bluuebunny/crossref_metadata_2025 huggingface dataset:
Impulsspektroskopische Untersuchungen der Elektronenspinrelaxation in freien Radikalen
Authors: Brändle R. , Krüger G.J. , Müller-Warmuth W.
Published: February 2015

Direct measurements of the electronic relaxation times T1 and T2 have been carried out in crystalline free radicals, in radicals diluted in solids, and in liquid solutions of free radicals. For this purpose, a pulse spectrometer operating at 9.3 GHz has been constructed, which is able to deliver 90° pulses of 20 ns duration, and to determine relaxation times of 3·10-8 s and longer. T1- and T2-measurements on DPPH (Diphenylpicrylhydrazyl) and BPA (Bis-diphenylenephenylallyl) have shown that the relaxation is governed by interactions between the Zeeman system and the exchange system of the electron spins down to the lowest temperature at which the ESR lines exist. The data are interpreted in terms of a simple model which takes into account exchange interaction between nearest neighbours of a linear chain of molecules. Furthermore, the electronic relaxation of organic crystals doped with free radicals has been investigated. - Finally, the relaxation of several free radicals has been studied in solutions of various organic liquids and of ammonia. From the temperature and concentration dependence it has been concluded that T1 can be explained by dipolar interactions between the electrons the time dependence of which is due to translational motion of the molecules. In contrast to nuclear relaxation data in liquids, the electronic T1 provides information for large ω τ-values, thus making possible a complete test of the theory of translational diffusion in liquids.
Effect of Inelastic Collisions on the Tail of the Electron Velocity Distribution
Authors: Oxenius J.
Published: February 2015

The effect of inelastic electron collisions with two-level atoms, having either two bound levels or one bound level and a continuum, on the electron velocity distribution is reconsidered. Attention is paid to the role played by physical parameters like cross sections, atomic occupation numbers, and temperature. Distribution functions and collision rates are given in terms of easily accessible tabulated functions.
Verbesserungen bei der Berechnung von Donatorniveaus durch Einführung einer effektiven Störstellenladung
Authors: Haug Albert
Published: February 2015

Die Berechnung von Donatorniveaus mittels des Modells der wasserstoffartigen Störstelle läßt sich erheblich verbessern, wenn man die Donatoren nicht als einwertige Ionen auffaßt, sondern ihnen eine geeignete effektive Ladung zuschreibt, die man aus den Verhältnissen bei freien Atomen ableiten kann.
Correlation Function Approach to Short-Range Order in the Ising-Model
Authors: Jelitto Rainer J.
Published: February 2015

By pushing forward the decoupling from the three-to the four-point correlation function short-range order is systematically introduced into the description of the statistical behaviour of the Ising-model. Application of a procedure which is a natural generalization of that invented by Bogoljubov and Tjablikov for the Heisenberg-model, leads to an overall-approximation for the magnetization and the nearest-neighbour correlation which may be compared with the Ising-model variant of Oguchi's two-spin-cluster molecular field theory. The results of both approximations are very similar both for low and high temperatures, but for the transition point the new approach yields values which lie considerably lower and therefore are more reliable than those following from Oguchi's theory. Moreover, the comparison with a slight modification of the theory which is also presented in this paper, illuminates the physical mechanism which is responsible for the formation of correlations within the order of approximation, considered.
Stark-Effekt-Untersuchung der Hyperfeinstruktur des 3 2P3/2-Zustands von Natrium mit der Level-crossing-Methode / Stark-Effect Investigation of the Hyperfine Structure of the 3 2P3/2-State of Sodium by Level-Crossing-Method
Authors: Zimmermann D.
Published: February 2015

The level-crossing-method has been used for an investigation of the hyperfine structure of the first excited 3 2P3/2-state of sodium applying an additional electric field parallel to the usual mag. netic field. By means of a detailed analysis of the measured change in intensity of the scattered fluorescence light due to the electric field the constant β of the quadratic Stark-effect of the 3 2P3/2-state of sodium was deduced to be β= (10.8± 1.2) kc/s·(kV/cm)2. The experimental result will be discussed with respect to a determination of upper and lower limits for oscillator strengths of transitions between the 3 2P3/2-state and S-states in the sodium spectrum.
Vibrational Potential Energy Distributions and Coriolis Coefficients for Extremal Force Constants in Bent XY2, Pyramidal XY3, and Tetrahedral XY4 Molecules
Authors: Freeman D.E.
Published: February 2015

For 27 molecules with approximately extremal force fields, an empirical distinction between hydrides and non-hydrides is linked, via the comparison of calculated and observed Coriolis coefficients, to a difference, based ultimately on the relative lightness of the hydrogen atom, in the potential energy distributions of hydrides and non-hydrides. The potential energy criteria of Becher and Ballein are compared to those corresponding to extremal diagonal force constants. Coriolis coefficients for the model of progressive rigidity are mostly in rough agreement with those observed.
Self-diffusion of Silver Ions in the Cubic High Temperature Modification of Silver Iodide
Authors: Kvist Arnold , Tärneberg Roy
Published: February 2015

The self-diffusion coefficient (D) of silver ions in silver iodide has been measured between 200 °C and 500 °C. The results can be described by the Arrhenius equation

D = 16.62 x 10-5 exp (-2190/RT),

where R is the gas constant in cal/mode, °K and T the temperature in °K. The standard deviation was 0.12 cm2/s.

