bluuebunny/crossref_metadata_2025 huggingface dataset:
EPR-Untersuchung an gelösten Radikalionen nicht-alternierender Kohlenwasserstoffe
Authors: Möbius K. , Plato M.
Published: March 2015

The isotropic hfs splitting constants of the radical ions of 6 nonalternant hydrocarbons have been related to MO calculations of spin and charge densities of the π systems. MO calculations were performed with and without including π electron correlation (HÜCKEL, MCLACHLAN, and AMOS-SNYDER). Also bond length alternation has been considered with the aid of a bond order-bond length relation. It turns out that for non-AH’s the full SCF method of AMOS-SNYDER with annihilation of spin quartet states gives the best description of the π electron distribution. The mean deviation between theoretical and experimental splitting constants is still 35% and much higher than in alternant systems. In the case of the dibiphenylene ethylene cation consideration of steric hindrance results in a significant improvement. For the anion of this molecule an oxidation to fluorenone during electrolytic reduction has been observed.
Numerische Lösung der eindimensionalen Schrödinger-Gleichung für verzweigte π-Elektronensysteme mit einem Digitalrechner
Authors: Stratmann W. , Seelig F. F.
Published: March 2015

In the one-dimensional electron gas model the solutions of a one-dimensional SCHRÖDINGER equation are needed. For this purpose the usual HAMILTONIAN is substituted by its finite-difference-approxi-mation. This yields a set of formulae which enable to find the solutions of the SCHRÖDINGER equation by an iterative method. Special provisions are made for the one-dimensional coordinate, which may have a branched form. A program in FORTRAN II for the calculation of the absorption maxima of organic dyes is shortly described.
Über den Einfluß der Adsorption auf die Feldionisierung organischer Substanzen
Authors: Metzinger H. G. , Beckey H. D.
Published: March 2015

The dependence of neutral particle supply to the emission centres of a field ion emitter on adsorption and surface diffusion is investigated.

An equation is derived relating the field ion current to the adsorption energy of organic adsorbates. It follows from this equation that the ion current increases with increasing adsorption energy.

This was confirmed experimentally by a set of seven heptane isomers where the ion current increases with increasing boiling points.

The ion intensities of a series of n-paraffins as a function of molecular weights are also discussed.
On the Distribution of AgBr Grains in Photographic Plates for Ion Detection in Mass-Spectrometers
Authors: Werner H. W. , Nieuwenhuizen J. M.
Published: March 2015

Investigations have been carried out on the distribution of AgBr-grains in unexposed photographic plates (type Q2, Ilford Ltd.) used for ion detection in mass-spectrometers. Electron micrographs show that a large fraction of the grains protrude about halfway out of the gelatine matrix and that these grains are covered by a very thin gelatine layer on the side facing the ions. The mean projection area of the unexposed grains, the percentage of the plate area covered with unexposed grains, and the emulsion thickness have been determined. The shape of unexposed as well as exposed and developed grains is discussed. A model of the distribution of the AgBr-grains in the emulsion is presented.
Das Mikrowellenrotationsspektrum des GeTe
Authors: Hoeft J. , Nolting H.-P.
Published: March 2015

Im Frequenzbereich 11—20 GHz wurden bei Temperaturen zwischen 570 und 600°C Rotationsübergänge von 19 isotopen Molekeln des GeTe gemessen. Es werden Rotationskonstanten, Kernabstände, Koeffizienten der Potentialfunktionen nach DUNHAM und MORSE und Massenverhältnisse von Germanium- und Tellurisotopen mitgeteilt. Als Mittelwert für den Gleichgewichtsabstand der Kerne ergibt sich

re = (2,340 157 ± 0,000 026) A.
Nuclear Quadrupole Resonance Study of 35Cl in Chloral Hydrate, CCl3CH(OH)2, and Chloral Deuterate, CCl3CH(OD)2
Authors: Biedenkapp Dieter , Weiss Alarich
Published: March 2015

The nuclear quadrupole resonance (NQR) spectra of 35Cl in chloral hydrate and chloral deuterate were investigated in the temperature range between 77°K and 323 °K. Two modifications have been found for each substance. One of the modifications is unstable at room temperature and changes within a few weeks into the stable modification. The NQR spectrum can be explained in terms of crystal field effects.
Über eine Erweiterung der ω-Methode
Authors: Försterling H. D. , Kuhn H.
Published: March 2015

Electron repulsion and spin properties of π-electrons are explicitely considered in Pople's SCF-theory; in the ω-method electron interaction is included in a simple way, but there is no physical justification for this procedure. In this paper we describe an LCAO-method (ωrs-method), in which π-electron repulsion is explicitely included and spin properties are neglected. Bond lengths, dipole moments, ionisation energies are calculated, and an explanation of the Scheibe phenomenon is given.
Neue VB+CI-Berechnungen am LiH-Molekül
Authors: Thorhalsson J.
Published: March 2015

