bluuebunny/crossref_metadata_2025 huggingface dataset:
Bestimmung der Molekülstruktur des N-Chlor-Schwefeldifluoridimids mit Hilfe der Elektronenbeugung an Gasen
Authors: Haase J. , Oberhammer H. , Zeil W. , Glemser O. , Mews R.
Published: February 2015

Mit Hilfe der Elektronenbeugung an Gasen wurde die Mo-lekülstruktur des N-Chlor-Schwefeldifluoridimids bestimmt. Aus drei Strukturbestimmungen ergaben sich folgende Werte für die geometrischen Molekülparameter:

Cl - N = 1,723 ± 0,004 Å; ∢ ClNS = 120,0 ± 0,2 °;

S - N = 1,476 ± 0,003 Å; ∢ NSF = 111,2 ± 0,1 °;

S - F = 1,596 ± 0,002 Å; ∢ FSF = 89,3 ± 0,2 °.

Die Ergebnisse für die Schwingungsamplituden werden angegeben.
Zur Interpretation der Elektronenverteilungen nach dem SCF-MO-P(LCGO)-Verfahren
Authors: Preuss H.
Published: February 2015

Abastract

Nach einem kurzen Überblick über das SCF-MO-P (LCGO)-Verfahren werden die verschiedenen Möglichkeiten diskutiert, die sich aus einer Analyse der Elektronenverteilungen ergeben. In diesem Zusammenhang werden bestimmte graphische Darstellungen (Diagramme) angegeben.
Anwendung der Eigenkanal-Theorie auf die Coulomb-Anregung von Atomkernen
Authors: Greiner Bernd
Published: February 2015

The eigenchannel method is applied to Coulomb excitation. The formalism is developed and the involved matrix elements are calculated analytically. Estimates for the density of internal states are given. This method should prove fruitful for the calculation of quantum mechanical corrections of the semi-classical treatment of Coulomb excitation.
Surface Dependent Geometrical Resonance of Superconductors
Authors: Schattke W.
Published: February 2015

The nonlocal integral equation obtained previously allows the determination of the amplitude of Geometrical Resonances in the McMillan-Anderson model. Surface conditions are defined by an adjustable parameter p which is fixed to fit the critical thickness measurements of the Proximity Effect.
Bestimmung der Kraftkonstanten der Hexafluoro-Komplexe des Technetium(IV) und Rhenium(IV) auf der Basis der D4h-Symmetrie
Authors: Krasser Wolfgang , Schwochau Klaus
Published: February 2015

The infrared spectra of potassium and cesium hexafluorotechnetate (IV) and -rhenate(IV) show a D4h-distortion of the octahedral complex ions. The splitting of degeneracies is not due to site symmetry. The linear combinations of the force constants of the irreducible representations A2u and Eu are determined in the valence force field on the basis of D4h-symmetry. As expected the force constants of stretching vibrations of [TcF6]-- are then smaller than those of [ReF6]--.
Diffusion in binären Gemischen von H2, HD und D2 bei 24 °C / Diffusion in Binary Mixtures of H2, HD and D2 at 24 °C
Authors: Müller K. P. , Klemm A.
Published: February 2015

Diffusion in a cylinder followed by catarometric analysis allowed to measure the inter-diffusion coefficient D in the systems H2-HD, H2-D2 and HD-D2 at 24 °C and 760 Torr with an estimated error of ±1% . A dependence of D on concentration did not show up.

A least square fit combining the new measurements with less accurate earlier ones on system containing tritium, yields the three coefficients of the expansion

(√μ̅D)I II = 0.0006 mI II-0.023(m2
13-m2
24) + 0.010 (m2
AC + m2
BD - m2
ac - m2
bd).

μ is the reduced mass of the two molecules of a mixture, and in general xik=(xi-xk) / (xi + xk). Roman numbers as indices indicate mixtures, arabic ones molecules and letters atoms. As for the masses mI=m1 + m3, mII=m2+m4, m1= mA+mC, m3= mB + mD,m2 + mc, m4=mb+md.

The signs of the first two coefficients in the expansion agree with the second Chapan-Enskog approximation, and that of the third coefficient with the model of loaded spheres.
Die Oxidationsgeschwindigkeit von Legierungen des Kupfers mit Aluminium, Chrom und Mangan
Authors: Frohberg M. G. , Pötschke J. , Mathew P. M.
Published: February 2015

Die Temperaturabhängigkeit der Geschwindigkeitskonstanten für die innere, äußere und gesamte Oxidation wurde im Bereich zwischen 900 und 1000 °C für Legierungen des Kupfers mit Aluminium, Chrom und Mangan experimentell bestimmt.
Zur Rayleigh-Taylor-Instabilität eines rotierenden Wasserstofflichtbogens im axialen Magnetfeld
Authors: Döbele H. F.
Published: February 2015

The Rayleigh-Taylor instability of a rotating hydrogen arc in an axial magnetic field is investigated with allowance for electrical conduction, heat conduction and viscosity. The r-depending part of the perturbation was assumed to be in the form of a half-period of a standing wave. The corresponding dispersion relation is derived in the WKB-approximation and is solved numerically. In contrast with the case without dissipation, the frequencies and growth rates of the different modes depend on the parameters of the unperturbed plasma column. The calculation shows, in qualitative agreement with the experiment, that with increasing magnetic field the highest growth rate passes successively to the next higher mode.
Hydrogen Plasma Production by Giant Pulse Lasers
Authors: Mulser Peter
Published: February 2015

