6
-⇌SeCl4 + SbCl5 lying on the side of the complex ions. SeCl4 decomposes partly into Se2Cl2 and Cl2. Solid mixtures with other stoichiometry contain the 1:1 adduct only and excess SeCl4 (Se2Cl2) or SbCl5, respectively. Such melts are built up by the ionic species SeCl3
+ and SbCl6- mainly and SeCU (dissolved), Se2Cl2 or SbCl5 according to stoichiometry.
On the Internal Motion of Iron Chloride Molecules
Authors: Hargittai Magdolna , Brunvoll Jon
Published: February 2015

The vibrationally averaged structures of the iron chloride molecules may considerable differ from their equilibrium structure as a consequence of low-frequency large amplitude vibrations. Mean amplitudes of vibration and perpendicular amplitude correction terms have been calculated for FeCl2 and FeCl3. Mean amplitudes of vibration have also been calculated for D2h (equilibrium structure) and C2v (vibrationally averaged structure) symmetry forms of Fe2Cl4 and Fe2Cl6-The applicability of normal coordinate analysis for high temperature systems with large amplitude motion is discussed.
Superconductivity and Mixed Conduction
Authors: Welker Heinrich
Published: February 2015

The BCS-formula for the energy gap ΔE is extended to include the magnetic exchange interaction of electrons with holes. With the improved expression for ΔE the transition temperatures of A15-structures are computed and found to be in a satisfactory agreement with the experimental values.
Viscoelasticity Associated with Molecular Alignment
Authors: Hess S.
Published: February 2015

Viscoelasticity as it becomes apparent through the oscillatory motion in flow relaxation experiments is studied theoretically for liquids and liquid solutions containing nonspherieal particles. The coupling between the viscous flow and the molecular alignment which underlies the flow birefringence gives rise to a viscoelastic behavior. The relevant time scale is determined by the orientational relaxation time rather than the (often much shorter) Maxwell relaxation time. The possible relevance of the present theory for the viscoelastic behavior of some dilute aqueous detergent solutions is discussed.
Decay Times Study on the Fluorescence of 4-Methylumbelliferone
Authors: Bauer R. K.
Published: February 2015

Phase, pulse and steady-state measurements of ethanolic solutions of 4-methylumbelliferone with various water and hydrochloric acid contents were performed. A kinetic model is proposed and some parameters are determined.
A Thermogravimetric and NMR Study of β-Aluminas
Authors: Flor Giorgio , Bjorkstam John L. , Villa Marco
Published: February 2015

The Na+ tracer diffusion coefficient and the 27Al NMR spin lattice relaxation time in Na β-alumina display an anomalous temperature dependence near 470 K. These phenomena are related to absorption of water which takes place when the temperature is decreased below 470 K. Water absorption processes in pure and partially substituted β-aluminas are studied by thermogravimetric analysis. Their effects upon conductivity are qualitatively discussed.
Optical Spectroscopy of Mixed Metamagnetic FexCo1-xCl2 Crystals
Authors: Seitz Friedrich , Wood Terence E. , Day Peter
Published: February 2015

Electronic absorption spectra are reported for single crystals of composition FexCo1-xCl2 as a function of temperature from 300 K to 4 K. A broad band at 436 nm is assigned to Fe (II) → Co (II) charge transfer and the temperature dependence of its intensity is related to the magnetic exchange between the ions. The 2T1g(2H) excitation of Co (II) in the mixed crystals has an unusual temperature dependence which correlates with the Néel temperature.
High Resolution Spectroscopy of the υ5 Band of Fluoroform-d (CDF3) by the Laser Stark Method
Authors: Ibisch E. , Andresen U.
Published: February 2015

The υ5 perpendicular band of CDF3 has been studied by means of laser Stark spectroscopy using the 10.4 μm band of the 12C 16O2 and the 12C 18O2 laser as infrared radiation sources. The assignment was established for more than 500 resonances. The majority of them was measured in saturation dip technique. A least-squares analysis of the Stark spectrum, together with recent microwave and infrared results, gave the rotation-vibration parameters and the dipole moment of the υ5 state. A brief description of the apparatus is also given.
Chlorine NQR on Derivatives of Chloral
Authors: Hashimoto Masao , Weiden Norbert , Weiss Alarich
Published: February 2015

