bluuebunny/crossref_metadata_2025_split huggingface dataset:
Erweiterung der Neuen Tamm-Dancoff-Methode auf Phasen- übergänge in Vielteilchensystemen / Extension of the New Tamm-Dancoff Method to Phase Transitions in Many-Body Systems
Authors: Friederich A. , Gerling W. , Bleuler K. 
Published: February 2015

Abstract
We extend the New Tamm-Dancoff method by introducing intermediate states. In this way we are able to treat with the Green's function method the effect of nearby levels in many-body systems. We formulate the η-and the ζ-function method with intermediate states. Aldready in first order, the ζ-function method yields a whole series of new approximations in addition to known theories such as the Hartree-Fock theory and the Hartree-Bogoliubov theory. As an example we study intensively "the Hartree-Fock theory with intermediate states". The ζ-function method which is based on the η-function method yields in first order in addition to RPA, quasi-particle RPA and other approximations "RPA with intermediate states". We apply the Hartree-Fock theory with intermediate states and RPA with intermediate states to the exactly solvable Lipkin model.
Mikrowellenspektrum, rotationsspektroskopische Konstanten und r0-Struktur des CSFCl / Microwave Spectrum, Spectroscopic Constants and r0 Structure of CSFCl
Authors: Kohrmann Hans Joachim , Zeil Werner 
Published: February 2015

Abstract
The microwave spectra of following isotopic species 12. 12C32S19F35Cl, 12C32S19F37Cl, 12C34S19F35Cl, 13C32S19F35Cl have been measured. The rotational constants and the centrifugal distortion constants have been determined and a r0 structure calculated.
The structure parameters are: rCS 1.595° Å, rCF 1.326° Å, rCCl 1.715° Å, ∢ SCF 123.82°, SCCl 127.12°.
The Interaction of a Large Amplitude Travelling Wave with a Cylindrical Plasma
Authors: Finken K. H. , Stampa A. , Tuczek H. 
Published: February 2015

Abstract
In connection with the problem of radio frequency heating of plasma, the interaction of a high power wave (0.1 GWatts) with a cylindrical plasma is investigated experimentally for frequencies near the ion cyclotron frequency and in the region between the ion cyclotron frequency and the lower hybrid frequency. It is found that a geometric resonance can be excited in which more than 90% of the wave energy is absorbed by the plasma. At frequencies around the ion cyclotron frequency, the macroscopic properties of the plasma, including distortion of the wave by large amplitude effects, can be fairly well explained by a MHD-model assuming an anomalous resistivity. The enlarged collision frequency is attributed to the presence of turbulence which is excited by drift currents connected with the wave.
On Drago's E-C Equation, Pearson's HSAB Rule and the Ionic Approximation to Chemical Bonding
Authors: Van Hooydonk G. 
Published: February 2015

Abstract
An attempt is made to explain the E-C formalism for ionic interactions in terms of the ionic approximation to chemical bonding. Dravo's E-C equation is seen to be a first approximation to the bond energy equation as it is given by the ionic bonding approach. The meaning of the ratio C/E is discussed and its relation with the hardness and softness of interacting species, as these occur in Pearson's HSAB rule, shows that the electron affinity or electronegativity of elements completely determines the chemical behaviour of ionic species. This analysis illustrates the consistency of the ionic approximation to chemical bonding.
The Elastic Constants of a Nematic Liquid Crystal
Authors: Gruler Hans 
Published: February 2015

Abstract
The elastic constants of a nematic liquid and of a solid crystal were derived by comparing the Gibbs free energy with the elastic energy. The expressions for the elastic constants of the nematic and the solid crystal are isomorphic: k ∝ ∣ D ∣ /1. In the nematic phase ∣ D ∣ and I are the mean field energy and the molecular length. In the solid crystal, ∣ D ∣ and l correspond to the curvature of the potential and to the lattice constant, respectively. The measured nematic elastic constants show the predicted l dependence.
Röntgen-Beugungsuntersuchungen an geschmolzenem Tellur / X-ray Diffraction Study of Molten Tellurium
Authors: Hoyer W. , Thomas E. , Wobst M. 
Published: February 2015

Abstract
X-ray Diffraction Study of Molten Tellurium An X-ray diffraction apparatus with focusing geometry used for the investigation of free surfaces of melts and a computer programme for the analysis of scattering intensities are discribed. The results of our measurements on molten tellurium at 480, 550 and 620 °C are presented and compared with a model of the temperature change of the short range order in molten tellurium as described by Cabane, Tourand and Breuil 14-17.
The important result is that the number of nearest neighbours is approximately 3 at all the 3 temperatures. This suggests that the short range order is changing at the melting point from a chain structure to an antimony-like structure.
The Structure of Liquid Silver-Copper Alloys
Authors: Lukens W. E. , Wagner C. N. J. 
Published: February 2015