The problem of interaction of an intense laser beam with solid hydrogen is theoretically investigated in a one-dimensional plane geometry. The time dependent distributions of density, temperature and velocity of the produced plasma as well as those of the solid are found by numerical solution of the hydrodynamic equations for various laser powers. The maximum temperature can be approximately expressed in closed form as a function of the laser intensity and time. The calculations allow for the influence of thermal conduction and viscosity. At laser intensities above 1.8 x 1011 W/cm2 the plasma frequency rises above that of the laser in the transition sheath between the hot plasma and the cold solid. The problem of absorption and reflection of laser radiation in this region is investigated.
Die Dampfdruckkurve von In2S3
Authors: Bollmann G. , Nelkowski H.
Published: February 2015

The temperature dependence of the In2S3 vapour pressure was investigated by means of the effusion method using radioactive In-116. In the range from 900 - 1200 K the pressure is given by log p = - 1.118 · 104/T + 9.23.
Das effektive Trägheitsmoment im quantenmechanischen Dreikörperproblem
Authors: Letz H. , Ruder H. , Volz H.
Published: February 2015

The method of "specific decoupling", as described in two earlier papers, is applied to special forms of wave functions of the 3-body-problem. The internal frame of reference, connected with a collective rotational motion of the system, is determined by solution of the basic differential equation. An exact expression for the effective moment of inertia is given and evaluated. The results confirm the validity of former variational calculations
Spectrum of the Depolarized Rayleigh Light Scattered by Gases of Linear Molecules
Authors: Hess Siegfried
Published: February 2015

The spectrum of the depolarized Rayleigh light scattered by a gas of linear molecules is calculated by a kinetic theory approach based on the Waldman-Snider equation. Collisional and diffusional broadening are studied. The line width is related to relaxation coefficients which are collision brackets obtained from the linearized Waldmann-Snider collision term involving the binary molecular scattering amplitude and its adjoint. It is shown under which conditions the relaxation coefficients characterizing the line width can be compared with data obtained from Sentfleben- Beenakker effect and nuclear magnetic relaxation measurements
Nuclear Quadrupole Resonance of 35Cl and 37Cl in Polycrystalline LiC1O3
Authors: Kaufmann J. , Söhre F.
Published: February 2015

The nuclear quadrupole resonance (NQR) transitions of 35Cl and 37Cl have been detected in polycrystalline LiClO3 . Precision measurements have been performed at 26 °C; some preliminary investigations at different temperatures have been made
Kinetic and Potential Energy Partitioning for Antibonding Molecular Orbitals
Authors: Schmidtke Hans-Herbert
Published: February 2015

Expectation values of kinetic and potential energy are calculated for some lower antibonding orbital states of simple diatomic molecules using H2
+ and HeH2+ as test cases. Common LCAO-MO theory and a scaling procedure are applied which allow an analysis of atomic orbital interactions in terms of RUEDENBERG'S1 promotion and interference effect at various internuclear distances. Contributions to the total energy at different regions of interatomic separations are discussed in detail. A characteristic increase of the kinetic energy is observed for antibonding linear combinations at distances where chemical bonding occurs.
Molecular Force Fields of Some Selenium and Telurium Hexahalide Ions
Authors: Avasthi M. N. , Mehta M. L.
Published: February 2015

Wilson's GF matrix method has been used to evaluate all the seven independent force constants of some XY6 type ions using Müller's mathematical constraint. Mean amplitudes of vibration and Bastiansen-Morino shrinkages have also been calculated for these ions.
Lumineszenz von γ-bestrahltem Silicagel bei Sorption von Gasen: “Radiosorptionslumineszenz”
Authors: Rabe J. G. , Breitkreutz K.
Published: February 2015

Luminescence has been observed on exposure of γ-irradiated silicagel to various gases and vapours. The emission spectrum has a maximum at 450 nm and is identical with the spectrum of radiothermoluminescence (RTL) under vacuum with a peak at 55 °C. After radiosorption luminescence (RSL) at 20 °C the thermoluminescence at 55 °C is decreased. The effect of RSL shows that sorbed gases can cause recombination of charges trapped in the gel.
ESR-Untersuchung der behinderten Rotation der Acetyl-Gruppe in einigen para-X-Acetophenon-Anionradikalen
Authors: Kaminski W.
Published: February 2015

The anion radicals of para-X-acetophenone (X = NO2 , CH3 , H, Br, OCH3) were generated by electrolytic reduction in N,N-dimethylformamide solution. The temperature dependence of the ESR spectrum of para-nitroacetophenone(-) indicates restricted rotation of the acetyl group relative to the rest of the molecule. A complete line-shape analysis of the spectrum at various temperatures leads to Arrhenius-parameters Ea= (8.9 ± 0.5) kcal/mol and 10log k0=12.7±0.3. The other radical anions show magnetic nonequivalence of their meta protons up to the highest temperature at which the spectra were observable. This enables us to set a lower limit to their potential barriers of about 11 . . . 12 kcal/mol, depending on the para substituent.
Elektronen-Spin-Resonanz und optische Untersuchungen an Cr-dotierten Y-Ti-Pyrochlor-Einkristallen Y2Ti2O7
Authors: Becker Wolf-Jürgen
Published: February 2015

Single crystals of Y2Ti2O7, which crystallizes with the pyrochlore-structure, have been grown by the flux method with PbO -PbF2. The cubic lattice constant is a = (10.0896 ± 0.0014) Å. The free O II-parameter x= -0.0788 ± 0.0005 was determined from X-ray and neutron diffraction data.

The ESR spectrum of Cr-doped Y2Ti2O7 single crystals has been observed at X- and Q-band. Cr3+ occupies Ti4+-sites (Symmetry D3d). We obtained the following parameters of the spin Hamiltonian

g∥ = 1.9743 ± 0.0005, g⊥ = 1.9767 ± 0.0008 , |D| = 0.954 ± 0.007cm-1.

