bluuebunny/crossref_metadata_2025 huggingface dataset:
Die Anwendung eines gittergesteuerten Multipliers bei Fluoreszenzuntersuchungen im Nano-und Subnanosekundengebiet
Authors: Fielder O.
Published: February 2015

A gated image-converter was developed for measurements of fast electron (50 keV) excited fluorescence rise-and decay-times. Crystals of pure anthracene, p-terphenyl and p-terphenyl doped with tetracene give simple exponential decays (24 nsec and 3.5 nsec for pure anthracene and p-therphenyl respectively) but the rise has more interpreted as a many stage excitation process.
Spectroscopic Analysis with Calculated Mean Amplitudes for P4O6 and P4O10
Authors: Cyvin S. J. , Cyvin B. N.
Published: February 2015

Normal coordinate analyses are reported for P4O6 and P4O10 . Harmonic force constants are given in terms of precisely defined symmetry coordinates. The force fields are used to calculate mean amplitudes of vibration, which are compared with electron diffraction data, and some discrepancies are discussed. Calculated atomic vibration mean-square amplitudes, which are of interest in crystallographic studies, are also given.
Experimental and Theoretical Study of the “Intrinsic Contribution” to the Heat of Transport
Authors: Crolet J. L.
Published: February 2015

The thermotransport of divalent Sr, Cd and Mn ions in silver chloride and bromide has been investigated experimentally. A model for the intrinsic contribution to the heat of transport is proposed. This model is used to interpret our experiments, together with other experiments reported in the literature, namely the thermoelectric power of pure silver chloride and bromide, and the thermotransport of antimony in silver and copper metals.
Nonlinear Frequency Shift in Acoustoelectric Domains in GaAs
Authors: Wonneberger W. , Schulz M.
Published: February 2015

A Bommel-Dransfeld technique is used to analyse the frequency spectrum in GaAs acousto­ electric domains up to 8 GHz. Parametric frequency conversion is found to be only dominant at the very onset of domain formation. In the strongly nonlinear regime, the amplified noise is mainly concentrated around the shifting frequency of maximum nonlinear gain. The shift of the maximum gain frequency is generally discussed by a theory of nonlinear ultrasound amplification. An evaluation of the measured frequency shifts by this theory leads to the simple relation |x| ≈ 2 y between the domain electric field and the bunching rate.
Anwendung der SCF-MO-P(LCGO)-Methode auf einige Kohlenwasserstoffe
Authors: Preuss H.
Published: February 2015

Nach einer kurzen Einführung wird das SCF-MO-P(LCGO)-Verfahren auf die Verbindungen Methan, Äthan, Propan, Isobutan, Tetramethylmethan und Methyl-Cyclohexan angewendet und gezeigt, daß auf diese Weise qualitative Aussagen über die Elektronenverteilungen erhalten werden können, die sogar zu einer guten Proportionalität bezüglich der exakten Werte führen. Andererseits erlaubt die Analyse der Elektronenverteilungen, „effektive Atomladungszahlen“ einzuführen, deren Verlauf innerhalb eines Moleküls Anhaltspunkte für die Ladungsverteilung liefert.
Thermodynamik heterogener Gasgleichgewichte
Authors: Neumann G.M. , Knatz W.
Published: February 2015

Zur thermodynamischen Berechnung der chemischen Transportreaktionen in den W olfram-Halo­gen - Sauerstoff-Systemen werden auf Grund empirischer Betrachtungen der Bindungsverhältnisse in den Molekülen die freien Bildungsenthalpien ⊿GB
0 der Verbindungen WO2Br2 , WOBr4 , WO2J2 und der noch hypothetischen Verbindungen WO2F2 und WOJ4 für Temperaturen zwischen 500 und 3600 K ermittelt. Ferner werden die Gleichgewichtskonstanten Kp für die Bildung der entsprechen­ den Verbindungen aus den Elementen im Normalzustand berechnet. Die Daten zeigen eine sehr hohe Stabilität der Wolframoxihalogenverbindungen und deuten auf eine wesentliche Beteiligung der Wolframoxihalogenide am Reaktionsgeschehen in den Systemen Wolfram - Halogen - Sauerstoff.
The Elastic Scattering of Low Energy Electrons in Thomas-Fermi Theory
Authors: Tietz T.
Published: February 2015

A detailed study has been made of the elastic scattering of lew-energy electrons in Thomas-Fermi Theory. The analytical expressions which have been obtained for the scattering length a and the total cross section o are illustrated numerically.
Zweiquanten-Prozesse in den ESR-Spektren von Halogenatomen
Authors: Tiedemann P. , Schindler R.N.
Published: February 2015

Die Beobachtung von Zweiquanten-Absorptionsprozessen im optischen Bereich ist durch den Einsatz lichtstarker Laser ermöglicht worden. Erst diese hohen Bestrahlungsstärken erlauben die Untersuchung nichtlinearer Absorptionsvorgänge1. Mehrquantenübergänge zwischen Zeeman-Niveaus dagegen treten in günstigen Fällen bereits bei verhältnismäßig niedrigen Energiedichten auf 2, 3. Eine quantitative Analyse der Einbis Vierquantenübergänge in atomarem Sauerstoff ist in einer vorangegangenen Mitteilung beschrieben worden4. Dieser Beitrag behandelt Zweiquantenübergänge zwischen Zeeman- Niveaus in Halogenatomen.
Precision Measurement of Transition and Level Energies in 233U
Authors: Egidy T. von , Schult O.W.B. , Kallinger W. , Breitig D. , Sharma R.P. , Koch H.R. , Baader H.A.
Published: February 2015