The results coincide with Tubandt et al.1, whto investigated a small temperature interval around 200 °C.
Kritische Betrachtungen zu Ladungsverteilungen in Molekülen, erhalten durch SCF-MO-LCAO- Rechnungen
Authors: Janoschek R.
Published: February 2015

The numerical accuracy of population analysis as a tool for discussing the electron charge distribution in molecules is discussed. Theoretical bounds for the gross atomic charges resulting from the SCF-MO-LCAO method are derived. Calculated gross atomic charges which do not conform to these bounds are therefore inexact.
X-Ray Studies in the System Ti-Hg-Zn
Authors: Pušelj M. , Ban Z.
Published: February 2015

In a recent paper reported on part of the system Ti-Cu-Hg 1 a new phase TiCuHg2 was found having the crystal structure B 32 (NaTl type). The most inter-esting but hitherto unexplained feature of this structure is the degree of filling of the unit cell (71%). In order to examine which one of the metals in the structure is eventually responsible for the formation of this parti-cular phase, to which often a certain degree of ionic bonding is ascribed 2 , we tried to prepare the iso-structural compound TiZnHg2 . However, it turned out that its crystal structure belongs to the AuCu3 (Ll2) type (a = 4.02 ± 0.02 Ä), where all atoms are distri-buted statistically. We assume that the alternative con-figurations of the electron shells in the copper atom (3d 10 4s 1 or 3d 9 4s 2) may be responsible for such a behaviour. Diffractometer data for this phase are given in Table I. HKL d0 dc h h
Zur Erkennung schwacher Ranian-Banden durch digitale Spektrenauswertung: Isotopenaufspaltung der ν1-Frequenz des Kohlenstofftetrachlorids / Isolation of weak Raman-bands by digital computation The isotopic splitting of the ν1-frequency of Carbontetrachloride
Authors: Eysel Hans Hermann , Lucas Kai
Published: February 2015

The enhancement of the signal to noise ratio by error computation is demosntrated with the ν1-frequency of C 37Cl4 in carbontetrachloride.
Diagonalisierung des Hamilton-Operators in der feldtheoretischen Formulierung der nichtrelativistischen Mehrkanalstreutheorie
Authors: Walter R.
Published: February 2015

We discuss the general procedure of diagonalizing a field-theoretical Hamiltonian in the special case of a multi-channel scattering problem in which the asymptotic fields and the interpolating field are connected by a non-unitary transformation
On the Nonspherical Scattering Amplitude for Inelastic Molecular Collisions
Authors: Köhler W. E. , Hess S. , Waldmann L.
Published: February 2015

The rotational angular momentum dependence of the nonspherical scattering amplitude is investigated for inelastic collisions of linear molecules. As far as the approximation of small nonsphericity can be applied, this dependence is obtained from the angular momentum dependence of the nonspherical interaction potential. The connection between the nonspherical scattering amplitude and observables that can be measured by molecular scattering experiments involving a polarized beam is discussed. Some qualitative remarks are made on collision brackets occurring in the theoretical expressions for the bulk viscosity and for the Senftleben-Beenakker effect for H2 and HD
Bestimmung der Diffusionskonstante von Leitungselektronen in Anthracen aus dem Impulsabfall bei Driftexperimenten
Authors: Karl N. , Schmid E. , Seeger M.
Published: February 2015

Drift-current-pulses in semiconductors with vanishing dark conductivity measured according to the method of Kepler and LeBlanc deviate from the expected rectangular pulse shape even under ideal experimental conditions. In this work it will be shown that among other processes the diffusion of current carriers is responsible for the deviation. Under appropriate experimental conditions one is able to measure diffusion-constants in anthracene by a method to be described. Within experimental error the diffusion-constant obtained agrees with the value calculated from the Einsteinrelation using the independently measured drift-mobility. The differences in method from the known techniques used with dark conducting semiconductors are discussed. The measurements succeed only with very good crystals for which quality criteria are given
Die Molekeldichte und der Kondensationsgrad in kondensierten H2-Molekularstrahlen, die bei überkritischen Drücken erzeugt werden
Authors: Klingelhöfer R. , Röhl H.
Published: February 2015

The flux density and the velocity of hydrogen cluster beams are measured with nozzle temperatures between 34° and 39 °K and with inlet pressures between 15 and 35 atm. At a distance of about 20 cm from the nozzle exit number densities as high as 1 x 1018 H2-molecules/cm3 are found within a background density of about 5 x 1010 molecules/cm3. The degree of condensation is calculated from the measured kinetic energy of the beam particles and the known enthalpy of the gas before the expansion assuming that the final thermal energy of the expanded material can be neglected. Within the cited intervals of temperature and pressure degrees of condensation between 8 and 29% were found
Untersuchung der Temperatur und der Expansion von Funkenkanälen in H2 bei variabler Energiezufuhr
Authors: Martinen H. , Tholl H.
Published: February 2015

Measurements were carried out in order to investigate the temporal behaviour of temperatures in the channel axis of sparks in hydrogen in which different amounts of energy were released. It was found that with increasing energy input the temperature rises to approximately 60 000 °K . A further enhancement of temperature above this value could not be observed in spite of increasing energy dissipation. This effect can be explained by the fact that an increasing amount of the released energy is converted into expansion energy.