The optical absorption spectrum of Cr3+-doped Y-Ti-pyrochlore shows the U-band (4A2 → 4F2) at (19200 ± 100) cm-1. The R-lines have been studied with fluorescence methods:

R1-line E(2E) → 4A2 at (13 930 ± 1 ) cm-1; R2-line 2A(2E) → 4A2 at (14 002 ± 1) cm-1 . The splitting of 72 cm-1 indicates a relatively large trigonal component of the crystal field.
Das Protonenresonanzspektrum des Phosphorwasserstoffs in einem nematischen Lösungsmittel
Authors: Spiesecke H.
Published: February 2015

The analysis of the proton nmr spectrum of phosphine yields a value of 94°41′ ± 3′ for the HPH bond angle. Using the microwave determined moment of inertia IB = 6.28499 · 10-40 g · cm2 in connection with the nmr results an absolute value of 1.427 Å for the PH bond is calculated.
Ternary Lanthanide Complexes of the Type M(Hsal)3(TPX → O)2 and a Fluorescence Spectral Study of the Eu(III) Analogue
Authors: Sinha Shyama P.
Published: February 2015

Ternary lanthanide complexes of the general formula M(Hsal)3 (TPX→O)2 , where M = lanthanide (III) ion, Hsal=salicylate ion =C6H4(OH)COO- and X = P or As have been isolated as solids from the benzene phase during liquid-liquid extraction studies of M(Hsal)3 complexes with benzene solutions of TPX→O. The coordinated nature of the TPX→O ligands has been established from the observed shifts of the X → O frequency in the infrared. A lowering of the 1190 cm-1 P → O frequency where X = P , and an increase in the 885 cm-1 As → O frequency where X = As have been observed for the ternary complexes. The infrared spectra of the ternary complexes in general indicate the coordinated nature of the salicylate ions.

The luminescence spectra of Eu(Hsal)3 (TPPO)2 and Eu(Hsal)3 (TPAsO)2 complexes have also been investigated at 77 °K. Beside the emission of the characteristic red europium fluorescence due to the excitation of the complexes with near UV light, emission of a blue molecular phosphorescence from the complexes has also been observed. The fluorescence intensities of the f → f transitions are, however, weak. This point has been discussed.
Isotopic Effect on the Melting Point of Lithium Nitrate
Authors: Jansson Bert , Lundén Arnold
Published: February 2015

The techniques of segregation during normal freezing and of zone melting have been used to establish that the melting point of 6LiNO3 is higher than that of 7LiNO3. The difference is of the order of 0.03 °C. The isotope shift of the melting point is in the opposite direction of the isotope effects found previously for phase transitions in solid lithium metal and lithium sulfate. For the latter salt a recalculation based on a more accurate value for the self-diffusion coefficient shows that the temperature of transition at about 575 °C to a fee structure is about 0.08 degr. lower for 6Li2SO4 than for 7Li2SO4.
Gravimetrie Interdiffusion Studies of the NaNO3—AgNO3 and NaNO3-RbNO3 Fused Salt Mixtures
Authors: Andréasson Dan , Behn Anders , Sjöblom Carl-Axel
Published: February 2015

The interdiffusion coefficient has been measured over the whole range of compositions in the NaNO3 -AgNO3 and NaNO3 - RbNO3 molten salt mixtures, using an improved version of the gravimetric interdiffusion technique. At 340 °C the interdiffusion coefficient is about 2.3 × 10-5 cm2 s-1 in mixtures with a high NaNO3 content. It increases slightly with increasing AgNO3 content and decreases with increasing RbNOs content. Good agreement is found with data obtained with other methods. There is evidence that the interdiffusion coefficient is inversely proportional to the cation radii in the melt. Interionic friction coefficients are calculated. Only three ionic species are present in dilute solutions of AgNO3 and RbNO3 in NaNO3 but there is evidence of “complex ion formation” in dilute solutions of NaNO3 in AgNO3 and in RbNO3.
A Flute-like Plasma Instability Driven by Field Inhomogeneities
Authors: Voslamber Dietrich
Published: February 2015

We investigate the stability of ring-like plasma configurations with small Larmor radii, precessing axi-symmetrically in mirror machines. If the precession frequency increases with radius, such equilibria may be subject to a low frequency flute-like instability which is driven by field inhomogeneities rather than by the density gradient. The phase velocity of the unstable waves is twice that occurring in the case of the ordinary flute-instability. Though the physical situation is quite different from that of circular beams of charged particles, the driving mechanism shows a certain analogy to that of the negative mass instability. It is noteworthy, however, that in our case equilibria with a finite spread in the transverse particle energies may be less stable than those with zero energy spread.
Functional Quantum Theory of Scattering Processes. II
Authors: Stumpf H.
Published: February 2015

Dynamics of quantum field theory can be formulated by functional equations. To develop a complete functional quantum theory one has to describe the physical information by functional operations only. The most important physical information of elementary particle physics is the S'-matrix. In this paper the functional S'-matrix is constructed for relativistic spin 1/2 fermion scattering in nonlinear spinortheory with noncanonical relativistic Heisenberg quantization. With appropriate modifications the procedure runs on the same pattern as in the case of nonrelativistic potential scattering treated in I. Furthermore a calculational method for scattering functionals is proposed. In the appendices technical details are discussed.
Bestimmung der Molekülstruktur des Dimethylsulfonimins mit Hilfe der Elektronenbeugung an Gasen
Authors: Oberhammer Heinz , Zeil Werner
Published: February 2015

Mit Hilfe der Elektronenbeugung wurde die Molekülstruktur des Dimethylsulfonimins in der Gasphase bestimmt. Die folgenden geometrischen Molekülparameter wurden gefunden:

S - O = 1,437 ± 0,003 Å, S-N = 1,521± 0,003 Å, S-C = 1,781 ± 0,003 Å,

C - Hm = 1,083 ± 0,007 Å, N - Hi = 1,022 ± 0,018 Å,

∢ CSC = 101,6 ± 1,3°, ∢ OSN = 132,6 ± 0,9°, ∢ CSO = 106,7 ± 1,0°,

∢ CSN = 102,7 ± 1,3°, ∢ SNHi = 114,1 ± 2,4°, ∢ HmCHm = 108,8 ± 1,3°

(Hm = Methylwasserstoff, Hi = Iminwasserstoff).