Gamma ray energies in 233U following the decay of 233Pa were measured with the Risö bent crystal spectrometer. These gamma lines were detected during the study of the 232Th(n,y)233Th reaction. Experimental details will be given elsewhere1. The energies were calibrated with the X-ray lines2 and the annihilation line3. The energies of seven transitions between 270 and 420 keV were determined with an accuracy which is up to a factor of 10 better than previous measurements by Albridge, Hollander, Gallagher, and Hamilton4. The transition energies are shown in the level scheme 4, 5 (Fig. 1 ) . A least squares program was used to fit the level energies to the seven transition energies obtained in this experiment and to four transition energies (below 103 keV) measured precisely by Albridge et al. 4. Level energies could be calculated with an accuracy of about 20 eV (Fig. 1).
Photoablösung von Elektronen bei Si- und NH2
-
Authors: Feldmann D.
Published: February 2015

Mit einer bei früheren Messungen1 erprobten Apparatur wurden die Untersuchungen über die Photoablösung von Elektronen bei stabilen negativen Ionen fortgesetzt. Für Photonenenergien zwischen 0,5 eV und 3,5 eV wurden Größe und Energieabhängigkeit des Wirkungsquerschnittes bei Si- und NH2
- bestimmt. Si--Ionen wurden aus SiCl4 mit einer Stromstärke von 10-9 A erzeugt. Bei Si- hat der gemessene Wirkungsquerschnitt (Abb. 1) eine niederenergetische Schwelle bei einer korrigierten Photonenenergie von (0,56 ± 0,04) eV und einen zweiten Anstieg bei etwa 1,3 eV.
The E2/M1 Multipole Mixing Ratios of the 2' +→ 2 + Transitions in 192Pt and 194Pt
Authors: Bashandy E.
Published: February 2015

The multipole mixing of 2'+ → 2+ transitions in 192Pt and 194Pt has been determined by measuring the absolute K-internal conversion coefficients. The experiments are performed by means of an iron - free double focusing electron spectrometer and Ge(Li) detector. The measurements yield the following values of the E2 : Ml mixing ratio δ:

δ(296) in 192Pt = 6.0 ±0.5,

δ(293) in 194Pt=6.24 ± 0.55.

The results are compared with angular correlation measurements.
Zur "Abbildung" komplexer Bildfunktionen in der Elektronenmikroskopie
Authors: Hoppe W.
Published: February 2015

New developments in the image reconstruction procedures for electron microscopy proposed by us are reported here. Reconstruction procedures with visible light for complex functions are described. In one variant of the procedure bright field micrographs for various tilting of the primary beam are combined. It is shown that in this case a further increase in resolution by a factor of 2 and simultaneous improvement in depth of focus are attainable. The depth of focus is at least equivalent to that of a normal instrument working with a wavelength of λ/4. It is shown that zone correction plates can be used in the microscope according to the same principle. The higher resolution improves the discrimination between heavy and light atoms with the aid of anomalous scattering. The discrimination by anomalous scattering is compared with that attainable by elastic-inelastic scattering (in Crewe's Scanning Microscope) at various resolutions. Some preliminary experiments have been done.
Ein Beitrag zu der Erscheinung der Granulation in der Optik / A Contribution to the Phenomenon of Granularity in Optics
Authors: Barlai P.
Published: February 2015

A Contribution to the Phenomenon of Granularity in Optics Described is a new experiment which produces the known phenomenon of granularity of objects in diffuse coherent light, in the same way for certain image formations of objects in diffuse incoherent light.
Die Molekülstruktur des Cyclooctins C8H12
Authors: Haase Joachim , Krebs Adolf
Published: February 2015

Die Molekülstruktur des Cyclooctins wurde mit Hilfe der Methode der Elektronenbeugung an Gasen bestimmt. Dabei ergaben sich die in Tab. 1 zusammengestellten Strukturdaten, die im Zusammenhang mit anderen molekülphysikalischen Untersuchungen am Cyclooctin diskutiert werden.
Instabilitäten in der Emissionsverteilung farbstoffgeschalteter Rubinlaser
Authors: Aussenegg F. , Möckel P.
Published: February 2015

Theoretische Überlegungen zeigen, daß die Emission eines Riesenimpulslasers mit Farbstoff-schalter bei einem kurzen Resonator in einzelne "Filament-Moden" transversal nullter Ordnung zerfallen kann. Dies kommt dadurch zustande, daß die einzelnen Volumenelemente des Farbstoffschalters unabhängig voneinander den Resonator auf hohe Güte schalten können. Bei langen Resonatoren und beim Schalten mit aktiven Schaltern sollte dieser Effekt nicht auftreten. Es werden Experimente an einem Rubinlaser beschrieben, die diese Überlegungen bestätigen. Filament-Moden bedingen lokal hohe Strahlungsintensitäten und können dadurch zur Zerstörung optischer Bauteile im Resonator führen.
Microwave Spectrum, Dipole Moment and Quadrupole Coupling Constants of Orthofluoropyridine
Authors: Sharma S. D. , Doraiswamy S. , Legell H. , Mäder H. , Sutter D.
Published: February 2015

The rotational spectrum of 2-fluoropyridine has been analyzed in the region between 7 - 40 GHz. The rotational constants for the vibrational ground state are: A = 5870.90 MHz, 5 = 2699.96 MHz, C = 1849.26 MHz. The small inertia defect indicates that the nuclear frame is planar. The two components of the electric dipole moment were obtained from Stark effect measurements: μa = 2.80 ± 0.06 D, μb = 1.87 ± 0.05 D. These values agree well with an INDO closed molecular orbital calculation done at T.I.F.R. From the hyperfine splittings of the rotational line the 14N nuclear quadrupole coupling constant are determined. The values are :

Χaa=-0.02±0.05 MHz, Xbb = -2.80±0.05 MHz, Xcc = +2.82±0.05 MHz
Estimating the Alpha-Particles Transmission through a Barrier
Authors: Cârjan N . , Săndulescu A.
Published: February 2015

Among the numerous doubts associated with the estimation of the alpha-decay penetrabilities, two queries have been selected in order to investigate their justification: is the ambiguous determination of a-nucleus potential a real obstacle and is the JWKB an inadequate approximation ?
Thermal Emission of Electrons from Liquid Helium
Authors: Schoepe W . , Rayfield G . W .
Published: February 2015