The temporal development of the channel radii was measured and was compared with calculated values using Drabkina's and Braginskii's theories. Good agreement between measured and calculated radii was found
Über die Elektronenspektren von N-(β-Naphthyl)-carbazol
Authors: Zander M.
Published: February 2015

In Fortführung unserer Arbeiten über die Elektronenspektren von N-Aryl-carbazolen 1, 2 haben wir das N- (β-Naphthyl) -carbazol (Strukturformel siehe Tab. 1) untersucht. Die bislang in der Literatur nicht beschriebene Verbindung wurde aus Carbazol und 2-Jod-naphthalin mit einem Verfahren, das sich bei der Herstellung anderer N-Aryl-carbazole bewährt hat3, dargestellt
An Estimate of Mean Diamagnetic Properties
Authors: Ludwig B. M. , Voitländer J.
Published: February 2015

Approximate closed expressions for the mean values of nuclear shielding constants and the diamagnetic susceptibility of 1Σ molecules are given which apply if a density matrix constructed over a set of pure Gaussian functions, is known
Numerische Berechnung der gekoppelten Verteilungen von Potential und Temperatur für Wasserstoff-Lichtbögen endlicher Länge in axialen Magnetfeldern
Authors: Raeder J. , Wirtz S.
Published: February 2015

The energy balance is used to derive a partial differential eqution for the heat flux potential in a rotational symmetric arc column of finite length. This equation is combined with a corresponding equation for the electric potential in order to calculate the distributions of temperature and electric potential for an arc discharge in a strong axial magnetic field. Because the coupling of the two equations is very complicated, all investigations have to be made numerically. The influence of mass flow is studied by taking into account drastically simplified distributions of the azimuthal and radial flow velocities.
Experimental Investigation of Plasma Production by Irradiating Solid Hydrogen Foils with an Intense Pulse Laser
Authors: Sigel R.
Published: February 2015

Foils of solid hydrogen were irradiated with a giant pulse ruby laser. The formation and ex-pansion of the plasma produced this way was investigated by time-resolved absorption measure-ments, by streak and framing photography, by holographic interferometry and by time-off-flight and charge collection measurements. The measurements yield a fairly complete picture of this process: After the initial breakdown in the solid a plasma is produced at the surface of the foil facing the laser. Owing to the high pressure of the plasma the solid hydrogen is compressed by a shock wave. This allows the layer in which the plasma is produced to penetrate into the interior of the foil with a velocity of 3 × 106 cm/sec. Thus under the action of the focused beam foils up to 1 mm thickness are pierced by the light before the end of the pulse. The plasma cloud, ejected towards the laser, contains 4 × 1016 ions with a mean kinetic energy of 200 eV this corresponding to about half of the absorbed energy. The observations are compared with the well known results obtained in a plane, one-dimensional geometry. If allowance is made for the influence of the focusing of the laser beam on the structure of the shock front, the observations are readily understood.
Functional Quantum Theory of Free Relativistic Fermi Fields
Authors: Stumpf H.
Published: February 2015

Functional quantum theory of free Fermi fields is treated for the special case of a free Dirac field. All other cases run on the same pattern. Starting with the Schwinger functionals of the free Dirac field, functional equations and corresponding many particle functionals can be derived. To establish a functional quantum theory, a physical interpretation of the functionals is required. It is provided by a mapping of the physical Hilbert space into an appropriate functional Hilbert space, which is introduced here. Mathematical details, especially the problems connected with anticommuting functional sources are treated in the appendices.
Level-crossing-Experimente in angeregten Termen des Lu I zur Untersuchung der Hyperfeinstruktur von 175 Lu / Hyperfine Structure Investigations of Excited States of Lu I by Means of the Level-crossing Method
Authors: Göbel L. H.
Published: February 2015

The magnetic dipol and the electric quadrupol interaction constants in the excited electronic states 5d6s6p (1D) 2D3/2 and 5d6s6p (1D) 2F5/2 of 175Lu I in natural isotopic abundance were investigated. The measurement was performed by resonance scattering of light with wavelengths λ = 4518.57 Å and λ = 3567.84 Å on a lutetium atomic beam. The following hyperfine structure constants were obtained:

B/A{(1D) 2D3/2} = +0.34704(80) ; A{(1D) 2D3/2} =-1313.34(50) gJ/0.80 MHz;

B{(1D) 2D3/2} =- 455.8(1.2) gJ/0.80 MHz; B/A{(1D) 2F5/2} = +9.7883(37) ; A{(1D) 2F5/2} =+ 351.864(56) gJ MHz;

B{(1D) 2F5/2} = + 3444.2 (1.9) gJ MHz.

The signs of the interaction constants were determined by examinations of these lines in a Fabry- Perot-interferometer. The lifetimes of the investigated states were found as follows:

τ{(1D) 2D3/2} = (4.9 ± 0.1) · 10-8 s; τ{(1D) 2F5/2) = (1.2 ± 0.1) · 10-8 s.

From these the oscillatorstrengths were deduced:

ƒ(3567.8 Å) = (1.7 + 0.2) · 10-1; ƒ(3841.2 Å) = (5.6 + 0.8) · 10-2;

ƒ(4518.6 Å) = (6.3 ± 0.1) · 10-2; ƒ(4967.5 Å) < 3 · 10-4.
Das Spektrum der verzögerten Fluoreszenz in Anthracen-und Naphthalin-Kristallen
Authors: Benz K. W. , Hacker W. , Wolf H. C.
Published: February 2015

The spectra of delayed fluorescence of high purity anthracene and naphthalene crystals have been measured as a function of temperature. Below 50 °K they are very different from the spectra of prompt fluorescence. The spectra of delayed fluorescence are the superposition of three types of subspectra: different X-traps-spectra, a broad continuum, and the pure crystal spectrum. From the temperature dependence of the relative intensities of these spectra one can measure the trap depth. - It is shown that the delayed fluorescence is at least 100 times more sensitive against traps and guest molecules than the prompt fluorescence. This is demonstrated using naphthalene-anthracene mixed crystals.
Infrarotspektren von Adsorptionskomplexen des Kohlenmonoxids auf Magnesiumoxid
Authors: Kölbel H. , Ralek M. , Jírů P.
Published: February 2015

Bei der Wechselwirkung des Kohlenmonoxids mit Magnesiumoxid ist selbst bei niedrigen Temperaturen der Ablauf der Boudouard-Reaktion unter Bildung von Kohlendioxid und elementarem Kohlenstoff zu beobachten.