Die Ergebnisse werden mit den entsprechenden Werten der isoelektronischen Verbindungen Dimethylsulfodiimin und Dimethylsulfon verglichen. Es wird versucht, die Bindungsverhältnisse in diesen drei Molekülen mit einem stark vereinfachten Modell zu beschreiben.
Molecular Diamagnetism: Uncoupled Calculations for Two Center Systems
Authors: Ludwig B. M. , Voitländer J.
Published: February 2015

For Σ1 molecules constructed from first row elements of the Periodic Table computations of the diamagnetic susceptibility and the nuclear magnetic shielding constants are reported. The method used is a gauge invariant approximation to the gauge dependent “uncoupled” perturbation theory in the Hartree-Fock scheme; the groundstate description considered is provided by the best limited MO functions.

Some emphysis is placed on methodological aspects and the role of π-electrons in this context; acceptable overall agreement with experiment is achieved, especially for the mean diamagnetic susceptibility. The phenomenon of antishielding occurring for fluorine and nitrogen nuclei is shown to depend critically upon the nodal structure of the state. A similar behaviour of the induced current density is not predicted by the semiclassical Thomas-Fermi theory, for which results are obtained too. This theory fails for principle reasons to explain the linear magnetic response of nonspherical systems.
Thermoelectric Properties in Silver Chloride-Alkali Chloride Fused Mixtures
Authors: Sinistri Cesare , Pezzati Elisabetta
Published: February 2015

The initial thermoelectric power of the molten salt mixtures (Ag + Me)Cl (Me = Li, Na, Rb, Cs) has been measured at various temperatures around 800 °C using a silver electrode thermocell. In addition the thermoelectric power of molten pure AgCl is reported.

These data have been used to obtain relative values of the heats of transport of the alkali cations in pure salts. Moreover the global behaviour of these mixtures in respect to an ideal model for the heat and electricity transport is discussed.
Composite States for Fourfermion Interactions by the Method of Broken Symmetries
Authors: Müller Harald J. W.
Published: February 2015

Composite states of quasiparticles are studied in the frame of Bopp's quantum theory of elementary particles in a lattice space. By solving the homogeneous Bethe-Salpeter equations in the combined chain and ladder approximation the theory is found to contain a massless pseudoscalar particle (the Goldstone boson), a scalar particle of mass 2 m and an axialvector particle of mass 2 m - d, d > 0, where m is the mass of the quasiparticles and d a small quantity depending on the number of lattice points (or equivalently the cutoff). The method of summation of chain and ladder diagrams by means of the Fierz formula is treated in some detail. Analogies with the model of Nambu and Jona-Lasinio are pointed out. Finally some remarks on the scattering problem are added
Microwave Absorption Spectra of AlF, GaF, InF, and TIF
Authors: Hoeft J. , Lovas F. J. , Tiemann E. , Törring T.
Published: February 2015

Observation of various rotational transitions of four Group Ilia monofluoride allowed the Dunham coefficients Y01, Y11, Y21 and Y12 to be determined. From the hyperfine structure of the AlF, GaF and InF spectra, the nuclear electric quadrupole coupling constants, e qv Q, and spin-rotation coupling constant, CI, were obtained for several vibrational states, v:

e qv Q(27 Al19F) = -37,75(8) + 0,44(8) (v + 1/2) MHz,

e qv Q(69 Ga19F) = -107,07(8) + 1,09(7) (v + 1/2) MHz,

e qv Q(71 Ga19F) = -67,46(8) + 0,68(7) (v + 1/2) MHz,

e qv Q(115 In19F) = -727,06(20) + 6,64(20) (v + 1/2) MHz.

Stark effect measurements on GaF and InF in the ground vibrational state resulted in the following electric dipole moments:

69Ga 19F: |μ̄| = 2,45 (5) D,

115In 19F: |μ̄| = 3,40 (7) D
Thermoosmose in Flüssigkeiten
Authors: Haase R. , Greiff H. J. de , Buchner H.-J.
Published: February 2015

Neue Messungen am System Cellophan (600) + Wasser im Temperaturbereich zwischen 10 °C und 90 °C werden mitgeteilt und diskutiert. Es handelt sich um die Permeabilität, die Überführungswärme und die thermoosmotische Permeabilität, die für Permeation und Thermoosmose maßgebend sind, sowie um die Temperaturabhängigkeit des Wassergehaltes der Folie bei Quellungsgleichgewicht. Es wird untersucht, ob Cellophanfolien in flüssigem Wasser als Porenmembranen bzw. als Löslichkeitsmembranen anzusehen sind. Besondere Aufmerksamkeit wird der Richtungsumkehr der Thermoosmose bei einer mittleren Temperatur von etwa 56 °C gewidmet
Nuclear Dipolar Relaxation in Pure Solids
Authors: Haeberlen U.
Published: February 2015

Relaxation of the nuclear dipolar energy  is considered. The static part of HD sets up an energy reservoir, and its dynamic part is taken as the predominant cause for the spinlattice relaxation. This situation may be realized in nature in such pure solids in which molecular reorientations are frequent. Relaxation steps in which the total nuclear spin quantum number does not change are treated in detail. They are found to involve always three nuclear spins. The theory is applied to solid benzene in which the molecules are assumed to reorient about their 6fold symmetry axis. Both intra- and intermolecular interactions need to be taken into account. The theoretical results obtained are in close agreement with recent measurements of van Steenwinkel.
Impurity Diffusion in Lithium
Authors: Ott Aadu
Published: February 2015

The diffusion of 115mCd, 203Hg and 72Ga tracers in lithium metal has been studied, using a thin film deposition and sectioning method.