The free surface of liquid helium acts as an energy barrier for electrons crossing the surface from the liquid into the vapor. The barrier is shown to be induced by the dielectric image-potential acting on the electrons below the liquid vapor interface. The application of an extracting electric field across the surface reduces the barrier and leads to a potential well below the surface which traps the electrons for extended periods of time. The escape into the vapor phase is shown to be dominated by thermal diffusion from the potential well according to Smoluchowski's equation. By measuring the escape rate a barrier height of 43.8 ± 0.7 K has been found. The top of the well lies 25 Å below the liquid vapor interface. Close to the λ-point and at higher temperatures the escape rate deviates from the theory. The relevancy of the present work for previous and further investigations of thermal eelctron emission from liquid helium is discussed.
On the Acceleration of a Superconducting Macroparticle in a Magnetic Travelling Wave Accelerator
Authors: Anderson D. , Claflin S. , Winterberg F.
Published: February 2015

Two models for describing the operation of a magnetic travelling wave accelerator, the transmission line model and the lumped parameter model, are analyzed. For both cases the current distribution and the magnetic field are calculated. It is shown that the transmission line model can be obtained as the limiting case of the lumped parameter model. It is then assumed that a superconducting solenoid with large persistent currents is used as a projectile with a constant magnetic dipole moment. The motion of this projectile is studied in the case of ignorable flux interaction. The conditions for phase and rotational stability are obtained. It is shown that the projectile has a transverse translational instability. A derivation of the flux interaction current wave is included in the Appendix.
Aktivität des AgCl und Austauschstromdichte des Silbers in KAICI4- und LiCl-KCl-Schmelzen
Authors: Schulze K. , Hoff H.
Published: February 2015

The reduction of Ag+-ions (exchange current density io and charge transfer coefficient a) dissolved in an equimolar mixture of KC1-AlCl3 is studied by the double pulse method. By a comparison with the exchange current densities of silver in LiCl-KCl-melts the influence of the different structures of the electrolytes on the charge transfer is investigated. The great difference in the activity coefficient of silverchloride (γAgCl [LiCl-KCl] = 2.2 and γAgCl[KAlCl4] =82.3) is rather determined by the very limited solubility of the Cl--ions in the AlCl4
--sublattice than by the activity of the silver ion.
VUV Radiation by Dissociative Excitation of NH3
Authors: Böse N . , Sroka W.
Published: February 2015

The NH3 molecule is dissociated in a single step process into excited atoms and ions, which emit a radiation in the VUV. We have observed the Ly series and several lines of N I and N II. Only for Ly α we have found a structure in the shape of the excitation function.
Infrarotspektren des Kohlenmonoxids auf reduziertem Nickel-Natrium-X-Zeolith
Authors: Kölbel H. , Ralek M.
Published: February 2015

Die CO-Banden des an reduzierten Nickel-Natrium-X Zeolithen adsorbierten Kohlenmonoxids zeigen eine, im Vergleich zu anderen Nickelträgerkatalysatoren, anomal große Frequenzverschie-bung (200 cm -1) in der Abhängigkeit vom Bedeckungsgrad. Die Resultate werden im Rahmen der Vorstellungen über die Chemisorption des Kohlenmonoxids auf Metallen diskutiert.
Irrflug-Prozesse mit korrelierten Sprungwahrscheinlichkeiten I
Authors: Keller J.U.
Published: February 2015

Random walk processes often can serve as models for statistical processes like Brownian motion, heat conduction, diffusion and polymerisation of atoms and molecules. Using this model one generally assumes the jumps of the random walk particle to form a set of statistically independent events. In fact the jumps of the random walk particle are correlated to each other, so this assumption only holds as an approximation. In this paper a theory of the most simple type of the onedimensional random walk process with correlated jump-probabilities is developed. The results are demonstrated with two simple examples.
Messung der Magnetfelder am Kernort von 152 Sm und 154 Sm im Sm6Mn23 mit Hilfe der Spinpräzessionsmethode / Measurement of the local magnetic field, at the site of Sm in Sm6Mn23 by the spin precession method
Authors: Richter F. W. , Schütt J.
Published: February 2015

The magnetic field at the site of the nuclei 152 Sm and 154 Sm in a ferrimagnetic Sm6Mn23 probe has been measured by means of the perturbed angular correlation method after Coulomb excitation. The temperature dependence of the magnetic field has been investigated and compared with the results of macroscopic experiments. It can be concluded from the present work that the magnetic field Heff(T) at the site of the Sm nuclei is proportional to the macroscopic magnetisation J (T). We obtained a ferrimagnetic Curie Temperature of TC = 438(5) K in good aggreement with macroscopic values and Heff (T=0 K) = 1300(50) kOe.
Methoden zur Bestimmung von Wirkungsquerschnitten für Spinaustausch und Depolarisation indirekt optisch gepumpter Atome
Authors: Assfalg A. , Fricke J. , Haas J. , Lüscher E.
Published: February 2015

Two methods are described to derive cross sections for spin exchange and spin depolarization of an indirectly pumped alkali vapor with zero nuclear spin. Either pulsed or sinusoidally modulated radiofrequency can be used to destroy the polarization of the indirectly pumped (secondary) system, while the intensity of the transmitted pumping light is observed. Cross sections follow from the indirectly produced depolarization of the primary system i. e. from the change in pumping light transmission or from the phase angle between the rf modulation and the intensity oscillations of the transmitted light. The quality of the two methods is tested by deriving cross sections for spin exchange between Cs and Rb and for depolarization of Rb in Argon buffer gas.
Paramagnetische Elektronenresonanz (EPR) des Europiums in Cadmiumfluorid (CdF2: Eu 2+ ), weitere Untersuchungen / Electron Paramagnetic Resonance (EPR) of Europium in Cadmium - Fluoride (CdF2 : Eu2+), Further Details
Authors: Geist D. , Gerstenhauer E. , Rsckebrandt G.
Published: February 2015