Kohlenmonoxid und Kohlendioxid werden an der Oberfläche des Magnesiumoxids adsorbiert, wobei sich verschiedene Karbonatkomplexe ausbilden, die sich in ihrer Stabilität unterscheiden. Bikarbonatkomplexe entstehen durch eine Wechselwirkung zwischen Kohlendioxid und OHGruppen auf dem Magnesiumoxid.

Als stabilster Komplex erwies sich der Monodentatkarbonat-Komplex.

Bei Anwesenheit von Wasserstoff im System erfolgt eine Hydrierung des Kohlenmonoxids zu an der Oberfläche des MgO gebundenen Kohlenwasserstoffkomplexen.
Methode zur quantitativen Auswertung der Röntgen-Kleinwinkelstreukurven von geschmolzenen binären Legierungen
Authors: Steeb Siegfried
Published: February 2015

A method is given for calculating from the absolute intensities of the X-Ray small angle scattering the concentration and atomic composition of clusters in binary molten alloys. For the alloy with 30 a/o Sn and 70 a/o Al it is shown that at least two models exist. A decision between these two models cannot be given at the moment.

First model: Particles consist of tin atoms only. Mean particle distance 28 to 36 Å. Diameter of particles 10 Å. Density 6.5 g/cm3. Particle concentration in the melt 2.42 a/o. Mean atomic weight of the matrix atoms 52.89. Density of matrix 3.97 g/cm3. 28.27 a/o of the matrix consist of Sn, 71.73 a/o of Al. 27.58 a/o of the Sn is contained in the matrix.

This model is in agreement with the measured increase of cluster diameter with increasing tin concentration.

Second model: Particles consist of Al atoms only. Mean particle distance 18 to 23 Å. Diameter of particles 10 Å. Particle density 2.37 g/cm3. Particle concentration in the melt 7.56 a/o. Mean atomic weight of the matrix atoms 56.74. Density of matrix 4.17 g/cm3. 32.45 a/o of the matrix consist of Sn, 67.55 a/o of Al. 62.44 a/o of the Al is contained in the matrix.

This model is in agreement with the phase diagram. In this case, the Al-clusters would be preformed nuclei in the melt which lead to primary precipitation of pure aluminum during the solidification process.
Das Mikrowellenspektrum von Tert.-Butyljodid Die Analyse von Rotationsspektren mit Quadrupol-Hyperfeinstruktur
Authors: Winkle W. , Hartmann H.
Published: February 2015

Es wird das Mikrowellenspektrum eines symmetrischen Kreisels (tert.-Butyljodid) untersucht, in dem sich die HFS-Komponenten des Schwingungsgrundzustandes mit denen einiger angeregten Vibrationszustände überlagern. Dabei gelingt es, eine allgemeine Methode zur Analyse eines mit den genannten Schwierigkeiten behafteten Spektrums zu entwickeln. Die Auswertung ergibt im Falle des tert.-Butyljodids folgende Konstanten:

e Q q = -1709,5 ± 5,5 MHz, B = 1560,60 ± 0,01 MHz, DJ = 0,20 ± 0,10 kHz, DJK = 0,70 ± 0,07 kHz, rC-J = 2,190 ± 0,005 Å.
Kohärente Kleinwinkelstreuung hochenergetischer Pi-Mesonen an leichten Kernen ( 3He und 4 He)
Authors: Baier Hans
Published: February 2015

The paper discusses recently obtained (theoretical) results on the coherent small angle elastic scattering of high energy pions on the nuclei 3 He and 4 He. Starting with the full suitably parametrized spin- and isospindependent pion-nucleon amplitude for pion laboratory energies between 0.826 and 2.01 GeV the Glauber’s plural scattering formula has been applied to derive the angular distribution of scattered pions. A concise report on the use of coherent high energy processes in the investigation of the nuclear structure and the hadron-nucleon scattering amplitude is given. The advantages and shortcomings as well as possible generalizations of the plural scattering model are outlined. The formalism applied to derive results on the structure of 3 He and 4 He and the conclusions drawn from the results on pion-helium scattering are presented in detail. It has been shown that an effective pion nucleon amplitude may safely replace the full amplitude in the present context and in the energy region mentioned above.
Thermoelectric Properties in Silver Bromide-Alkali Bromide Fused Mixtures
Authors: Pezzati Elisabetta
Published: February 2015

Using a silver electrode thermocell, the initial thermoelectric power of the molten salt mixtures (Ag + Me)Br (Me=Li, Na, K, Rb, Cs) has been measured around 700 °C.

These data enable to obtain relative values of the heats of transport for the alkali cations in pure bromides and also to discuss the behaviour of the mixtures in respect to the heat and electricity transport. Finally a comparison is made with the correspondent values obtained for the alkali chlorides.
Messung der Halbwertszeiten von 60 Co, 137 Cs und 133 Ba
Authors: Walz K. F. , Weiss H. M.
Published: February 2015

The half-lifes of 60 Co, 137 Cs and 133 Ba have been evaluated from measurements of the activities of samples against the activity of a 226 Ra-standard by means of a 4 π-γ-ionization chamber during a period of about 3 years. A least squares fit together with corrections for the decay of 226 Ra, contaminations, and saturation defects leads to the following results:

60 Co: T1/2 = (5,2719 ± 0,0011) a;

133 Ba: T1/2 = (10,352 ± 0,040) a;

137 Cs: T1/2 = (29,901 ± 0,045) a.
Zusammenstellung der Koeffizienten für die Anpassung komplexer atomarer Streufaktoren für schnelle Elektronen durch Polynome 1. Mitteilung: Hartree-Fock-Fall
Authors: Hasse Joachim
Published: February 2015