The experimental results can be expressed by the following Arrhenius relations:

These results, which do not agree with any established theory of impurity diffusion in a metallic lattice, are discussed together with data from previous experiments in terms of the systematics of the dependence of the diffusivity on the "ionizability" of an impurity atom in Li, and on the size of the impurity. In this way a qualitative explanation of the different diffusions rates can be obtained. The relatively large and electropositive impurities appear to diffuse mainly via a vacancy mechanism and the small and electronegative ones mainly as interstitials. The distinction substitutional-interstitial is less pronounced for very large impurities, which may also exhibit tendencies to be trapped at lattice defects.
Notizen: Ternary systems of potassium thiocyanate, formate and halides
Authors: Cingolani A. , Gambugiati M. A. , Berchiesi G.
Published: February 2015

By employing a visual method, solid-liquid equilibria were studied for various mixtures in order to draw maps of ternary systems formed with potassium thiocyanate, formate and halides. Within the accessible portion of each system, three crystallization regions and one ternary eutectic were identified. Areas of crystallization regions are considered in their relation to the radius of the halogen ions.
Gleichzeitige Bestimmung von Elektronenkonzentration und Elektronenstoßzahl in einem örtlich langsam veränderlichen Magnetoplasma
Authors: Muschler W.
Published: February 2015

A previous paper 1 is continued and a wave propagation experiment is treated, which seems suitable for simultaneous determination of electron concentration and electron collision frequency in a plasma permeated by a stationary magnetic field. Electron concentration and electron collision frequency are parameters of the Appleton-Hartree-formula, which describes the complex refractive index of the medium penetrated by the wave. On the other hand the refractive index can be ex-pressed by the complex ratio of the electric and magnetic wave components, if the W.K.B, solutions of coupled wave equations are used. These are valid for a (locally) slowly varying medium. - The complex wave polarisation is another characteristic of the magnetoplasma. It is also defined by simple field strength relations and presents itself for application in the experiment. When both refractive index and wave polarisation are determined by amplitude and phase measurements, electron concentration and electron collision frequency can easily be deduced from the complete Appleton-Hartree-formula.
Frequenzmodulation und Kompression ultrakurzer Lichtimpulse
Authors: Laubereau A. , Von Der Linde D.
Published: February 2015

Expressions are given for the phase modulation by the optical Kerr effect and the resulting frequency broadening of an optical pulse with elliptical polarization. The compression method is discussed for a quantitative comparison with experimental investigations. Starting with single pulses of 20 ps duration and 0.4 cm -1 frequency width, generated by a mode-locked laser and an optical switching device, the phase modulation in an external cell containing CS2 produced a frequency broadening of 5 cm-1 typically. A compression factor of 5 is achieved in a system consisting of one optical grating and a reflection prism. Satisfactory agreement between theory and experiment is obtained for the frequency modulation Δω) and the compression length l. Our data suggest that the time dependence of our input pulses is symmetric with wings of higher power than those of a Gaussian pulse.
Vollständige rs -und r0 -Struktur, 14N-Kernquadrupol-HFS und Dipolmoment von Methylthiocyanat aus dem Mikrowellenspektrum
Authors: Dreizler H. , Rudolph H.D. , Schleser H.
Published: February 2015

The microwave rotational spectra of five isotopic species of the molecule methyl thiocyanate, CH3SCN, have been observed in the region between 7 and 33 GHz. From the rotational constants of these and two other species whose spectra were previously known a complete rs-structure of the molecule could be determined which is compared with several r0-structures obtained subject to certain assumptions. The dipole moment components μa and μb could be determined inclusive of relative sign. The 14N quadrupole coupling tensor, complete with the only non-vanishing non-diagonal element χab, could be evaluated from the HFS of the lines and its change upon isotopic substitution.
Notizen: Quenching of Photoluminescence of Solutions and Intermolecular Energy Transfer
Authors: Bojarski C. , Domsta J.
Published: February 2015

The quenching of photoluminescence by foreign ab-sorbing substances may be described by the following, well-known expression, obtained by FÖRSTER as well as by other authors independently 2 > 3 :
Simplified Model for Ionization and Recombination in a Hydrogenic Plasma with Resonance Radiation Trapping
Authors: Mewe R.
Published: February 2015

The rate coefficients for electron collisional-radiative ionization and recombination have been calculated on the basis of a simplified level scheme for hydrogenic ions in a homogeneous and fully contained plasma with self-absorption for (Doppler broadened) Lyman a radiation. The energy distribution of the electrons is assumed to be Maxwellian. Photoionization is neglected. The cal-culation have been done for a range of electron temperature of Z2 to 10 Z2 eV and electron density of 1014 Z7 to 1024 Z7 m-3 , where Z is the charge number of the bare nucleus.
Self-Focusing of Laser Light and Stimulated Scattering Processes in Transparent and Absorbing Liquids: 1. Self-Focusing
Authors: Maier M. , Rahn O. , Wendl G.
Published: February 2015

The spatial and temporal development of self-focusing of light pulses is investigated. The beam diameter in CS2 and molten para-di-chlorobenzene decreases with increasing incident laser power to small values in good agreement with theory. The strong influence of beam divergence, non-linearity of refractive index, and absorption on self-focusing action is found to agree well with numerical calculations. It is shown that both backward stimulated Brillouin and Raman scattering terminate the self-focusing process.
Quantenmechanik und Objektivierbarkeit/ Quantum Mechanics and Objective Reality
Authors: Baumann K.
Published: February 2015