This paper describes EPR measurements within the system CdF2 : Eu 2+ between 77 K and 300 K at 9 GHz and 35 GHz for B || [001]. The measurements enable a test of the formerly determined EPR parameters by the strict numerical solution of the eigenvalue problem including the hyper-fine terms. In particular “forbidden” transitions (ΔM = 2) also occur in a strict cubic crystalline field. An interpretation of the superhyperfine structure at 9 GHz and 35 GHz is compatible with the constants T|| = 6.26 MHz and T| = - 6.04 MHz of the interaction with the F ions of the 1 st shell.
Experimental Study of Low Energy e-O2 Collision Processes
Authors: Linder F. , Schmidt H.
Published: February 2015

Elastic scattering, vibrational excitation to v=1, 2, 3, 4 of the electronic ground state, and electronic excitation to the states a1Δ g and b1Σg
+ of O2 have been measured in a crossed beam apparatus for collision energies from nearly 0 eV to 4 eV. Differential and integral cross sections have been determined and calibrated on an absolute scale. From 15 vibrational levels of O2
-, which could be observed as resonances in the cross sections, the spectroscopic constants for the vibrational structure of O2
- have been derived: ωe = 135 meV and ωeχe = 1 meV. The cross sections for vibrational excitation have the order of 10-18 cm2. eV for the larger resonance peaks. Detailed cross sections have been listed in Table 1. The half width of the resonance can be estimated to Γ ≈ 0.5 meV, which corresponds to a lifetime tof 10-12 sec for the O2
- states. The angular dependence of pure resonance scattering is rather flat and not in accordance with the simplest theoretical model. An analysis of the angular dependence and of the rotational structure of the resonance in a somewhat extended model have been performed. - No electronically excited O2
-states could be detected in the energy range up to 3 eV.
Der Zeemann-Effekt im Rotationsspektrum von 2-Fluoropyridin
Authors: Sutter D.
Published: February 2015

The molecular Zeeman effect has been observed in the rotational spectrum of 2-fluoropyridine at magnetic fields close to 25000 G. The measured molecular g-values are gaa = -0.0880 ± 0.0007, gbb = - 0.0405 ±0.0006, gcc = + 0.0233 ±0.0006, and the two linearily independant components of the magnetic susceptibility anisotropy are 2 · χaa - χbb - χcc = 50.5 ± 1.6 and 2 · χbb - χcc - χaa - 53.8 ± 1.1 in units of 10-6 erg/G2 mol). The a-axis is close to the C-F-bond and the c-axis is perpendicular to the plane of the ring. A comparison of the gas-phase out-of-plane minus the average in-plane values for the susceptibilities of 2-fluoropyridine, pyridine, and fluorobenzene with the corresponding value for benzene in crystalline phase leads to the conclusion that the susceptibilities may change in the order of 10% when going from solid or liquid phase to the gasphase. A short description of the microwave-Zeeman spectrograph built at Kiel University is given. In the theoretical section expressions for the g-values and susceptibilities are derived which are more complete then those used up to now.
Über CdTe-Schichten und -Solarzellen
Authors: Kasse H. , Schneider G.
Published: February 2015

CdTe-Schichten wurden auf verschiedene Weise hergestellt und elektrische und photoelektrische Eigenschaften untersucht. Durch Verdampfen der Verbindung hergestellte Schichten zeigten den Hochvolt-Photovolt-Effekt, die höchsten Spannungen traten für In-dotierte Schichten auf. Durch gleichzeitiges Verdampfen der Komponenten Cd und Te (Dreitemperaturverfahren) erhaltene Schichten zeigten diesen Effekt nicht. Die günstigsten Herstellungsparameter wurden ermittelt. Durch gleichzeitiges Verdampfen von In oder Nachbehandlung der Schichten im Cd-Dampf wurden die elektrischen Widerstände durch Donatordotierung herabgesetzt. Gleichzeitige Dotierung mit Cd und In lieferte die niedrigsten Widerstände. Aus auf Molybdän-Substraten durch Komponentenver-dampfung erhaltenen CdTe-Schichten wurden durch Bildung von n-CdTe -p-Cu2Te-Heteroüber-gängen Solarzellen hergestellt. Dabei wurde der Einfluß verschiedener Dotierung mit Cd, In oder Cd + In untersucht.
On Boundary Conditions Method in the Kinetic Theory of Gases
Authors: Loyalka S. K.
Published: February 2015

It is shown that the work of Cercignani and Tironi on Maxwell's boundary conditions method can be improved in a simple and logical way. The technique for improvement is illustrated by a study of the linearized plane Couette flow problem and it is found that the proposed modification yields results that are identical with some highly accurate variational results.
Notizen: Interpretation of the Hopkinson Secondary Maximum in Terms of Parallel Pumping Theory
Authors: Markert H.
Published: February 2015

Some former measurements are reviewed concerning a secondary maximum occurring at the high-temperature side of the usual Hopkinson peak if a dc-magnetic field is superimposed parallel to the ac-field. Since, with regard to single domain particles embedded in a paramagnetic matrix, the measuring signal is proportional to the high-frequency losses, a secondary maximum indicates some kind of resonance phenomenon which obviously fulfills the geometrical conditions of parallel pumping experiments. It is shown that all other aspects of the experimental results also can be explained sufficiently if being interpreted in terms of parallel pumping theory.
Notizen: Determination of Cation Mobilities in Glasses by Direct Measurement of Drift Velocities (Moving Boundary)
Authors: Baucke F. G. K.
Published: February 2015

A method of concentration profile measurement of luminescent ions by ion sputtering has been applied to detect the boundary between alkali ions of glass wafers, which were contacted anodically by acid solution, and succeeding hydrogen ions after the application of an electric field. The transport number of lithium ions was found to be unity. Mobilities at 25 and 50 °C agree with data obtained from conductivity measurements. From the conductivity change during transport the mobility of succeeding hydrogen ions is also evaluated.
Die Struktur von Elektroreflexionsspektren dotierter Halbleiter / Electroreflectance Spectra in Doped Semiconductors
Authors: Gobrecht H. , Thull R. , Baurschmidt P.
Published: February 2015