In der Arbeit werden Formeln und Koeffizienten angegeben, um die Beträge und Phasen der komplexen Streufaktoren für konstante Beschleunigungsspannungen 40, 60, 80, 100, 120 kV und spannungsunabhängig zwischen 40 und 120 kV für Atome der Kernladungszahlen 1 - 36 zu berech-nen.
Induced Nonradiative Transitions in Benzene
Authors: Eastman J. W.
Published: February 2015

A nonradiative electronic transition in benzene occurs at about 2400 cm -1 above the zero-point vibration of the 1B2u electronic state. The rate-determining step may be the vibrational relaxation of the product or the nonradiative transition itself. The rate of the latter is limited to 108 < kAC < 1011 sec-1 in the vapor at 100 torr and kAC ~ 1012 sec-1 in liquids. There are also limiting values in liquids for the threshold energy and the rate of vibrational relaxation of the initial state.

In liquid solutions, the observed transition rate increases with increasing intermolecular force, but it is not increased by alkyl substitutions. Symmetry perturbation and other sources of solventinduced transitions are discussed. Also, means are suggested by which it may be possible to catalyse the formation of benzvalene.
Nichtlokale Elastizitätstheorie der Ionenkristalle vom Typ A+B-
Authors: Kessel D. , Kröner E.
Published: February 2015

The concept of non-local elastic response is explained. Neglecting retardation effects, the nonlocal elasticity theory of ionic crystals of type A+B- is derived from the atomic lattice theory by means of the Euler-Maclaurin continuization. The electric part of the theory is comprised in material tensor functions which can be calculated from the long range coupling functions (interatomic potentials). The coupling functions are obtained classically on the basis of Coulomb's law and given in ordinary and Fourier space representation. From these functions the optical and acoustical phonon dispersion curves are calculated.

The theory developed here is intended to replace the atomic lattice theory in situations where the lattices sums of the atomic theory are unmanageable
Current Fluctuations of Hot Electrons
Authors: Friedmann A. , Fazakas A. B.
Published: February 2015

In order to calculate the spectral density of current fluctuations in a high d. c. electrical field, a method using the one-electron density matrix is proposed. The nonperturbed problem is considered to be that of the electrons in an external field. The other interactions of electrons are expressed by means of a relaxation time matrix. To fit the expression of the current, given by the Boltzmannian formalism, a form of the diagonal terms of this matrix for electron-phonon interaction is suggested and closed formulae for the current fluctuations spectrum are obtained
Thermal Expansion of Alkali Sulphate Mixtures
Authors: Jansson Bert , Sjoblom Carl-Axel
Published: February 2015

The linear thermal expansivities of polycrystalline samples of mixtures of Li2SO4 with K2SO4 and with Na2SO4 have been measured with a “Fused-Quarz Tube” apparatus 1. Phase transitions are accompanied by changes in the expansion coefficient and also by volume changes. The observed expansion coefficient is constant over wide temperature intervals. Simple crystal structures show higher expansivities than more complex structures. The “pre-melting” phenomenon in Li2SO4 does not measurably influence the thermal expansion. A method has been devised to correct the observations for the plastic flow of the crystals close to the melting points
Broadening of the He II Line λ=4686 Å in a Plasma
Authors: Bogen P.
Published: February 2015

The profile of the He II λ = 4686 Å line has been measured in a plasma with an electron density of 5.5-1017 cm-3 and a temperature of 6 - 104 °K. The measured halfwidth is consistent with that predicted by the Griem and Shen theory. On the far wings the intensity approaches the value expected when ions and electrons are treated by the static theory, although the electrons are far outside the static broadening regime
Resonanz-Raman-Effekt von Thiocyanatkomplexen einiger Übergangsmetalle
Authors: Krasser W. , Nürnberg H. W.
Published: February 2015

The thiocyanates of the transition metals iron, cobalt, copper as well as of rhenium and of tech-netium appear in solution as strongly coloured complexes. The resonance raman bands in the sol-vent acetonitrile are investigated. To achieve an unambiguous identification the infrared spectra were recorded too. The change in position and structure of the acetonitrile bands indicates strong complexation of iron, cobalt and copper with acetonitrile, thus indicating the existence of mixed acetonitrile-thiocyanate complexes. The resonance raman spectra of the rhenium-and technetium-thiocyanates present as tetramethyl ammonium salts show however no raman-and infrared-bands of complexed acetonitrile molecules.

In the raman spectrum of the thiocyanates of iron, cobalt and copper mainly the totally sym-metric C≡N, S-C, Me-S and Me-N valence vibrations are observed, among which the S-C vibration shows a remarkably high intensity. Besides, a series of bands is obtained which is inter-preted partly as caused by decay products, and partly as bands of complexed acetonitrile. The thiocyanates of rhenium and of technetium show the three possible valence vibrations only. The high frequency of the S-C valence indicates the N-coordination of the thiocyanate group.
Doppelresonanzuntersuchung in angeregten Zuständen von Lu I/ Double Resonance Investigation in Excited States of Lu I
Authors: Göbel L. H.
Published: February 2015

In a double resonance experiment the gJ-factor of the excited state of Lu I 5d6s6p (1D) 2D3/2 , has been measured: gJ {(1D)2D3/2} = 0.874(5). This value deviates considerably from its value in Russel- Saunders coupling. The lifetime of this state is (4.88 ± 0.10) x 10-8 s.
Integrale Wirkungsquerschnitte der Reaktion 11B(n,α)8Li(β)8Be*(2α)/ Integral Cross Sections of the Reaction 11B(n,α)8Li(β)8Be*(2α)
Authors: Scobel W. , Bormann M.
Published: February 2015