Abstract
Mo-Kα X-rays have been used as a radiation probe to evaluate the interference functions l(K) (also called structure factors) of liquid Ag, Cu and Ag-Cu alloys with 16.5, 28, 37, 50, 57, 71 and 85 at.% Cu at temperatures about 50 °C above the liquidus. Employing the transmission technique, I(K) has been determined in the range of K = 4 π sin θ/λ between 0.8 and 12.5 Å-1. The partial interference functions Iij(K) have been calculated, and it was found that the assumption of concentration independence of Iij(K) yielded reduced partial distribution functions Gij(r), the weighted sum of which were in excellent agreement with G(r), the Fourier transform of F(K) =K[l(K)-1]. The position of the first peak in G(r) and the coordination number η show a positive deviation from a straight line when plotted as a function of concentration.
Infinite Matrices, Ritz Theorem and Bound State Problems
Authors: Mitra A. K. 
Published: February 2015

Abstract
The straight forward application of the Ritz variational technique has been shown to be a very convenient method for obtaining numerically the first few discrete eigenvalues of the Schroedinger operator with certain special types of potentials. This method solves essentially the (finite) matrix eigenvalue problem obtained by truncating the infinite matrix representing the Schroedinger operator with respect to the Coulomb wave functions. The Ritz theorem justifies the validity of this truncation procedure.
E-Typ-verzögerte Fluoreszenz von Circobiphenyl in einer Kunststoffmatrix / E-type delayed fluorescence of circobiphenyl in a plastic matrix
Authors: Zander M. 
Published: February 2015

Abstract
In 1. c. 1 war gezeigt worden, daß Circobiphenyl (I) die aufgrund seines relativ kleinen S1-T1-Inter-valls von ca. 4kK zu erwartende E-Typ-verzögerte Fluoreszenz zeigt.
Energy Transfer and Superradiance Between Two High Temperature Carbon or Nitrogen Plasmas
Authors: Norton B. A. 
Published: February 2015

Abstract
Efficient superradiant wavelength conversion and focus-sing in the vacuum UV region below 300 Å is described for Carbon and Nitrogen plasmas. In this scheme a plasma containing predominantly Helium-like ions is pumped with optically thick resonance radiation from Hydrogen-like ions in a neighbouring plasma of higher temperature. Such a two-plasma system could exist in the earth's atmosphere, or in the laboratory by irradiating a suitable target with a high-powered laser. The power requirements in the latter case are within present capabilities.
Angular Momentum and Discrete Symmetries in the Spinor Bethe-Salpeter Equation
Authors: Bauhoff W. 
Published: February 2015

Abstract
The group-theoretical basis for the angular momentum reduction of the spinor Bethe-Salpeter equation is discussed. We construct amplitude of definite angular momentum by analogy to the nonrelativistic problem and discuss the differences. The additional decomposition because of discrete symmetries is explained. Finally, we relate the states to those obtained in the non-relativistic quark model.
Frequency Dependence of Proton Spin Relaxation in Liquid Crystalline PAA
Authors: Wölfel W. , Noack F. , Stohrer M. 
Published: February 2015

Abstract
We report on measurements of the Larmor frequency dependence of the proton spin relaxation time T1 in the nematic and isotropic phase of p-azoxyanisole (frequency range: 3.8 kHz ≦ ωL/2 π≦75 MHz) . In both cases our results clearly support the Pincus-Cahane mechanism of spin relaxation by order fluctuations ("ωL−½-law") and exclude the alternative translational dif­fusion model (“ωL+½-law”). For the isotropic phase it was possible to evaluate the correlation time τ of the liquid crystalline order fluctuations from the observed T1 dispersion. As a function of the deviation ⊿ν=ν-νc from the critical nematic-isotropic transition temperature, νc= (136± 0.5)°C, we found τ=2.71·10-7-⊿ν-0.25s .
Thermal Instability in Plasma with Finite Larmor Radius
Authors: Sharma R. C. , Prakash Kirti 
Published: February 2015