Differences in the reflectance spectra of n- and p-doped Ge at the fundamental edge are interpreted in terms of the spatial field-dependence. These changes in the dielectric constants are achieved by a numerical solution of the Poisson equation and a calculation by the Franz-Keldyshtheory. Considering the inhomogeneous perturbation as a multilayer thin film problem the resulting reflectance was found by a recursion relation. Calculations were carried out for several dopings showing the existence of an optimal relation between the doping and the surface field. The ratio of field penetration to wavelength of the incident light accounts for the difference in optical behaviour. These results may well be understood by means of an exponential optical profile replacing the calculated one
Die Molekülstruktur des Tetracyanmethans
Authors: Oberhammer Heinz
Published: February 2015

Die Molekülstruktur des Tetracyanmethans in der Gasphase wurde mit Hilfe der Elektronen beugung bestimmt. Für die Bindungsabstände ergaben sich folgende Werte:

rC - C = 1,484 ± 0,005 Å und rC - N = 1,161 ± 0,003 Å.

Außerdem wurden die Bastansen-Morino-Shrinkage-Effekte für die ungebundenen interatomaren Abstände experimentell ermittelt
Absorption Spectra of Pure and Activated β-Zinc Thiocyanate
Authors: Kynev K. , Gotchev D.
Published: February 2015

The absorption spectra of the pure and lead activated β-modification of Zn (SCN)2 were investigated. For the width of the forbidden band, 4.7 eV as minimal value is obtained. From the experimental data the conclusion is drawn that strongly localized activator states are responsible for the luminescence. The observed absorption bands can be connected with electron transitions to the 3P1,
3P2 and 1P1 term components of the lead ion
The particle moves on a doughnut Nuclear Charge Radius Differences of 15N -14N and 18O-16O
Authors: Schütz W. , Theissen H. , Schmidt K. H. , Frank H.
Published: February 2015

The relative differences of the rms ground state nuclear charge radii of 15N -14N and 18O -16O have been measured by low energy elastic electron scattering to be (1.3 + 0.7)% and (2.4 + 0.6)%, respectively. Both values are less than those following from an A1/3 dependence
Characteristics of a Cresyl Violet Laser
Authors: Schmidt W. , Appt W. , Wittekindt N.
Published: February 2015

The properties of flashlamp-and laser-pumped cresyl violet lasers emitting between 620 and 710 nm were studied. In mixed cresyl violet-rhodamine 6G solutions, the excitation efficiency was found to be enhanced by more than a factor of two, the major part of the excitation energy being supplied by the rhodamine 6G fluorescence radiation.

Self-modelocking in a 3-component solution, containing cresyl violet, rhodamine 6G and a saturable absorber dye, was observed.
Protonen-Relaxation durch Triplett-Excitonen in Naphthalin-und Anthracen-Kristallen
Authors: Kolb H. , Wolf H. C .
Published: February 2015

The spin lattice relaxation time T1 of protons in naphthalene and anthracene crystals is decreased by the presence of metastable triplet excitons in these crystals. The exciton induced relaxation time T1, Exc is measured at 300 °K and 77 °K and at Larmor frequencies between 0.4 and 44 MHz. From the frequency dependence of T1, Exc the exciton-proton correlation time τc at the two temperatures is determined to 5.5 · 10 -12 sec and 4.1·10 -12 sec (±10%) in anthracene and 2.1·10-11 sec and 1·10 -11 sec in naphthalene, assuming scalar proton-electron interaction and statistical incoherent hopping motion of the excitons. The predictions of a theoretical model for exciton-migration are in satisfying agreement with the experimental results as far as experimental data for the parameters of that model are available.
Molekülstrahl-Resonanz-Messungen von Hyperfeinstruktur, Zeeman-und Stark-Effekt an TlCl-Isotopen in verschiedenen Schwingungszuständen / Molecular Beam Resonance Measurements of Hyperfine Structure, Zeeman- and Stark-Effect of TICl-lsotopes in Different Vibrational States
Authors: Ley R. , Schauer W.
Published: February 2015

Hyperfine structure, Stark effect and Zeeman effect of the TlCl molecule have been measured with a molecular beam apparatus using electric four poles as deflecting fields and a homogeneous electric field parallel to a superimposed magnetic field in the transition region. Electric dipole transitions were induced between the hyperfine structure levels of the first rotational state J = 1 in both strong and weak external field.

The following quantities could be evaluated from the spectra: the electric dipole moment µel and the magnetic rotational dipole moment µJ of the molecule, the nuclear spin-rotational interactions c1 and c2

, the scalar and tensor part of the nuclear dipole-dipole interaction dS and dT, the quadrupole coupling constant e q Q of the Cl nucleus, the anisotropy of the magnetic susceptibility ξ⊥− ξ∥ , the anisotropy of the magnetic shielding of the external magnetic field at the position of both nuclei (σ⊥- σ∥)1 and (σ⊥- σ∥)2, the magnetic moment of the Cl nucleus multiplied by the scalar part of the magnetic shielding tensor µ2 · (1 - σS)2. For the most abundant isotop 205Tl35Cl the vibrational dependence of most of these quantities was measured in the vibrational states v =0, 1, 2, 3. Isotopic effects for 203Tl35Cl, 205Tl37Cl and 203Tl37Cl were investigated in the ground vibrational state. In addition the vibrational dependence of the electric dipole moment was measured for all isotopic species.

It is pointed out that the usual connections between (σ⊥- σ∥)1,2 and c1,2 and between ξ⊥− ξ∥ and µJ do not hold when the excited electronic states of the molecule obey Hund’s coupling case c, which occurs most probably in TlCl.
Die Polarisation der σ-Bindungen im Azulen
Authors: Seydewitz H. , Schmid E.D.
Published: February 2015

On the basis of a simple MO-approach a model to interprete the IR-absorption intensity of the aromatic CH-stretching vibration is developed. Accordingly the gradient of the CH-bond moment is a linear function of the ionicity of the CH-bond.