The excitation function of the reaction 11B(n,α)8Li(β)8Be*(2α) has been measured for neutrons with energies between 15.5 and 19 MeV. The reaction was identified by the α-decay of the 8Be* occurring with the lifetime of the residual nucleus 8Li. The detector for the α-particles was a gridded ionization chamber.
Light Emission in the VUV by Dissociative Excitation of CO2 with Low-Energy Electrons
Authors: Sroka W.
Published: February 2015

The CO2 molecule is dissociated in a single step process by an electron into excited atoms or ions which emit a radiation in the vuv. There are 34 radiation components from C II, O II, C I, O I and CO in the wavelength region from 450 Å to 1450 Å. We have measured the excitation functions and the dependencies of the line intensity on beam current and pressure. The excitation functions of most of the O I multiplets show a pronounced structure at about 20 to 50 eV. Immediately above the first critical potential these levels are populated via partial dissociation of CO2. About 2% of the ions (C II and O II) formed by dissociative ionization are excited and emit a radiation in the vuv.
An Apparatus for Non Destructive Study of Atom Transport in Liquids
Authors: Larsson S. , Broman L. , Roxbergh C. , Lodding A.
Published: February 2015

A description is given of a method developed for diffusion and electrotransport measurements in liquids, which permits several successive readings on a sample in uninterrupted anneal. Errors from solidification and sectioning are avoided, and the reproducibility of measured diffusion coefficients is better than two percent. Experimental results are given for gallium self-diffusion. The present apparatus can be conveniently applied to many liquids solidifying below some 280 °C utilizing gamma tracers with energies in the range 0.2 - 2.0 MeV. The design can be modified for higher temperatures.
Miscibility Gaps in Fused Salts
Authors: Flor Giorgio , Sinistri Cesare
Published: February 2015

The two families of systems formed by silver halides with alkali Chromates and tungstates have been systematically investigated in order to bring into evidence possible demixing phenomena. It has been found that silver chloride demixes with lithium Chromate and tungstate and with sodium tungstate; silver bromide demixes with lithium and sodium Chromates and tungstates; silver iodide demixes with lithium, sodium and potassium Chromates and tungstates. Moreover the whole compo-sition square of the ternary reciprocal system Ag, Na/Cl, WO4 has been investigated.

The tendency to demix in these systems has been discussed on the basis of the characteristics of the ions.
Untersuchung der Diffusion von Wasserstoff in Pd- und Pd/Ag-Legierungen mit einer Stromstoß-Methode
Authors: Züchner H.
Published: February 2015

Diffusion coefficients of H in Pd and Pd/Ag-alloys were determined at low hydrogen concentration and at temperatures between 0 and 60 °C by a new electrochemical pulse method making use of time-lag-techniques.

The preexponential factor D0 decreases slightly with rising silver content (x=weight % Ag/100) : log D0=-2.409-1.0 x.

The activation energy runs through a flat minimum at about 15% Ag. Its dependence on the silver content of the alloy 0 ≦ x ⪅ 0.5 can be expressed empirically by

E=5750-5285 x+19100 x2 cal/mol.
Notizen: Nuclear Quadrupole Resonance of N14 in Pyridine Complexes
Authors: Ha Tae-Kyu , O'Konski C.T.
Published: February 2015

Shifts in the nuclear quadrupole coupling are detected for N14 in pyridine complexes by pure nuclear quadrupole resonance spectroscopy (NQR). These are compared with values obtained by the Townes-Dailey method using a simple molecular-orbital (MO) calculation for the pyridine-pyrrole system.
Low-Energy Electron Diffraction from Ag(111): Intensity-versus-Energy Curves and Absolute Intensity of the (00) Beam
Authors: Lagally Max G.
Published: February 2015

The intensity of the (00) beam of a (111) surface of Ag has been measured with a Faraday cage as a function of the energy of the incident beam (10 < E < 280 eV), the grazing angle of incidence (46.5° < φ < 83.5°), two azimuths differing by 180°, and the temperature. The I vs E curves, when compared with data for Ag ( 111 ) of other workers who have used different methods of surface preparation, show good agreement in the structure over the whole range of incident angles, indicating that LEED is not strongly sensitive to surface condition. The I vs E curves for the two azimuths are identical, a necessary result of the reciprocity theorem. For comparison with the I vs E structure, a complete 3-beam geometric model is used. This differs from a simple Ewald construction in that it considers also the Bragg conditions between intermediate beams and the final beam. It also requires that there be no difference in the effect of intermediate forward and backward scattered beams. It is shown that the number of possible beams is much too large even at low energies to make positive identification of any structure in the I vs E curves. A comparison with a rigorous multiple-scattering theory yields agreement in the number and position of peaks, but not in heights and widths of peaks. The possibility of comparison of absolute intensities in theory and experiment is investigated and an attempt is made to remove the major differences. Intensity vs temperature measurements are made at closely spaced energies in order to extract the rigid-lattice scattering. Correction of this intensity for surface plasma losses leads finally to maximum scattered intensities of 2% at 100 eV, 10% at 60 eV, and up to 40% at energies below 20 eV.
Dynamic Polarization, Molecular Motion and Solvent Effects in Several Organic Solutions as Studied by Proton-Electron Double Resonance
Authors: Müller-Warmuth W. , Öztekin Erol , Vilhjalmsson Reynir , Yalçiner Aytaç
Published: February 2015