Abstract
The effects of the finite Larmor radius of the ions on the thermal instability of a plasma are investigated. When the instability sets in as stationary convection, the finite Larmor radius is found to have a stabilizing effect. The conditions for the nonexistence of overstability are investigated. The case with horizontal magnetic field is discussed.
Zur Ladungstrennung bei der sensibilisierten Löcherinjektion in Anthracenkristallen / Charge Separation and Sensitized Hole Injection into Anthracene Crystals
Authors: Michel-Beyerle M. E. , Bube W. , Haberkorn R. 
Published: February 2015

Abstract
The dependence of the sensitized injection current and of the crystal's sensitized delayed fluorescence on the electric and magnetic field is utilized to examine the process of charge separa-tion at the phase boundary crystal/water electrode. Hole currents, sensitized by electron transfer interaction between rhodamine B molecules in their lowest excited singlet state and the anthracene crystal, can be shown to originate from a thermal injection process. This conclusion is further supported by the changed phenomenology of the injection current and the delayed fluorescence in the presence of molecular oxygen in the aqueous electrode. In this case an alternative injection reaction predominates due to the oxygen enhancement of the intersystem crossing rate and thus of the sensitized population of triplet excitons in the crystal, the latter ones injecting holes through electron transfer to oxygen present at the surface.
Neglecting image-and Coulomb forces at the interface crystal/electrolyte, an analytical ex-pression for the current-voltage relation can be given which includes the influence of the space charge. This expression does well agree with the experimental current-voltage characteristics ob-served for different surface recombination rates of charge carriers.
The Conductance of Sodium Perchlorate in Water-sulfolane Mixtures at 35 °C
Authors: Petrella Giuseppe , Castagnolo Maurizio , Sacco Antonio 
Published: February 2015

Abstract
Measurements on the conductance of dilute solutions of sodium Perchlorate, at 35 °C, in water-sulfolane mixtures over the entire solvent composition range are reported. Experimental data were analyzed by the 1965 Fuoss-Onsager-Skinner equations.
No detectable ion association was found for this electrolyte, unlike sodium chloride in the same solvent mixtures. The association order KA(Cl-)>KA(ClO4
-) is in contrast with that observed in protic solvents [KA(ClO4
-)>KA(Cl-)] and is similar to that found in aprotic solvents. This shows that in water-sulfolane mixtures, association phenomena are mainly controlled by sulfolane.
The lack of transport numbers for water-sulfolane mixtures precludes unambiguous explanations for Waiden products A0η.
Focusing of an Intense Relativistic Electron Beam by a Hollow Conical Laser Beam
Authors: Winterberg F. 
Published: February 2015

Abstract
Estimates suggest that the nonlinear transverse radiation pressure produced within a plasma by a convergent annular high power laser beam may lead to the focusing of an intense relativistic electron down to a radius of ~10-4 cm. The transverse radiation pressure results from the dielectric property of a plasma in conjunction with the phenomena of the self-focusing of intense laser light. The tightly focused electron beams would make possible the release of thermonuclear energy by micro-explosions.
Herkunft der kleinen Maxima bei geschmolzenem Au, Ag und bei festem amorphem Ga / Origin of the Small Maxima inAu, Ag, and Ga
Authors: Richter H. , Breitling G. 
Published: February 2015

Abstract
Between the first and second maxima of the atomic distribution curves of molten Au, Ag, and solid liquid-like amorphous Ga a small, but sharp maximum at [r1′] Au, Ag · √2 3.84 Å and [r1] Ga · √3 4.83 Å occurs. Hence [ri′] Au,Ag = 2.72 Å and [ri]Ga = 2.79 Å follows as the shortest atomic distances of structure II and of the spherical close packing (structure I), respectively.
According to the structural model of Richter and Breitling in molten Au and Ag the shortest oblique distance of the square chain I of structure II shows up by the [ri′] Au,Ag· √2-distance. On the other side in solid amorphous Ga the shortest oblique distance of the rhombohedron chain II of structure I appears at the [ri]Ga· √3-distance. In both cases the respective maximum must be very small because of the large variations in distance of the shortest oblique distances.
Investigation of the Structure of the v5 Band of Monofluoroacetylene
Authors: Huhanantti Mikko , Kauppinen Jyrki 
Published: February 2015

Abstract
The rotational structure of the bending fundamental v5 of monofluoroacetylene around 366 cm -1 was investigated. The measurements were performed using a Michelson type Fourier spectrometer with a resolution of about 0.05 cm -1 . The values B0=0.32373 cm -1 , a5
-= - 6.00 x 10 -4 cm -1 , q5= 6.3 x 10 -4 cm -1 and D = 11.2 x 10 -8 cm -1 were obtained from the analyses of the P-, Q-, and R-branches. In addition, some hot bands accompanying the fundamental were studied.
Transporteigenschaften und Quantenoszillationen von Te-und Sn-dotiertem Bi94Sb6 / Transport Properties and Quantum Oscillations of Te- and Sn-Doped Bi94Sb6
Authors: Schneider G. , Trommer R. 
Published: February 2015