The 35Cl-NQR spectrum of several derivatives of chloral, Cl3CCHO, was studied in the ranee 77 K ≦ T ≦ Tm. By use of the spin echo double resonance technique a relative assignment of the resonances to different Cl3C-groups within one crystallized compound was possible. The solid compounds studied are: High temperature phase of chloral hydrate, Cl3CCH(OH)2; parachloral, (Cl3CCHO)3, (α-and ß-isomer); the two phases of chloral hemihydrate Cl3CCHO · 1/2 H2O; chloralide (II); chloralhemithiohydrate, Cl3CCHO · 1/2 H2S. The structure of the molecules in the solid state and the fade out of the NQR resonances are discussed.
Schwingungsberechnungen des käfigstrukturierten P4S3
Authors: Cyvin S. J. , Brunvoll J. , Cyvin B. N. , Somer M. , Brockner W.
Published: February 2015

The P4S3 molecule is supposed to have a cage-structure of C3V symmetry. A normal coordinate analysis for this molecule was performed, based on a very simple initial force field with three numerical parameters and valence coordinates including redundancies. A complete set of independent symmetry coordinates is given. The force field was refined by adjusting the symmetry force constants to fit exactly a set of observed frequencies. This final force field was used to calculate the first-order Coriolis coupling coefficients and the mean amplitudes of vibrations. The standard thermodynamics functions from spectroscopic data are also given.
Calculation of Molecular Constants for the 1∑+ Ground States of the NeH+ and KrH+ Ions
Authors: Rosmus P. , Reinsch E.-A.
Published: February 2015

Potential energy and dipole moment functions have been calculated for the ground states of the NeH+ (1.0 ≦ R ≦ 15 a. u.) and the KrH+ (1.6 ≦ R ≦ 20 a. u.) ion from highly correlated SCEP/VAR and SCEP/CEPA electronic wave functions. The following spectroscopic constants have been derived: Ne20H+ re = 0.996 ± 0.003 Å, ωe = 2896 ± 20cm-1 , D0(Ne + H+) = 2.10 ± 0.05 eV; Kr84H+ re = 1.419 ± 0.003 Å, ωe = 2561 ±20 cm-1 , D0(Kr + H+) = 4.65 ±0.05 eV. The Einstein transition probability coefficients of spontaneous emission have been calculated for all transitions v ≦ 5 of Ne20H+, Ne20D+, Kr84H+ and Kr84D+, respectively.
Recombination Constants Calculation of Reactions between Fluorine Atoms and O2, CO, NO2, SO3, FSO3, ClO2, NF2, and CIF
Authors: Jubert A. H.
Published: February 2015

Recombination constants for reactions between fluorine atoms and O2, CO, NO2, SO3, FSO3, ClO2, NF2 and CIF were calculated by means of a method developed by J. Troe. N2 was used as bath gas and a temperature of 300 K was considered. The following values were obtained: 1.7 × 1016 , 9.2 × 1016 , 2.2 × 1017 , 7.0 × 1018 , 1.7 × 1019 , 2.6 × 1017 , 1.0 × 1017 , 2.3 × 1016 cm6 mol-2 s-1 respectively.
Die Lösungsmittelabhängigkeit der Elektronenspektren und die Änderung der Dipoleigenschaften N-substituierter Acridone bei elektronischer Anregung / The Solvent Dependence of the Electronic Spectra and the Change of the Dipole Properties of N-Substituted Acridones at Electronic Excitation
Authors: Siegmund M. , Bendig J.
Published: February 2015

The absorption and fluorescence spectra of acridone, N-methylacridone and N-phenylacridone are measured at 298 K for 35 solvents of different polarity. For the long wave 1La-transition, which shows a distinct positive solvatochromism, the oscillator strenght and the natural fluorescence lifetime are calculated. The change of the dipole moment (pd), determined from the Stokes’ shift as a function of solvent polarity, is nearly parallel to that of the ground state (pg). The absolute values and directions of pg and pe confirm the increasing polar character of the S1-state within the sequence N-phenylacridone, acridone and N-methylacridone. These values are used for an interpretation of the charge distribution and solvatation of the S0- and S1-states. By consideration of the solvent relaxation and the activation energy of the temperature dependent S1-T2 intersystem crossing process it is shown that in addition to the decrease of the S1-energy with increasing solvent polarity the T2-energy increases relative to S0, especially in the case of protic solvents.
Equivalence of the Variational Criteria in the Calculation of the Nuclear Spin-Spin Coupling Constant of HD
Authors: Trivedi H. P.
Published: February 2015