Dynamic proton polarization in several free radical solutions has been studied systematically with different radicals at five widely separated magnetic field strengths and at various temperatures. Normally, in organic solutions the dynamic enhancements of the solvent proton resonances decay with increasing field and decreasing temperature. Scalar proton-electron coupling has only been observed in exceptional cases. The spectral intensity functions describing the experimental behaviour are derived from the dipolar interaction whose time dependence is in the first place due to translational diffusion of individual molecules. In addition, a certain solvation effect has to be taken into account. Strong solvation occurs in solutions of hydroxyl containing solvents with nitroxide radicals. In this case, the dynamic proton polarization appears to be quite different. As an example, solutions of tetramethyl piperidineoxyl in acetic acid have been examined in more detail. The results are explained in terms of hydrogen bridged solvates. The important motional mechanism that modulates the proton-electron interaction switches from “translation” to “rotation”, and electron spin density is temporarily transferred to the solvent molecule.
Hindered Rotation in Biphenyl According to a Selfconsistent Steric Analysis
Authors: Gołbiewski A. , Parczewski A.
Published: February 2015

A selfconsistent steric conformation analysis is applied to the ground state, first excited state and the ionic state of biphenyl in terms of the internal rotation angle. The calculated barrier of rotation through Θ = o° is equal to 3.1 kcal/mole. In the case of the isolated anion the twisting angle equal to 26° was obtained. In the case of solutions the angle is 15 - 19°, the value following from an analysis of the EPR data published by Möbius. The electronic absorption spectrum is discussed in terms of the SCF CI method. The results are compared with other recent calculations.
Quantenchemische und spektroskopische Untersuchungen an Porphyrinen
Authors: Knop J.V. , Knop A.
Published: February 2015

Zur Deutung der Elektronenanregungsspektren der freien Base Porphin und des Zn-Porphins wurden SCF-CI-Berechnungen mit Berücksichtigung aller 143 einfach angeregten Konfigurationen durchgeführt.

Es konnten neue Gesichtspunkte zur Zuordnung der Elektronenübergänge im Absorptionsspek-trum gewonnen werden. Ihre Lage, Intensität und Polarisation stehen in sehr guter Übereinstim-mung mit dem Experiment.

Ferner konnten die von Woodward auf experimentellem Wege gemachten, sehr präzisen Voraus-sagen über die Ladungsverteilung im Porphin voll bestätigt werden.
Quantenchemische und spektroskopische Untersuchungen an Porphyrinen
Authors: Knop J.V. , Knop A.
Published: February 2015

Im Anschluß an die Deutung der Elektronenanregungsspektren der freien Base Porphin und des Zn-Porphins wurden audi SCF-CI-Berechnungen der mono-und divalenten Ionen des Porphins, unter Berücksichtigung aller 143 einfach angeregten Konfigurationen, durchgeführt.

Soweit experimentelles Material vorhanden war, konnte eine befriedigende Übereinstimmung mit den theoretischen Ergebnissen erzielt werden.
Notizen: Centrifugal and Gravitational Cells Containing Molten Salts with Three Ion Constituents
Authors: Richter Joachim
Published: February 2015

Since recently 1 the first experimental data on cen-trifugal and gravitational cells containing molten salts have been published, the rigorous derivation of the formulae for the EMF of this type of galvanic cells will now be given. The corresponding formulae for aqueous electrolyte solutions have been obtained by MILLER 2 and indepen-dently by SCHÖNERT 3 who also included polyelectro-lyte solutions. Both authors refer to experimental in-vestigations of TOLMAN 4 , GRINNEL and KOENIG 5 ,
The Role of Starting Potential in the Kinetics of Chemical Reactions under Electrodeless Discharge
Authors: Ao T.S.R , Patil A.
Published: February 2015

It has been shown that in kinetically first order gas phase reactions occuring under electric discharge, such as the decomposition of N2O, the application, at various initial pressures, of the same multiple of the respective starting potential ensures that the reaction occurs at the same specific rate.
The Mößbauer Effect of the 129 keV Transition in 195Pt
Authors: Wolbeck B. , Zioutas K .
Published: February 2015

The Mößbauer effect of the 129 keV transition in 195Pt has been observed. By use of a Ge(Li) detector any contribution from the strong 99 keV Mößbauer line could be eliminated. The width of the resonance absorption line corresponds to the natural line width. We derived from the magnitude of the observed Mößbauer effect the branching ratio in the decay of the 129 keV level as I (129)/I (31) = ( 5.7 ± 1.6)% .
Heating of Laser Produced Plasmas Generated at Plane Solid Targets I. Theory
Authors: Theory I. , Puell H.
Published: February 2015

A hydrodynamic model for the heating of a plasma generated by the interaction of an intense giant laser pulse with a plane, solid target is developed. It is shown that in the case of nanosecond light pulses and a finite focal spot diameter, the plasma production may be considered as a steady state problem. Expressions for the electron temperature, the expansion energy of the ions, and the total particle number in the plasma as a function of the incoming light intensity are derived. An estimate of the ion temperature is discussed.
Temperature and Expansion Energy of Laser Produced Plasmas II. Experiments
Authors: Puell H. , Neusser H.J. , Kaiser W.
Published: February 2015

Experiments on laser produced plasmas with light intensities between 2·1011 and 5·1012 W/cm2 are reported. Measurements of the electron temperature and the expansion energy were performed. In the case of LiD targets the highest temperature observed was 200 eV. Using carbon targets a maximum temperature of 330 eV was measured. The corresponding expansion energies reach values as high as 13 keV. The experimental results are in good agreement with a stationary, hydrodynamic theory. We conclude from our data that in our LiD and C plasmas ions and electrons have the same temperature.
Über den Hamilton-Operator der Schwingungs-Rotations-Bewegung linearer Moleküle / On the Vibration-Rotation Hamiltonian of Linear Molecules
Authors: Strey G .
Published: February 2015

A closed expression for the vibration-rotation hamiltonian of linear molecules is derived and discussed. By use of the commutation relations and sum rules this expression is then rearranged to a form similar to that of WATSON1 for nonlinear molecules.
Partielle Interferenz-und partielle Atomverteilungsfunktionen sowie elektrischer Widerstand von geschmolzenen Magnesium—Zinn-Legierungen
Authors: Bühner H.F. , Steeb S.
Published: February 2015

From measured intensity functions, published in a previous paper, partial interference functions, partial pair correlation functions, partial atomic distribution functions, and partial coordination numbers were calculated and discussed. According to the theory of Faber and Ziman, the electrical resistivity of molten Mg-Sn alloys was calculated from the partial interference functions and from pseudopotentials reported by Animalu and Heine. The calculated values, being normalized to the resistivity of the molten components, are in good agreement with values measured by a rotating field method.