Abstract
Electronic transport properties of undoped, Te- and Sn-doped Bi-Sb-alloys of approximate composition Bi94Sb6 were measured within the temperature range 10-300 K. Besides the electrical conductivity and thermoelectric power the magnetoresistance, the Hall effect and the thermoelectric power in a magnetic field were investigated. Measurements in low magnetic fields yield the mobility tensor for Te-doped samples and in connection with the Shubnikov-de Haas oscillations in higher magnetic fields the effective mass tensor of the electrons. Corresponding investigations on Sn-doped p-conducting samples in this paper give the mobility tensors of light and heavy holes and approximately the effective mass tensor. Here quantum oscillations of the thermoelectric power in a magnetic field were analysed.
Notizen: Energy of the Quasi-free Electron State in Liquid Argon, Krypton, and Xenon
Authors: Tauchert W. , Schmidt Werner F. 
Published: February 2015

Abstract
The energy of the conduction state in liquid argon, krypton, and xenon was measured by means of the photo-effect. The data are used to calculate the scattering lengths. The relation between scattering length and electron mobility is discussed.
On the Fluorescence Quenching of Polycyclic Aromatic Hydrocarbons by Nitromethane
Authors: Dreeskamp H. , Koch E. , Zander M. 
Published: February 2015

Abstract
Fluorescence quenching of 22 polycyclic aromatic hydrocarbons by nitromethane in toluene and acetonitrile solutions has been studied. Contrary to Sawicki’s observations that the fluorescence of hydrocarbons with the fluoranthene skeleton is not quenched that of 11.12-and 3.4-benzofluor-anthene and fluoranthene itself is quenched. These compounds have a high energy of the fluorescence transition. The fluorescence quenching of the compounds investigated follows a dynamic quenching mechanism. The bimolecular rate constant of fluorescence quenching increases exponentially with the energy of the fluorescing state of alternant hydrocarbons.
Notizen:Kernmagnetische Relaxationszeit-Messungen an OH-Protonen einer kristallinen Kieselsäure/ Nuclear Magnetic Relaxation Measurements on the OH-Protons of a Crystalline Silicic Acid
Authors: Wittich E. K.-H. , Voitländer J. , Lagaly G. 
Published: February 2015

Abstract
The transversal relaxation times of the OH-protons of a crystalline silicic acid were measured. Two relaxation processes, clearly separated from each other, are related to the OH-protons in the silicate layers and to the OH-protons of water molecules in the interlayer spaces. From the initial magnetizations information is obtained about the water content in the interlayer space which does well agree with results given in thermal decomposition curves.
Density-Functional Formalism
Authors: Szasz L. , Berrios-Pagan I. , McGinn G. 
Published: February 2015

Abstract
A new Density-Functional (DF) formula is constructed for atoms. The kinetic energy of the electrons is divided into two parts: the kinetic self-energy and the orthogonalization energy where these concepts are borrowed from the pseudopotential theory. For the radial part of the ortho-gonalization energy which replaces the radial part of the Fermi-energy of the Thomas-Fermi model we derived the expression

where p is the momentum, the ak's are constants and pε is the momentum width associated with the self-energy for which an expression is derived. Calculations were made for the total energies of neutral atoms, positive ions and for the He isoelectronic series. For neutral atoms the results match the Hartree-Fock energies within 1 % for atoms with N < 36; for atoms with N > 36 the results generally match the HF energes within 0.1%. For positive ions the results are fair; for the He series we achieved four or five-digit agreement between our energies and the HF results. For molecular applications a simplified model is developed in which the kinetic energy consist of the Weizsäcker term plus the Fermi energy reduced by a continuous function η(N). It is shown that the η(N) can be constructed in such a way that the energies computed closely approximate the HF energies for all neutral atoms.
Electron-Electron Bremsstrahlung in a Hot Plasma
Authors: Haug E. 
Published: February 2015