Eight azulenes, which were deuterated at various specified positions, were synthetisized and out of their IR-spectra the gradients of the CH-bond moment at all positions of azulene could be determined. From these experimental data it is concluded, that in relation to benzene the electrons of the CH-bonds in azulene are displaced towards the C-atom at positions with high and towards the H-atom at positions with low π-electron density.

Such a polarisation of the CH-bonds in azulene is confirmed, although only qualitatively, by the ionicities of the CH-bonds calculated by the CNDO/2-method and is also in accordance with other experimental observations such as bond lengths and angles, C13H-coupling constants, and the frequencies of the CH-stretching vibrations.

It is demonstrated that experiment and calculation fail to correlate quantitatively due to in-adequacies inherent in the CNDO/2-method.
On the Ratio L12/L21 For n = 2 Eigenvalue Problems: An Empirical Constraint For The Calculation of Force Constants (Extended L Matrix Approximation)
Authors: Müller A. , Mohan N. , Heidborn U.
Published: February 2015

The variation of the ratio L12/L21 (where Lij refers to the element of the L matrix) as a function of the mass coupling term T=G12/|G|1/2 has been studied for molecules of the type XY4(Td), XY3(D3h) and XY2C2v) using the exact force field data. In the case of the XY4 and XY3 type molecules, the ratio L12/L21 is nearly independent of the mass coupling and in the case of the XY2 type, it shows a nearly linear dependence on T. The force constants have been evaluated using an empirically determined constraint for L12/L21. The values are generally in good agreement with the exact ones. In all cases except VCl4 the exact interaction term of the F matrix is in agreement with the sign rule of Müller et al.
Thermotransport of Noble Metal Impurities in Lead
Authors: Sullivan George A. , Larsson Sune , Thernquist Per T.
Published: February 2015

Steady-state distributions of Au, Ag and Cu tracers in Pb wafers subjected to temperature gradients have been determined. The effective heats of transport were + 5.8 ± 1.1 for Ag, - 0.5 ± 0.3 for Au, and of the order of + 35 for Cu (all in kcal/mole, positive values denoting the impurity migrating to the cold side of the Pb wafer). No significant temperature dependence of the heats of transport could be detected. The results are difficult to reconcile with existing theories of the intrinsic and electronic contribution to the heat of transport.
The (Tl,Na,Li)NO3, (Tl,Na,Rb)NO3, (Tl,Na,Cs)NO3 Ternary Systems
Authors: Cingolani A . , Berchiesi M. A . , Piantoni G. , Leonesi D.
Published: February 2015

Solid-liquid equilibria were studied by a visual method in order to draw the polythermal pro-jections of the (Tl, Na, Li)NO3, (Tl, Na, Rb)NO3 , and (Tl, Na, Cs)NO3 ternary systems. The seven pertinent binaries are also discussed and data concerning the invariant points and crystallization regions are given.
Quantum Condensation, Thermodynamic Limit, and Dimensionality
Authors: Lüders Gerhart
Published: February 2015

With the help of a convenient version of the method of the quasi-expectation value it is shown that quantum condensation of an interacting boson gas does not occur in finite systems and even not if the thermodynamic limit is performed with respect to one or two space dimensions only.
Liquid-Crystalline Curvature Electricity: The Bending Mode of MBBA
Authors: Schmidt D. , Schadt M. , Helfrich W.
Published: February 2015

Measurements are reported which show that the room-temperature nematic MBBA can be deformed by means of curvature electricity if it is contained in a thin sandwich cell with the electric field parallel and the unique axis normal to the bounding walls. Meyer's coefficient e33 was determined to be 4 · 10-5 dyne1/2 at room temperature; and its sign was found to be positive.
Reaktivitätsabschätzungen an substituierten Phenolen mit Hilfe semiempirischer MO-Methoden / Estimations of Reactivity on Substituted Phenols by Semiempirical MO-methods
Authors: Sterk H. , Hopels W.
Published: February 2015

The electron density distributions for a series of phenol derivatives in the ground state are calculated by HMO, EHT, CNDO, and MINDO/2 methods. The values thus obtained provide an explanation for the point of attack in electrophilic substitution reactions, a feature of particular interest being the displacement of a substituent by the attacking agent. The results of the applied MO-methods are compared and discussed.
Der Einfluß tiefer Temperaturen auf die Strahlenschädigung von organischen Kristallen durch 100 keV-Elektronen / The Influence of Very Low Temperature on the Radiation Damage of Organic Crystals Irradiated by 100 keV-Electrons
Authors: Siegel G.
Published: February 2015

The radiation damage of electron irradiated organic compounds (paraffin, tetracene) was investigated in the temperature range 300 - 4 K. The radiation damage was measured by the decrease of diffraction intensities or the contrast of extinction contours. The damage of the crystals at 4 K required considerable higher electron doses than at 300 K. This result is explained as follows: The total radiation damage proceeds by two steps: 1) By primary radiation damage - excitation of energy levels with subsequent dissociation - which is almost temperature independent, 2) by secondary radiation damage - diffusion of molecular fragments - which decreases strongly with decreasing temperature.
Abtragraten und spezifische Energieverluste von 5,6 keV-Edelgasionen an Kieselglas
Authors: Bach H
Published: February 2015

Sputtering yields and damage depths caused in SiO2 glass and thin SiO2 glass-layers by Ne-, Ar-, and Xe-ions of 5.6 keV are reported for the angles of incidence 0°, 45°, and 65°. Nuclear specific energy losses are derived from the mean damage depths. The results are compared with the theory of Brandt and Laubert predicting proportionality of sputtering yield and nuclear specific energy loss. For Ar- and Xe-ions satisfactory agreement is found.