Quantum Mechanics and Objective Reality A Schrödinger function (or a density matrix) can he ascribed only to an object whose isolation time is larger than its time of revolution. This condition can never be satisfied for macroscopic bodies. Consequently, the "cut" between object and observer must not separate a macroscopic body (measuring apparatus) from the rest of the universe. Hence in an analysis of the measuring process, the state vector of the universe must be introduced. An interpretation of this state vector is given which provides an objective description of nature.
Chemically Induced Dynamic Nuclear Polarization
Authors: Lehnig M. , Fischer H.
Published: February 2015

Alkyl radicals are generated by reactions of phenyl radicals in binary mixtures of substituted alkanes. CIDNP-NMR spectra of their reaction products are explained by S - T0-transitions in radical pairs formed in free radical encounters. From comparisons of calculated and observed CIDNP spectra the (g-factor and the proton hyperfine coupling constant of · CHCl2 are determined [g = 2.0080 ± 0.0003, a = (- 17.0 ± 1.0) G]. The inclusion of nuclear relaxation in free radicals in quantitative CIDNP treatments is discussed, and evidence for the radical pair mechanism causing CIDNP of phenyl derivatives during dibenzoylperoxide decompositions is presented.
Lack of Evidence for Shell Effects in the (n,p) and (n,α) Reaction Cross Sections at 14 MeV Neutron Energy
Authors: Qaim S.M.
Published: February 2015

The systematics of cross sections for (n,p) and (n,a) re-actions induced by 14 - 15 MeV neutrons have been reinvesti-gated. No clear evidence for the existence of any proton shell effects in these two reactions was found.

The existence of shell effects in nuclear reactions induced by 14 - 15 MeV neutrons has been postulated by several workers1-4 , but the evidence presented has been rather weak. With the availability of more and better experimental data in recent years, a fresh look at this postulate seemed highly desirable. In case of (n,p) and (n,2n) reactions, the claim for the occurence of shell effects has already been recently repudiated5,6 ; but for (n,α) reactions there seems to exist no evidence against the original claims1,2 that the cross section shows a minimum when the atomic number of the re-sidual nucleus is a magic number. The present article describes briefly a reinvestigation of the systematics of the (n,p) and (n,α) reaction cross sections in the light of the latest experimental data. At 14 MeV neutron energy there appears to be no conclusive evidence for any significant proton shell effects in these two re-actions.
Messung des transversalen Relaxationsverhaltens in Mehrlinienspektren der kernmagnetischen Resonanz
Authors: Stempfle W. , Hoffmann E.G.
Published: February 2015

Es wird eine Methode zur gleichzeitigen Bestimmung des transversalen Spin-Relaxationsverhaltens mehrerer, möglicherweise sogar aller Linien eines NMR-Viellinienspektrums angegeben. Der eine Meiboom-Gill-Impulsfolge begleitende Spin-Echo-Interferenzzug wird einer Fourier-Transformation unterzogen, und zur Gewinnung der Echofolge der einzelnen NMR-Signale werden mehrere partielle Rücktransformationen durchgeführt.
Kinetic Theory for Mixtures of Dilute Gases of Linear Rotating Molecules in an External Magnetic Field (Formal Theory)
Authors: Raum H.H. , Köhler W.E.
Published: February 2015

A transport theory is developed for mixtures of dilute gases consisting of linear rotating diamagnetic molecules in an external homogeneous magnetic field. This formalism is adequate for a treatment of the Senftleben-Beenakker effects for gas mixtures. Starting point is the system of linearized Waldmann-Snider equations. A complete scheme of orthogonal expansion tensors in velocity and rotational angular momentum is given, up to tensors of third rank and power. The moment method is applied to solve the coupled system of Waldmann-Snider equations and the resulting system of transport relaxation equations (TRE) is stated up to third rank tensor equations. The local conservation laws - linearized in the deviation from thermal equilibrium - are derivated from the TRE.
Zusammenstellung der Koeffizienten für die Anpassung komplexer Streufaktoren für schnelle Elektronen durch Polynome
Authors: Haase Oachim
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 6 - 92 zu berechnen.
Ein Iterationsverfahren zur Berechnung von Kraftkonstanten aus Grundschwingungsfrequenzen
Authors: Hüttner W.
Published: February 2015

A method for the adjustment of force constants from vibrational frequencies is presented. It re-presents an alternative to the various types of least-squares procedures which are widely used in force constant calculations, and avoids some of the well-known divergence difficulties which may occur in such least-squares iterations. Solving a system of normal equations is replaced by two simpler operations which cannot become ill-conditioned by singularities. The method applies preferably to cases where the number of excess data is small or zero.
Berechnung von mittleren Schwingungsamplituden nach der Methode der charakteristischen Schwingungen von Müller
Authors: Baran Enrique J.
Published: February 2015

It is shown for many molecules and ions that the "Methode der charakteristischen Schwingungen" of Müller is usefull for the calculation of mean amplitudes of vibrations if the vibrations are rather characteristic.
Radiation-Induced Conformation Changes of the Pyrimidine Ring in a Single Crystal of Dihydrothymine
Authors: Herak J. N.
Published: February 2015

Radiation-induced radicals in a single crystal of dihydrothymine were studied with EPR. It was found that the 5-thymyl radical is the dominant radical species at room temperature. The orientation dependence of the hyperfine couplings can only by explained if one assumes that C(5), C(6) and C(7) lie in the plane defined by the rest of the nonhydrogen atoms of the ring. The highly dis-ordered structure of the ring in the undamaged crystal is ordered if a proton bound to C(5) is removed.
Radiales Druckprofil in einem magnetoplasmadynamischen Wasserstoff-Lichtbogen
Authors: Mccann T. E. , Bohn W. L.
Published: February 2015