The partial interference functions are derived by the assumption of independency of concentration. This assumption is proved by discussion of the partial coordination numbers and the results of electrical resistivity determinations.
Untersuchung zur Keimbildung von Gold auf NaCl-Einkristallspaltflächen im Ultrahochvakuum
Authors: Schmeisser H. , Harsdorff M .
Published: February 2015

The present paper presents the results of an investigation of the nucleation process during the formation of evaporated gold films on UHV cleaved rocksalt single crystals. The dependence of the nucleation rate and the sticking coefficient on the substrate temperature and deposition rate has been studied in detail. The results are interpreted in terms of a kinetic nucleation model. It is shown that this interpretation based upon atomistic considerations is successful and allows to determine the main model parameters, such as the binding energy of the single atom to the substrate or the activation energy of surface diffusion. An upper limit can be given for the jump distance of the single atom.
Determination of Vibrational Resonance Parameters in the Spectra of Polyatomic Molecules
Authors: Wlnther F.
Published: February 2015

An approximation method for determination of vibrational resonance parameters, based upon the invariance of anharmonicity constants against phase changes, is described. Several examples, including resonances in the spectra of CO2, OCN-, CH3I, and some 1,1-disubstituted ethylenes, are given.
The Electrical Conductivity and Density of the Molten Systems Li2S04 —ZnSO4 and Na2SO4 —ZnSO4
Authors: Josefson Ann-Mari , Kvist Arnold
Published: February 2015

Zinc sulphate decomposes upon melting. Molten Li2SO4 -ZnSO4 and Na2SO4 -ZnSO4 are thermally stable with up to 80 mole% of ZnSO4 . We have measured the density and electrical conductivity of these melts. By extrapolation we have calculated the density (ϱ) and molar electrical conductivity (Λ) of pure molten zinc sulphate and we have obtained (t in °C)

ϱZnSO4 = 3.463 - 0.470 x 10-3 t(g/cm3),

ΛZnSO4 = 0.0950 t-35.4 (cm2/ohm, mole).
Nuclear Magnetic Relaxation in a Gas of Regular Molecules
Authors: Mccourt F.R. , Hess S.
Published: February 2015

Nuclear magnetic relaxation (NMR) in a gas of regular (tetrahedral and octahedral) molecules from the point of view of the kinetic theory of transport and relaxation processes based on the Waldmann-Snider equation is considered. A simple expression is obtained for the spin-rotation interaction based on considerations of the molecular symmetry. The form of the spin-rotation coupling which contains, in addition to the so-called "scalar" coupling constant, also a scalar anisotropy part, ⊿c, of the spin-rotation coupling tensor determines, along with the collision operator, the form to be taken by an expansion of the nonequilibrium part of the distribution function-density matrix of the gas. Solutions of the set of coupled differential equations which follow upon application of the moment method to the linearized Waldmann-Snider equation lead to the Bloch equations which define the "spin-lattice" and transverse relaxation times in the gas. Those obtained here are com-parable with those obtained using correlation function theory. However, in this work, due to explicit consideration of the molecular symmetry, it is shown that the "effective" spin-rotation coupling coefficient found in tetrahedral and octahedral molecules is not the same and depends in a simple way on the number of equivalent spins in the molecule.
Zur experimentellen Prüfung des theoretischen Ausdrucks für die Rydberg-Konstante
Authors: Zygan H.
Published: February 2015

Berechnungen der fundamentalen Naturkonstanten aus geeigneten Präzisionsmessungen führen zu dem Ergebnis, daß sich die Werte der Elementarladung, der Elektronenmasse, des Planckschen Wirkungsquantums und der Avogadro-Konstante ebenso wie die daraus berechneten Werte der Sommerfeldschen Feinstrukturkonstante a um etwa 0,2%o unterscheiden, wenn diese Werte einmal nur aus solchen Präzisionsmessungen, die von der Theorie des Einelektronen-Atoms keinen Gebrauch machen und ein zweites Mal mit Benutzung des gemessenen Wertes für die Rydberg-Konstante berechnet werden. Zwischen der gemessenen Rydberg-Konstante und dem theoretischen Wert, der sich aus den ohne Benutzung der Atomtheorie erhaltenen Naturkonstanten errechnet, wird ein Unterschied von über 0,4%o gefunden.

Zur endgültigen experimentellen Bestätigung oder Auflösung dieser Diskrepanz wird eine neue Mehode für die direkte Präzisionsmessung der Elementarladung angegeben.
Anorganische Flüssigkeitslaser
Authors: Weichselgartner H. , Perchermeier J.
Published: February 2015

Anorganische Flüssigkeitslaser basieren heute auf Phosphoroxychlorid, POCl3 , als Lösungsmittel für verschiedene Neodymsalze. Je nach verwendeten Lewis-Säuren, beispielsweise Aluminiumchlorid, liegen die Fluoreszenzlebensdauern bei Werten um 330 μsec. Es werden neue Lösungsmittel, Neo-dymverbindungen und Lewis-Säuren und das Addukt Nd2[(SnCl6)2-]3 beschrieben.