Using symmetry arguments it is shown that the variation of the self coupling, the cross coupling and the total second order energy are equivalent criteria for the calculation of the nuclear spin-spin coupling constant of HD and larger symmetric molecules. A previously given condition guaranteeing this equivalence is shown to be unnecessarily restrictive.
Quantum Statistical Derivation of Rate Equations for Electronic Processes in Polar Crystals with External Electric Field
Authors: Stumpf H. , Kleih W.
Published: February 2015

Applying the Nakajima-Zwanzig method to the von Neumann equation of a system of interacting electrons and nuclei, etc., and evaluating the Pauli-Master equation according to Rieckers-Stumpf, we obtain a system of reaction equations for electron-phonon-photon processes in a polar crystal. Further elaboration of these reaction equations leads to rate equations for electrons which include impurity center processes as well as conduction band processes in an external electric field. If the conduction band processes run faster than the other processes, the rate equations can be reduced to a Boltzmann equation with drift term for the conduction electrons, coupled to rate equations for impurity center electrons where the number of conduction electrons must not be conserved. Furthermore, the basic problem of electronic state formation in external fields is discussed, the corresponding interaction terms are derived and a functional for the calculation of "bound" states in external fields is given.
Structure Factors of Liquid Cu-Pb Alloys by Neutron Diffraction
Authors: Lamparter Peter , Steeb Siegfried
Published: February 2015

By means of neutron diffraction the structure factors and pair correlation functions of five Cu-Pb alloys, Cu, and Pb in the liquid state have been determined. The nearest neighbour distances have been obtained. The marked effect of small angle scattering with the melt with critical composition (65 at % Cu) is a proof for microsegregation tendency. By comparison with a segregation model for the structure factor the short range order parameter has been derived for melts with 65 and 35 at % Cu, respectively.
Local Instabilities of Quantum Trajectories in Non-Linear Dynamical Systems
Authors: Brickmann J.
Published: February 2015

Local instability of wave packets is related to an exponential increase of the second moments of the components ⊿Pi2 and ⊿Qi2 of the momentum and position operator as a function of the expectation values  and • Equations of motion for ⊿Pi2 and ⊿Qi2 are derived. In the quasiclassical limit, the instability criterion approaches the Toda-Brumer criterion [1, 2] for classical trajectories.
Viskositäts-und Lösungsmittelabhängigkeit der Fluoreszenzanisotropie und der Lebensdauer von p-Terphenyl
Authors: Kawski A. , Kojro Z. , Alicka M.
Published: February 2015

The fluorescence anisotropics (FA) r and the lifetimes of p-terphenyl in different solvents have been measured, the effective volumes and the rotational relaxation times being determined. The deviation from the linear dependence of 1/r on 1/η (η-viscosity of the solvent) may explained by the length of the p-terphenyl molecule. The FA measurements were carried out by a method with an Arago compensator, a new method of the automatization of measurements being employed.
Scattering on Magnetic Monopoles
Authors: Petry Herbert-Rainer
Published: February 2015

The time-dependent scattering theory of charged particles on magnetic monopoles is investigated within a mathematical frame-work, which duely pays attention to the fact that the wave-functions of the scattered particles are sections in a non-trivial complex line-bundle. It is found that Möller operators have to be defined in a way which takes into account the peculiar long-range behaviour of the monopole field. Formulas for the scattering matrix and the differential cross-section are derived, and, as a by-product, a momentum space picture for particles, which are described by sections in the underlying complex line-bundle, is presented.
EPR Study of Mn2+ in Hg(ClO4)2 · 6H2O Single Crystals
Authors: Jain Viraal Kuraar
Published: February 2015

The electron paramagnetic resonance of Mn2+ in Hg(ClO4)2 · 6H2O has been studied at X-band at 298 K and 77 K. Mn2+ is found to substitute Hg 2+ . The spectra have been analysed using the spin-Hamiltonian appropriate for trigonal symmetry. From the unequal separations between the Δm = ± 1 doublets in M = + 1/2 → - 1/2 transitions, the value of the axial part of the quadrupole coupling constant is determined. The observed doublet separations of forbidden hyperfine transitions in M = + 1/2 → - 1/2 are in good agreement with those cal-culated.
On Dielectronic Recombination in Some Coronal Ions
Authors: Mital H. P. , Narain U.
Published: February 2015