Comparison of measured sputtering yields with yields calculated from experimental specific energy losses allows for corrections of the mean damage depths as obtained with the luminescence method applied earlier.
Low-Energy Electron Diffraction Amplitudes for a "Bare-Substrate" Model
Authors: McRae E. G.
Published: February 2015

A theory of low-energy electron diffraction (LEED) amplitudes is developed for a model in which the crystal surface is represented by a step-function termination of the bulk crystal potential ("bare-substrate" model). The crystal is considered to be centro-symmetric and it is assumed that either the crystal has a two-fold axis of rotation normal to the surface or the primay beam is normally incident on the surface. The origin of coordinates is taken to lie at a center of symmetry of the substrate crystal. The diffraction amplitude is considered as a function of complex electron energy. For a real potential it is shown to have the following properties:

1. The imaginary part of the amplitude vanishes at each branch point of the amplitude function;

2. There are certain segments of the real-energy axis, called "inactive" segments, throughout which the imaginary part of the amplitude vanishes approximately.

The theoretical results are illustrated by a numerical example. It is suggested that the diffraction amplitude can be represented by a simple expression that has the correct functional form and that satisfies the appropriate dispersion relation. One such expression is proposed and discussed in comparison with exact computational results.
Calculation of Reflected Intensities for Medium and High Energy Electron Diffraction
Authors: Moon A.R.
Published: February 2015

The Bethe theory of electron diffraction is used to calculate reflection electron diffraction intensities for medium and high energy electrons. A generalized Hill's determinant method is used for the numerical calculations instead of the more common but slower matrix-eigenvalue technique. Results of a "systematics" calculation of the specular intensity as a function of incident angle are compared with some experimental values for the Si (111) surface. The application of the Bethe theory to crystals where the surface structure differs from the bulk is also considered.
Berücksichtigung der Gitterperiodizität bei der Elektron-Plasmon-Streuung. I / Consideration of Lattice Periodicity at the Electron Plasmon Scattering. 1.
Authors: Münchmeyer W
Published: February 2015

The scattering of electrons by solid-state plasmons is investigated, the system of valence electrons being treated with Green's function method. The lattice periodicity is taken into account for the wave field of the incident electrons as well as for the plasma oscillations of the valence electrons. Scattering processes which contain a reciprocal-lattice vector in the momentum balance appear in addition to the usual inelastic small-angle scattering. Their influence upon the imaginary part of the complex scattering potential is discussed. In a following paper, the reason for the additional scattering processes will be given in terms of the form of the Fermi surface of the solid.
Reciprocity and Shape Functions in Multiple Scattering Diagrams
Authors: Moodie A. F.
Published: February 2015

The scattering amplitude for fast electrons diffracted from a plate of crystal is analyzed in terms of multiple scattering diagrams. It is shown that to every individual scattering process in an arbitrary orientation there exists a process in the reciprocity configuration equal in amplitude and phase, that is, to every diagram there corresponds a reciprocal diagram.

It is shown that the geometric part of the diagram may be expressed in terms of the divided differences of the kinematic shape transform.
Electron Microscope Image Contrast for Thin Crystal
Authors: Cowley J. M. , Iijima Sumio
Published: February 2015

High resolution electron microscope images showing the detailed distribution of metal atoms within the unit cells of complex oxide structures have been recorded recently and as a first approximation may be interpreted as amplitude-object images if obtained with the degree of defocus corresponding to the "optimum-defocus condition" for the phase-contrast imaging of thin phase objects. Detailed observations of images of Ti2Nb10O29 crystals having thicknesses of the order of 100 Å reveal that the thin phase-object approximation, which assumes that only small phase-shifts are involved, is inadequate to explain some features of the image intensities including the variation of contrast with crystal thickness. A very aproximate treatment of the phase contrast due to defocussing of phase objects having large phase shifts is evolved and shown to give a qualitativity correct account of the observations. The variation of image contrast with tilt away from a principle orientation is discussed. From the symmetry of the image contrast it is deduced that the symmetry of the crystal structure as derived from X-ray diffraction studies can not be correct.
Axisymmetric Plasma Flows in External Magnetic Fields with Hall Effect
Authors: Robert K
Published: February 2015

The present analysis refers to steady, barotropic, and inviscid flows of rarefied gas plasmas, both as free jet and within a cylindrical channel, with superimposed electric current, under the influence of an axisymmetric external magnetic field. The non-dimensionalized equations of magnetogasdynamics are linearized by expanding the unknown functions in double power series in terms of the magnetic force number and the magnetic Reynolds number, both assumed smaller than one. For Hall parameters sufficiently small compared to one and slightly curved magnetic lines of force, closed form solutions for the electric current density, as well as plasma velocity and mass density are derived and discussed. Increases in the axial velocity component are achieved more efficiently by using free jet rather than channel flow.
Untersuchungen an stromstarken Kapillarentladungen. Teil II: Kinematische, elektrische und Druck-Messungen / Investigations on High Current Capillary-Discharges. Part II: Kinematic, Electric and Pressure Measurements
Authors: Ehrich Horst , Kusch Hans Jürgen
Published: February 2015

High-current discharges through "Plexiglas" capillaries are investigated with several methods. The front velocity of the plasma jet is obtained by cinematographic techniques, and the streaming velocity by admixing sodium to the jet plasma. Piezoelectric pressure measurements lead, in agreement with other methods, to values of 120 atm at 10 kamps (2 mm diameter of the capillary) ; special care was taken for the dynamical calibration of the pressure probe. From electrical measurements, the electrical conductivity is obtained and compared with theoretical calculations.
Level-Crossing-Experimente an einigen Heliumzuständen bei Ionenstoßanregung / Level-Crossing-Experiments on some He States excited by Ion Impact
Authors: Buchhaupt Klaus
Published: February 2015

An den Heliumzuständen 33P, 43P, 53P, 33D, 43D, 31D , 41D und 51D wurden Hanle-Effekt-Experimente bei Ionenstoßanregung mit Wasserstoff- bzw. Helium-Ionen durchgeführt.