The calculation of the radial pressure profile of an MPD-arc as a function of the ambient pres-sure and the superimposed magnetic field as has been developed in a previous paper is extended to the 13-moments approximation. The higher moments approximation introduces additional thermomagnetic forces and changes significantly the structure of the velocity-dependant part of the external viscous forces. While the Hall-effect and the mass flow are practically unaffected by the higher approximation, as far as their influence on the radial pressure profile is concerned, the ambipolar diffusion leads to an appreciably smaller pressure increase than the 5-moments theory. Qualitative differences of the two approximations are discussed beyond the scope of pressure profiles via the generalized Ohm's law. Quantitative results for a partially as well as for a fully ionized plasma are shown in diagrams. The importance of thermomagnetic forces (especially the Nernst effect) for MPD-arcs is clearly pointed out.
Thermotransport of solutes in liquid silver *,**
Authors: Bhat B. N. , Swalin R. A.
Published: February 2015

Thermotransport studies have been made for liquid silver which contained trace amounts of gold, antimony and sulfur. Capillaries containing silver and homogeneously distributed solute were sub­jected to a temperature gradient and solute redistribution at the stationary state was determined by sectioning and radiotracer technique. The net heat of transport was obtained from the slope of a plot of the logarithm of solute concentrations versus reciprocal of absolute temperature. The segregation was rather small for Au but pronounced for Sb and S. Values of Q* for Au, Sb and S are 1688 cal/mole, -6768 cal/mole and -29,000 cal/mole respectively. The experimental results are discussed in terms of the various factors which contribute to the heat of transport.
Thermal Diffusion in Mixtures of Alcohols and Aromatic Hydrocarbons
Authors: Belton P. S. , Tyrrell H. J. V.
Published: February 2015

The thermal diffusion factors observed for these systems vary considerably with concentration, and frequently show a change in sign at some concentration. New data on ethanol-toluene mixtures show that the sign and magnitude of the separation of the components in a thermal gradient are also strongly dependent on the mean temperature of the system. These observations, together with earlier ones on similar systems, can be given a semi-quantitative interpretation in terms of a shift in the average degree of association of the alcohol along the temperature gradient.
Anharmonicity in Diffusion * *
Authors: Flynn C. P.
Published: February 2015

It is emphasized that anharmonic effects are important in determining the parameters describing diffusion processes at elevated temperatures in crystals. The relevance of anharmonicity to the reaction rate and the dynamical theories of diffusion, and to models of defect formation and migra­tion, is discussed. A comparison is made between the theoretical results and some collected experi­mental data pertaiining mainly to ionic crystals
On the Dielectric Constant of Zirconia and Lime-zirconia
Authors: Sanesi Manlio , Cremante Giorgio , Pizzini Sergio , Wagner Vittoriano
Published: February 2015

The dielectric constant of monoclinic zirconia and of lime-zirconia (up to a CaO content of 20% mole) has been measured at 25 °C by the powder method. For pure ZrO2 the D.C. is 13.5, while for lime-zirconia a non linear dependence on the CaO content has been observed in the measured range, with a maximum at about 14% mole CaO. The results are discussed, in the light of the authors previous density data for the same systems, in terms of the width of the homo­geneity range of the solid solutions
Investigation of Excited States of Helium Atoms in a Stationary PIG-Discharge
Authors: Drawin H. W. , Klan F. , Ringler H.
Published: February 2015

Spectral line intensities emitted by a quiescent PIG-discharge have been measured and the population densities up to a principal quantum number n = 24 have been derived from them. The experimentally determined population densities have been compared with theoretical ones calculated on the basis of a collisional-radiative model in which one accounts for electron and atom collisions. I t is shown that even in the case of different electron and atom temperatures, Te and Ta, an evaluation of the Boltzmann plot at medium and moderately high quantum numbers always leads to the electron temperature, whereas the Saha-Eggert equation for the same states may yield incorrect electron densities. The theoretical calculations predict an inflection of the slope of the Boltzmann plot from Te to Ta for very highly excited states. For the plasma para­ meters under which the PIG-discharge was operated (ne ≅ 2.5 × 1012 cm-3, Te ≅ 1200°K, n0 ≅ 1.5 × 1015 cm-3, 300°K) the change of the slope should become visible for states having principal quantum numbers n > 18. Due to the large experimental error bars it was not possible to check this behaviour.
Experimental Effects of R. F. Irradiation on N. M. R. Lines in Solids
Authors: Haupt J. , Steenwinkel R. van
Published: February 2015

In this paper measurements about the steady state of both Zeeman and dipolar energies of a spin system submitted to r. f. irradiation are presented. These experiments were performed in order to provide a quantitative check of the existing theories. Two samples are investigated, polycrystalline benzene in which relaxation is caused by molecular motions and a monocrystal of CaF2 + 0.01% Ce+++ impurities. For both samples the regions of extreme narrowing and of large T1Z/T1D ratio are investigated. The results are discussed in terms of Provotorov's and Redfield's theories. While in the extreme narrowing region fairly good agreement is obtained some restriction to the Provotorov theory is observed in the region of long correlation times.
Activation Volume Measurements
Authors: Beyeler Michele , Lazarus David
Published: February 2015

The determination of the activation volume of diffusion is one of the best methods for the in­vestigation of the relaxation of atoms or ions around defects. This paper discusses two experimental techniques for the determination of the activation volume for diffusion, by studying the effect of hydrostatic pressure on tracer diffusion and on ionic conductivity. Such experiments require a very clean hydrostatic pressure environment, accurate temperature control and measurement, and well defined specimen geometry. The difficulties encountered during such experiments are discussed. Results are given for the activation volumes of diffusion in beryllium and in sodium chloride.
Magnetic Behavior of Europium Silicates Using Nuclear Gamma Resonance Spectroscopy
Authors: Kalvius G.M. , Shenoy G.K.
Published: February 2015