Dielectronic recombination rate coefficients for some ions found in the solar corona have been investigated in the temperature range 20-1000 eV using two different expressions. A comparison has also been made with the corresponding radiative recombination rate coefficients.
Formation of BrO2 in the Belousov-Zhabotinsky-System — Investigation of the HBrO2 /BrO3
–-Reaction
Authors: Försterling H. D. , Lamberz H. J. , Schreiber H.
Published: February 2015

The reaction between HBrO2 and bromate was studied in sulfuric acid solution. From the spectral dependence of the absorbance in the region from 400 to 600 nm it is concluded that BrO2 is an intermediate of the reaction. From the maximum concentration of BrO2 the equilibrium constant of the BrO2/Br2O4-equilibrium is evaluated; furthermore, a value for the ratio of the rate constants for the HBrO2/BrO3
--reaction and the disproportionation reaction of HBrO2 is given.
On the Thermal Behaviour of the n.C13 -n.C 20 Rubidium Soaps
Authors: Cingolani A. , Sanesi M. , Franzosini P.
Published: February 2015

The odd and even long-chain rubidium soaps from tridecanoate to eicosanoate were submitted to DSC analysis in the range between room temperature and the isotropic liquid region. The information thus obtained, together with that already collected for shorter homologues, made it possible, inter alia, to outline the boundaries of the mesomorphic liquid region in the whole C5-C20 series. Comparison is also made with the previously investigated thermal behaviour of potassium n.alkanoates.
On the Interaction of Insoluble Alkyl Alcohol Monolayers with Aqueous Solutions of Ionic Surfactants
Authors: Eicke H.-F. , Sharma M. K.
Published: February 2015

The interaction between so-called alkyl alcohol (C5-C8) monolayers and aqueous solutions of ionic surfactants with different hydrophilic properties, i.e. calcium di-2-ethylhexyl sulfosuccinate and sodium dodecyl sulfate, has been studied with the help of a Langmuir-Adam film balance. A decrease or increase in surface pressure of the alkyl alcohol monolayers with the addition of surfactants is observed. The shift of the critical concentration (cmc) to increasing surfactant concentration occurs at intermediate surface pressures. This is interpreted as due to the formation of mixed alcohol-surfactant aggregates. The maximum of the cmc as a function of the pressure can be explained by a thermodynamic treatment assuming competition between a pressure dependent solubility of alcohol molecules and the formation of mixed alcohol surfactant complexes. The amount of alkyl alcohol required to react with the surfactant has been evaluated at different surface pressures, which shows values similar to those known from cosurfactant studies in the bulk phase. Critical micelle concentrations of the surfactants were verified by conductivity measurements.
Notizen: Dispersion Energy Contribution to Solute-Solvent Interaction
Authors: Mahanty J. , Rao C. N. R.
Published: February 2015

Solubility of a non-polar solute in non-polar solvents is shown to depend on solvent refractive index.
Elastic Constants of Nematic Phenylpyrimidines Determined by Two Different Methods
Authors: Scharkowski A. , Schmiedel H. , Stannarius R. , Weißhuhn E.
Published: February 2015

A survey of various methods to measure the elastic constants Ki of nematic liquid crystals is given. To determine K1, K3 and the anisotropy of the diamagnetic susceptibility Δx of two members of the 5n-hexyl-2-[4n-alkyloxy-phenyl]-pyrimidines and a mixture of both, we used a combined electromagneto- optical method, consisting in independent measurements of the optical phase difference in electric and magnetic fields acting on the same cell. The temperature dependence of the K1- and K3-values for these phenylpyrimidines can be explained by common theories. The Δx data show the same temperature dependence as the values of the orientational order parameter S obtained by 1H-NMR.
Anomalous X-ray Scattering Study of the Quasi-crystalline Al65Cu20Fe15 Alloy
Authors: Matsubara E. , Waseda Y.
Published: February 2015