Die Breiten der Hanle-Effekt-Signale der Ausrichtung wurden in Abhängigkeit vom Heliumdruck in der Stoßkammer gemessen. Aus der Druckabhängigkeit der Signalbreiten konnten die natürlichen Lebensdauern τ0 und die Wirkungsquerschnitte σ(2) für die Zerstörung der Ausrichtung bestimmt werden. Bei Anregung durch Helium-Ionenstoß ergaben sich die Werte

33P: τ0 = 98 ± 4,3 ns, σ(2) = (2,0 ± 0,5) · 10-14 cm2,

43P: τ0 = 137 ± 9,4 ns,

53P: τ0 = 196 ± 56 ns, σ(2) = (5,3 ± 1,1) · 10-14 cm2,

33D: τ0 = 39,0 ± 1,4 ns, σ(2) = (4,6 ± 0,5) · 10-14 cm2,

43D: τ0 = 35,5 ± 1,2 ns, σ(2) = (2,9 ± 0,2) · 10-14 cm2,

31D: τ0 = 15,8 ± 0,1 ns, σ(2) = (2,4 ± 0,3) · 10-14 cm2,

41D: τ0 = 39,2 ± 0,8 ns, σ(2) = (4,8 ± 0,5) · 10-14 cm2,

51D: τ0 = 71,9 ± 1,8 ns, σ(2) = (9,6 ± 1,0) · 10-14 cm2.

Aus der Abhängigkeit der Produkte ν für die Zustände 41D und 51D von der kinetischen Energie der anregenden Ionen wurde auf eine Impulsübertragung bei der Ionenstoßanregung geschlossen.
Sound Propagation in Dilute Polyatomic Gases
Authors: Moraal H. , Mccourt F.
Published: February 2015

Sound propagation in dilute pure gases, both monatomic and polyatomic, has been considered from the point of view of the Waldmann-Snider equation. It is shown that the commonly employed assumption that sound propagation in gases is equivalent to the propagation of plane waves is valid only in the region where collisions restore equilibrium faster than it is perturbed by the sound waves. A systematic truncation procedure for an expansion of the perturbation function in irreducible Cartesian tensors is introduced and then illustrated in solutions for three specific kinds of molecules, helium, nitrogen and rough spheres. The agreement between theory and experiment is rather good for sound absorption in the region where the ratio of the collision and sound frequencies is greater than 1.5. The agreement in the case of dispersion is good over the whole measured pressure range. One useful result obtained is to show the polyatomic gas calculations in second approximation have as good agreement with experiment as the calculations for noble gases in third approximation. This can be related to the possession by the polyatomic gas of a bulk viscosity which dominates in sound propagation.
Thermal Properties of Alcaline-Earth-Oxides / III. Analysis of Anharmonic Effects
Authors: Gmelin E. , Vieira S.
Published: February 2015

Experimental heat capacity data for the alcaline-earth-oxides have been used to analyse by a new method the high temperature thermodynamic properties of these crystals in terms of quasi-harmonic and explicit anharmonic contributions.

The explicit anharmonic contribution ΔC is consistent with theoretical predictions; ΔC is proportional to T in a first order approximation. The factor of anharmonicity A is negative for MgO, A = (-0.4 + 0.4) · 10-5 K-1 , for SrO A= (-2.8±1) · 10-5 K-1 and for BaO A=(-3.9±1) ·10-5 K-1 , but positive for CaO A = (2.3 ± 1.2) · 10-5 K-1.

Comparison with the results of analysis of the anharmonic effects in the alcaline-halides shows that the alcaline-earth-oxides may be treated by the same models valuable for the alcaline-halides. The results suggest that the type of anharmonic forces is determined in the alcaline-halides as well as in the alcaline-earth-oxides primarily by the cation of the salt.
Diffusion von Antimon in Gold
Authors: Herzig Chr. , Heumann Th.
Published: February 2015

Die Diffusion von Antimon in Gold wurde in grobkristallinen Proben bei sehr geringer Fremdatomkonzentration mit der Elektronenstrahlmikrosonde im Temperaturbereich von etwa 620 °C bis 1000 °C gemessen. Für Temperaturen über 730 °C lassen sich die Diffusionskoeffizienten darstellen durch die Arrhenius-Beziehung:

D = (1,14 ± 0,19) · 10-2 exp {-(30,90 ± 0,38 kcal/RT) } [cm2/sec] .

Die Ergebnisse werden diskutiert bezüglich des Modells von LeClaire über die Fremddiffusion in Metallen.
Die Molekülstruktur des 3.3.6.6-Tetramethyl-1-thiacycloheptins (C10H16S) / The Molecular Structure of 3.3.6.6-Tetramethyl-1-Thiacycloheptine
Authors: Haase Joachim , Krebs Adolf
Published: February 2015

Die Molekülstruktur des 3.3.6.6-Tetramethyl-thiacycloheptins wurde mit Hilfe der Methode der Elektronenbeugung an Gasen bestimmt. Die Ergebnisse dieser Untersuchung, die in Tab. 1 zusammengestellt sind, werden im Zusammenhang mit den Ergebnissen der Strukturbestimmung des Cyclooctins diskutiert.
Untersuchungen an stromstarken Kapillarentladungen. Teil III: Spektroskopische Messungen / Investigations on High Current Capillary-Discharges. Part 111: Spectroscopic Measurements
Authors: Ehrich Horst , Kusch Hans Jürgen
Published: February 2015

The spectra of the capillary discharges described in Part I and II were investigated. A survey of the spectral emission was obtained by photographic spectroscopy while high-accuracy measurements of the intensity distribution in the wavelength region of 2100 - 6000 Å were performed using photoelectric techniques. Special care was taken for the current vs. intensity-curve of the photo-multiplier and the transparency of the filters used. According to the high reproducibility of the end-on emission of capillary discharges light sources of this type are very suitable for intensity calibration in the field of μsec-spectroscopy.