The ferromagnetic transition temperature, the quadrupole interaction, the hyperfine magnetic field, and the isomer shift have been measured in Eu2SiO4 and Eu3SiO5 using the 21.6 keV nuclear gamma resonance in 151Eu. The isomer shifts found (-0.6 mm/sec for Eu2SiO4 and +0.1 mm/sec for Eu3SiO5 against EuS) are less negative than the values typical for other ionic Eu2+ compounds. The magnetic hyperfine fields (280 kOe for Eu2SiO4 and 240 kOe for Eu3SiO5) are much lower than the Eu2+ free ion value. A brief qualitative discussion of these hyperfine parameters is given. A rough correlation between the isomer shift and the transition temperature for various divalent Eu compounds is indicated. The effect of trivalent of the silicates is demonstrated.
Mössbauer Isomer Shifts and Hyperfine Splitting of the 145.4 keV γ-rays of 141Pr
Authors: Kapfhammer W.H. , Maurer W. , Wagner F.E. , Kienle P.E.
Published: February 2015

The Mössbauer scattering of the 145.4 keV γ-rays of 141Pr was observed in a number of praseodymium compounds. From the isomer shifts between trivalent and tetravalent fluorine compounds the value Δ/(r2) = + 12 · 10-3 fm2 was derived for the change of the nuclear charge radius. The magnetic moment of the 145.4 keV state, μ7/2= (2.8 ± 0.2) μN, was deduced from the magnetic hyperfine pattern observed with scatterers of antiferromagnetic PrO2 .
Messung kohärenter Streulängen mit Christiansen-Filtern für Neutronenstrahlung
Authors: Koester L. , Knopf K.
Published: February 2015

Measurements of Neutron-Scattering-Amplitudes using the Christiansen-Filter- Technique By means of Christiansen-Filters it is possible to make use of the high accuracy achieved for the scattering amplitudes of liquids also for solids in form of powders. We investigated the scattering law for the small angle scattering of Neutrons by Christiansen-Filters and found a good agreement between theory and experiment. Using powders of several elements we could measure the scattering amplitudes of the elements with an uncertainty within ± 0.2% to ± 1%.

We got for the bound atoms of

Al: a = (3.449±0.009) F; Nb: a = (7.11 ± 0.04 ) F;

Cr: a = (3.532 ± 0.010) F; Te: a= (5.43 ± 0.04 ) F;

Sb: a = (5.641 ± 0.012) F; and Ta: a = (6.91 ± 0.07) F.

Si: a = (4.159±0.006) F;
Bestimmung von (n n'γ)-Querschnitten für 14,4 MeV-Neutronen im Massebereich A = 46 — 88
Authors: Breunlich W. , Stengel G. , Vonach H.
Published: February 2015

Es wurde eine systematische Untersuchung der (n,n'γ) -Querschnitte für 14 MeV-Neutronen an gg-Kernen im Massenbereich A = 46 - 88 durchgeführt und die Querschnitte für die Anregung des ersten 2+-Niveaus für 19 Kerne im genannten Massenbereich wurden gemessen. Die Ergebnisse können durch das statistische Modell der Kernreaktionen befriedigend erklärt werden.
Einfluß von Neutronenbestrahlung bei 4 °K auf den Schermodul von Kupfer, Aluminium und Platin
Authors: Wenzl Helmut , Kerscher Franz , Fischer Veit , Ehrensperger Klaus , Papathanassopoulos Konstantinos
Published: February 2015

The change of the shearmodulus of pure polycrystalline Al, Cu and Pt due to reactor neutron irradiation at 4 °K has been studied. The shearmodulus was determined by measuring the vibrational frequencies of a helical spring in two different modes (between 50 and 300 Hz) together with internal friction and electrical resistance. Large relative decreases of the shearmodulus ΔG/G per molar fraction c of Frenkel defects were found, namely ΔG/Gc - 47, - 39, - 67 for Al, Cu and Pt, respectively. The absolute values are much larger than expected from lattice theory. The effects cannot be explained by a relaxation of the defects.
Representation of Symmetries and Observables in Functional Hilbert Space. I.
Authors: Rieckers A.
Published: February 2015

A representation of symmetry transformations motivated by the functional formulation of quantum field theory is rigorously discussed in a functional Hilbert space. The set of generating functionals is equipped with an inner product by means of the Friedrichs-Shapiro-integral and completed to an Hilbert space. Unitarity, continuity, and reducibility are investigated for the symmetry operations in this space. Also non-unitary transformations are considered.
Electronic Excitation and Thermodynamic Properties of High Temperature Gases
Authors: Capitelli M. , Ficocelli E.
Published: February 2015

Different cut-off criteria of partition functions have been utilized in order to evaluate the con­tribution of electronic excitation to thermodynamic properties of high temperature gases (5000 °K to 35 000 °K, 10-2-10 atm).

It is shown that properties of single species are strongly affected by the cut-off criterion adopted, i. e. the contribution of electronic excitation to these properties is important.

It is also shown that the reported absence of this contribution to total enthalpies and specific heats of plasmas is the result of an almost complete compensation between "reactional" and "frozen" terms which are all dependent on electronic excitation.
Thermodynamic Investigations of Thin Liquid Layers Between Solid Surfaces II. Water Between Entirely Hydroxylated Fused Silica Surfaces
Authors: Peschel G. , Adlfinger K. H.
Published: February 2015

By a special method the disjoining pressure of water caused by a molecular long range orienta­tion between fully hydroxylated and highly polished fused silica surfaces at different temperatures (0-74 °C) and plate distances ≦ 1000 Å was determined. Four marked maxima were found at about 15°, 32°, 45°, and 61 °C for not too small plate distances. At these temperatures many authors have detected anomalies in the temperature dependence of some physical properties of water. This evidence is discussed in regard to our results which particularly imply thermodynamic quantities derived from the aqueous surface zone.