The environmental radial distribution functions (RDFs) around Cu and Fe as well as the ordinary RDF of an as-quenched Al65Cu20Fe15 alloy have been determined by anomalous x-ray scattering (AXS) and conventional x-ray diffraction techniques. The experimental information indicates that a strong directional dependence along the symmetrical axes exists for the Cu atoms but not for the Fe atoms. Almost identical RDFs were also obtained in both the as-quenched and fully-annealed states of the Al65Cu20Fe15 alloy. Thus, the small differences observed between diffraction profiles of the as-quenched and annealed samples of this alloy may be attributed to defects or strains introduced during the rapid quenching process.
What do We Know about the Numbers of Benzenoid Isomers?
Authors: Brunvoll J. , Cyvin S. J.
Published: February 2015

The numbers of benzenoid chemical isomers, represented by the formulas CnHs, are reviewed. The data which have been deduced from the available literature are supplemented.
Study of the Metastable Decay of Single Size Benzene Clusters by an Ion Stopping Technique
Authors: Sengteller S. , Selzle H. L. , Schlag E. W.
Published: February 2015

A method has been developed which allows to stop single sized cluster ions in a superionic jet. This cluster will stay isolated in space for a long time and photochemical processes can be studied without perturbation from the other clusters in the jet. This allows to uniquely identify the parent complex, and the metastable decay of this complex can be analyzed.
An Estimate of the R.M.S. Radius of the 1s-State Orbital of the Λ-Particle in Hypernuclei
Authors: Koutroulos C. G.
Published: February 2015

The r.m.s. radius of the 1 s-orbital of Λ-hypernuclei is calculated in the case of Woods-Saxon potentials by assuming that the Δsᵱ spacing (obtained by a relativistic treatment) can be approximated by ħωΛ.
Superposition-Model Analysis of NQR Data for NaAlCl4
Authors: Vassilikou-Dova A. B. , Lehmann G.
Published: February 2015

The quadrupole splitting patterns for 23Na and 27Al in NaAlCl4 can very satisfactorily be reproduced by the distortions of their first coordination spheres, as shown by application of the superposition model. The same exponent of 7 for the dependence on bond lengths was used as previously found for NMR data of 9Be, 23Na, 25Mg, 27Al and 29Si with oxygen as ligand. The intrinsic splitting parameters are in the same range, perhaps a little larger than for oxygen as ligand. Small deviations between observed and calculated splitting patterns just outside the limits of error of the crystal structure data may be due to influences of the lattice, especially in the case of 27Al, for which the distortions are fairly small
Characteristics of Photoelectrochemical Cells Based on n/n+-Si and p/n+-Si Photoanodes Modified by Metal Films
Authors: Wang S. , Li G. , Li H. , Getoff N.
Published: February 2015

Photoelectrochemical cells (PECs), composed of different epitaxial n-Si photoanodes coated with evaporated metal film of Ni, Pt, Ni/Pt and immersed in solution with redox couple Br2/Br- or Fe(NC)3
6Fe(CN)4
6
- were investigated. The open circuit photovoltage and short circuit curent density of these PECs under optimum conditions by illuminating with a bromine-tungsten lamp (65 mW/cm2), are 0.494 V and 45.8 mA/cm2, respectively. By using a p/n+ junction for the epitaxial silicon and the Schottky barrier effect formed at the silicon-metal interface, a much higher conversion efficiency of optical to electrical energy up to 12.3% could be achieved
Triple Resonance Experiments in Microwave Fourier Transform Spectroscopy
Authors: Vogelsanger B.
Published: February 2015

Two-dimensional (2 D) correlation techniques in microwave Fourier transform spectroscopy have been extended to study triple resonance phenomena. Dipole-forbidden double- and triple-quantum transitions have been observed with a five-pulse sequence. The introduction of a phase cycle acting as a triple-quantum filter has simplified the recorded spectra. Experimental results on trifluoromethylacetylene are given as an example
Improved Version of a Microwave Fourier Transform Spectrometer in the Frequency Band from 26 to 40 GHz
Authors: Keussen Ch. , Schwarz R. , Andresen U. , Dreizler H.
Published: February 2015

We report the design and performance of an improved version of a microwave Fourier transform spectrometer in the frequency region between 26 and 40 GHz for the investigation of rotational spectra. The performance is illustrated by rotational transitions of allene-d4 and isotopomers of carbonyl sulfide in natural abundance. The high sensitivity of the spectrometer allows the measurement of very weak lines in only a few minutes
1H - 17O Nuclear Quadrupole Double Resonance in DL-Proline
Authors: Seliger J. , Žagar V. , Blinc R. , Kadaba P. K. , Fiat D.
Published: February 2015