Abstract
Using the differential cross section for electron-electron (e-e) bremsstrahlung exact to lowest-order perturbation theory the bremsstrahlung spectra and the total rate of energy loss of a hot electron gas are calculated. The results are compared to the nonrelativistic and extreme-relativistic approximations available and to previous work. The e-e contribution to the bremsstrahlung emis-sion of a hydrogenic plasma is found to be not negligible at temperatures above ≈ 108 K, especially in the short-wavelength part of the spectrum.
CNDO-CI-Berechnungen zum Einfluß der N-Acylierung auf das Absorptions-und Phosphoreszenzspektrum von Carbazol/ CNDO-CI Calculations of the Effect of N-Acylation on the Absorption and Phosphorescence Spectra of Carbazole
Authors: Zander Maximilian , Fratev Filip , Olbrich Gottfried , Polansky Oskar E. 
Published: February 2015

Abstract
The observed blue shift of the carbazole chromophore by N-acylation has been verified by CNDO-CI-calculations of fluorene, carbazole and N-formyl-carbazole. From the CNDO-CI results which are in excellent agreement with the experimental data, a detailed analysis of the spectra is derived.
Double Resonance Modulation as a Standard Technique in Microwave Spectroscopy I. Principles and Operation
Authors: Stiefvater Otto L. 
Published: February 2015

Abstract
A versatile spectrometer with facilities for modulation by the microwave-microwave double resonance effect has been constructed for the continued evaluation of the double resonance modulation (DRM) technique. Investigation of the DR signal pattern and intensity for different modes of operation indicates that optimum results are achieved with a large frequency modulation of the pump radiation, and with one pump frequency precisely on resonance. The high sensitivity of the DRM spectrometer to the effects of not exactly resonant pump radiation leads to the occurrence of multiple double resonances (DRs) and makes double resonance double search experiments practicality feasible. The double resonance map is introduced as a convenient means for the presentation of DR-spectra, and miscellaneous practical aspects are reported.
Notizen: Magnetische Wechselwirkung der Elektronen/ Magnetic Interaction of Electrons
Authors: Heitzmann Martha 
Published: February 2015

Abstract
Magnetic Interaction of Electrons Electrons have, besides their charges, spins with magnetic dipolmoments. Therefore there are also magnetic forces, attractive or repulsive, between these particles at low distances. According to the position of the moments there is a distance in which the magnetic attraction has the same absolute value as the electric repulsion and will be larger at lower distances. This is discussed in the context of the formation of atoms, negative ions and molecules.
Notizen: Abschätzung der Lebensdauer des 317,9 keV- Zustandes in 129Xe/ Lifetime Estimation of the 317.9 keV-Level in 129Xe
Authors: Engel H. , Gerst E. , Schneider H. , Spitz R. 
Published: February 2015

Abstract
The 93.5 keV-317.9 keV-cascade was used in a delayed γ-γ-coincidence experiment to measure the lifetime of the 317.9 keV-level in 129Xe. The excited states of 129Xe were populated by the decay of 129Cs. A combination of a NaI (Tl) -and a Ge (Li) -detector was used. The evaluation of data resulted in the following estimation
T½(317.9 keV-level, 129Xe) < 500 ps.
Irreversible Thermodynamics of Nonequilibrium Alignment Phenomena in Molecular Liquids and in Liquid Crystals
Authors: Hess Siegfried 
Published: February 2015

Abstract
To treat nonequilibrium alignment phenomena in molecular liquids and in liquids crystals two points of the usual irreversible thermodynamics have to be modified. Firstly, in the specific energy a term quadratic in the alignment tensor is included. Secondly, terms up to 4th order in the alignment are taken into account in the entropy for a nonequilibrium situation. Then the entropy production is calculated. Constitutive laws are set up for the friction pressure tensor and for the tensor which characterizes the decay and the production of the alignment in the balance equation for the alignment tensor. As a first application, the nonlinear relaxation equation for the alignment is considered. For a uni-axial alignment zero and nonzero stable stationary values of the order parameter are found for temperatures above and below the temperature TK at which the transition from the isotropic to the nematic phase takes place. Small deviations from the equilibrium alignment decay exponentially. For temperatures below TK the relaxation time turns out to be anisotropic. In the appendix, the entropy associated with the alignment is calculated for a special case.
Calculations and Measurements of the Dynamic Stark Effect in Hydrogen
Authors: Rutgers W. R. , Kalfsbeek H. W. 
Published: February 2015

Abstract
A theory is given for the spectral profile of the first hydrogen Balmer line when the radiating neutral atom is under influence of both (quasi-) static and harmonically oscillating electric fields. Profiles, measured in a turbulent heating experiment, show a series of intensity maxima on the wings of the Balmer lines. If we assume a model for the spatial distribution of turbulent wave vectors, we can derive the fieldstrength and the direction of low-frequency (ion-acoustic) oscillations and the strength and frequency of high-frequency (Langmuir) oscillations.