17O nuclear quadrupole resonance spectra have been measured in an 17O enriched polycristalline sample of DL-proline with the help of 1H - 17O nuclear quadrupole double resonance technique. The results show the presence of eight chemically inequivalent oxygen sites corresponding to four inequivalent proline molecules in the unit cell. The oxygen sites may be grouped into two sets of four sites. One set with the short proton-oxygen distances belongs to the C - O • • • H groups whereas the other with the long proton-oxygen distances to the C = O groups
Possible Participation of Lithium in Fleischmann-Pons Reaction is Testable
Authors: Frodl P. , Rössler O. E. , Hoffmann M. , Wah F.
Published: February 2015

If the amount of heat reported by Fleischmann and Pons to occur in their electrochemical "fusion" experiment is assumed to be produced entirely by the "clean" nuclear reaction 6Li + 2D → 2dHe (22.4 MeV), then the concentration of 6Li in the reaction fluid should during a period of 120 hours go down by a measurable amount, namely between 3.4 and 0.25 percent dependent on whether the natural isotopic mixture of (less likely) pure 6 Li was used in the experiment
Access to Primary Charge Separation Mechanism in Photosynthetic Reaction Centers: Anisotropic Excitation Spectra of Electric Field Modulated Fluorescence Yields
Authors: Eberl U.
Published: February 2015

Two-step sequential and unistep, superexchange primary electron transfer form primary radical pair states which differ in the direction and magnitude of their dipole moments as revealed in the X-ray structure analysis. The direction can be measured by the excitation anisotropy of electric field induced changes of the fluorescence yield. This method determines angles between the dipole of the primary radical pair and photoselected transition moments (in absorption and emission) of cofactors in the reaction centers. Transitions particularly favourable for discrimination between the two models of primary electron transfer are discussed.
Gaussian Approach to (1 + 1) Dimensional φ6 Solitons at Finite Temperature
Authors: Roychoudhury Rajkumar , Sengupta Manasi
Published: February 2015

Using the Gaussian effective potential approach, φ6 soliton solutions at finite temperature are studied for both the general case and the particular case λ2 = 2ξm2. A critical temperature is found at which soliton solutions cease to exist. The effective potential together with the mass-gap equation are studied in detail, and comparison with existing work on this subject is made
Internal Mobilities in Molten (Li, Pb(II))Cl as Remeasured by the Klemm Method
Authors: Haibara Teruo , Okada Isao
Published: February 2015

Internal cation mobility ratios in molten (Li, Pb(II))Cl at 650 °C have been remeasured by Klemm's column method. From these and available data on the densities and conductivities, the internal mobilities bLi and bPb have been calculated. It was found that at low LiCl content bu is surprisingly high, while at low PbCl2 content bPb is surprisingly low. The former trend agrees with that found by Klemm and Monse with the migrating boundary method and disagrees with that found by Behl and Egan with the EMF method. The latter trend agrees with that resulting from a neglected point given by Behl and Egan and disagrees with that tentatively reported by Klemm and Monse. The peculiar mobility behaviour of (Li, Pb(II))Cl is compared with that of similar Cd(II), Sr, and Ba systems
Temperatur- und Konzentrationsabhängigkeit der 115In-Knightshift im flüssigen In-Mn-System
Authors: Senel I. , Quitmann D.
Published: February 2015

NMR measurements of the 115In-Knightshift and the linewidth in liquid In-Mn are reported. They were carried out in an external magnetic field of about 4.0 T at concentrations 0, 3, and 6 at.% Mn at temperatures from 400 K to 1300 K. According to our experimental results there are no localized magnetic moments in the liquid In-Mn-system. The experimental results are discussed in the framework of theories on metallic alloys.
On the Effective Interaction of two Hydrogen Centres in Niobium
Authors: Frodl P. , Sommer F. T. , Hau K. , Wahl F.
Published: February 2015

We derive an effective interaction between hydrogen impurities in Niobium using a microscopic theory of hydrogen in metals. Our model consists of an infinite bcc-crystal with two hydrogen centres occupying tetrahedral interstitial sites, neighbouring on the first to the fourth coordination shell. The elastic interactions are assumed to obey the classical harmonic approximation. The electronic interactions due to both the coulomb potentials and the overlap of the impurity induced electron densities in the vicinity of the interstitials also play an important role. These latter interactions are treated as two-body interactions in a zeroth order approximation of the New Tamm-Dancoffmethod. A separation ansatz results in an effective interaction which depends on the distance between the interstitials and upon the spin states of their excess electrons. We propose some improvements on our model, and to test our calculations, we construct the grand partition function of an appropriate lattice gas model.
Kinetic Derivation of Gauss's Law and Its Thermodynamic Significance
Authors: Dunning-Davies J. , Lavenda B. H.
Published: February 2015

Gauss's error law for generalized jump processes in which the average value is also the most probable value is derived from the maximum likelihood path for the growth of a fluctuation. Evolution towards equilibrium and the spontaneous growth of a fluctuation from equilibrium are analyzed and compared in the continuous, diffusion limit.
Black-Hole versus Black-Body Thermodynamics
Authors: Lavenda B. H.
Published: February 2015

According to the second law of thermodynamics, thermal interactions of material bodies lead to an increase in entropy. Black-hole thermodynamics has unknowingly repudiated this law of Nature.
Notizen: On the Spectra of Turbulent Fluids at Large k
Authors: Tasso H.
Published: February 2015

The turbulence spectra of continuous fluids at large k are discussed. A basic difference in behaviour appears between conservative and dissipative systems. Only in the latter case can one eliminate higher order ultraviolet divergences.
Quantum Features of Microwave Propagation in a Rectangular Waveguide
Authors: Marinescu Nicolae , Nistor Rudolf
Published: February 2015

The formal analogy between the distribution of the electromagnetic field in waveguides and microwave cavities and quantum mechanical probability distributions is put into evidence. A waveguide of a cut-off frequency ωc acts on an electromagnetic wave as a quantum potential barrier Ug = hωc
. A non-habitual time independent Schrödinger equation, describing guided wave propagation, is established
Ideal Gas Approximation for an Ion Cloud in a Penning Trap
Authors: Kretzschmar Martin
Published: February 2015

Assuming a sufficiently low density of the trapped particles the methods of equilibrium statistical mechanics for non-interacting particles are used to find expectation values and distribution functions for the most interesting 1-particle observables. The results are applied in a perturbation calculation to estimate space charge effects at low particle densities
The influence of solvent on the UV-visible absorption and luminescence spectra of some highly fluorescent vitamin derivatives, the products of the reaction of N-methylated vitamin Bj with cytidine (I), adenosine (II) and 2-amino-4-methylpyridine (III) is studied. Spectroscopic manifestations of protonation of I and II are also investigated using a semiempirical INDO/S CI method. Singlet and triplet energy levels of the free ion and several protonated species are calculated, and transition energies and oscillator strengths are compared with the experimental spectra. Calculated charge densities on heteroatoms in the ground and excited singlet and triplet states are correlated with changes of the experimental pKa values with excitation. The results for I and II are compared with those for the trimethylated pyrichrominium ion (III) previously studied
Authors: Muralimohan Rao D. , Kalidas C.
Published: February 2015

The conductance of HCl and HBr in water-dimethylformamide (DMF) mixtures of 10-80 wt % DMF at 25 ºC has been measured and discussed, using the three parameter conductance equation suggested by Fuoss et al. in 1965. The ionic conductances and Waiden products of the H + , C - and Br- ions have been determined and explained. No appreciable ion-association of these acids in these media has been found
Monte Carlo Simulation of Muscarine in Water Solution
Authors: Margheritis Chiara
Published: February 2015

Monte Carlo simulations of muscarine water solution were carried out using ab-initio SCFLCAO- MO interaction potentials. The overall results indicate that in water solution the preferred conformation, on the basis of enthalpic considerations, should be the one having the dihedral angle H02-02-C4-H4, τ, equal to 180°. The molecule shows a first hydration shell with about 35 water molecules: of these only about 25 are constantly present, 18 are at a distance equal to lower than 2.5 A and only 5 have an interaction energy larger than -21 kJ/mole. The results do not support the hypothesis that the role of Ol in muscarinic activity is that of increasing hydrophylic bonds
Notizen: Some Remarks on the Concept of Molecular Topology
Authors: Zander M.
Published: February 2015

Some general aspects of the concept of molecular topology are delt with. The role of the separability of topological and non-topological factors that determine molecular properties, as well as the "holistic" behaviour of certain classes of compounds are discussed. A suggestion regarding a deeper understanding of the role of molecular topology is made