Der Grundzustand des Moleküls wird mit einem aus 13 bzw. 7 Konfigurationen bestehenden Satz berechnet. Die Konfigurationen sind aus Slater-Funktionen der vollen K- und L-Schale beider Atome aufgebaut. Die Abschirmzahlen werden variiert, und die Potentialkurve wird berechnet. Es wird festgestellt, daß, wie zu erwarten ist, ein 2s,z-Hybrid an der Bindung maßgeblich beteiligt ist. Die Potentialkurve wird mit einer Funktion vom Morse-Typ approximiert und daraus die spektroskopischen Daten gewonnen. Die Ergebnisse werden an Hand des Hellmann-Feynman- und des Viral-Theorems diskutiert. Das Dipolmoment wird unter Berücksichtigung der Kernschwingungen berechnet.
Das Mikrowellenrotationsspektrum des SnO
Authors: Törring Thoms
Published: March 2015

The rotational transition J=1 ➝ 2 of 7 natural isotopic species of SnO has been observed at a temperature of about 850°C. The transition frequencies are described in terms of the DUNHAM coefficients Y01, Y11, Y21, and Y02. The internuclear distance re and the dissociation energy D have been calculated from the spectrum.
Ein weiterer Hauptsatz über das Messen als Grundlage der Hilbert-Raumstruktur der Quantenmechanik
Authors: Ludwig Günther
Published: March 2015

In einer früheren Arbeit1 des Verfassers wurden Hauptsätze über das Messen formuliert und diskutiert, die HILBERT-Raum-ähnliche Strukturen zu Folge haben. Das in 1 vorgeschlagene System von Axiomen läßt aber wahrscheinlich noch andere Realisationen als den HILBERT-Raum zu. In dieser Arbeit wird ein weiterer Hauptsatz so formuliert, daß im „endlich dimensionalen Fall“ (siehe Axiom l η endlich aus 1) als irreduzible Lösungen nur noch HILBERT-Räume über dem Körper der reellen oder komplexen Zahlen oder der Quaternionen übrig bleiben. Der formulierte Hauptsatz ist im wesentlichen eine Art modulares Postulat, wie es von vielen an die „Propositions“ gestellt wurde [siehe 2 „loi de couverture“ (siehe Anm. 3), Theorem 8 und Axiom 12].

Man kann aber dieses Postulat als Aussage über Gesamtheiten so formulieren, daß es sich leicht und anschaulich physikalisch interpretieren läßt. Ebenso läßt es sich sofort auf den unendlich dimensionalen Fall übertragen, so daß der Verband der abgeschlossenen Teilräume des HILBERT-Raumes (der bekanntlich nicht modular ist!) alle Axiome erfüllt.
Erweiterte Gravitationstheorie, Machsches Prinzip und rotierende Massen
Authors: Brill Dieter R.
Published: March 2015

The rotation of the local inertial frames induced by a rotating shell of mass is calculated in the framework of P. Jordan’s “extended theory of gravitation”. As a special case, the corresponding results are obtained for Brans and Dicke’s “scalar-tensor” theory. In the weak field approximation the result is the same as the Lense-Thirring effect of General Relativity, except for a factor depending on the coupling constant of the scalar field. The strong field limit in which the inertial frame is completely dragged along by the rotating shell is investigated. In particular it is shown that this limit of perfect dragging occurs in certain cosmological models whenever the density of the rest of the matter in the universe tends to zero. This result is interpreted as a manifestation of Mach’s principle in the extended theory of gravitation.
Global Connectivity by Timelike Geodesics
Authors: Seifert Hans-Jürgen
Published: March 2015

The problem of existence of timelike or null geodetic arcs is examinated. It is shown that some transparent causality conditions are sufficient for the existence of an extremal geodetic arc between every pair of events joined by a timelike curve. In the case of a complete space-time these assumptions are also necessary. Some applications to the existence of global space-sections and the structure of space-times with a Cauchy surface are given.
Über den Einfluß der Temperatur auf den Anisotropiegrad des Fluoreszenzlichtes fester Lösungen
Authors: Kawski A. , Czyż P. , Cieślak B.
Published: March 2015

Die Untersuchungen des Anisotropiegrades (Polarisationsgrades) des Fluoreszenzlichtes von 1,1,4,4-Tetraphenylbutadien [TPB], 4,4′-Diphenylstilben [DPS] und 2- (1-naphthyl)-5-phenyloxasol [α-NPO] in Polymethylmethakrylat [PMAM] bei verschiedenen Temperaturen (von ca. 293°K bis ca. 80°K) wurden mit Hilfe einer sehr empfindlichen photoelektrischen Apparatur durchgeführt. Es wurde beobachtet, daß der Emissionsanisotropiegrad mit Erniedrigung der Temperatur anfangs steil abfällt und ab 263°K ungefähr einen konstanten Wert erreicht. Das Verhalten des Emissionsanisotropiegrades von festen Fluoreszenzlösungen in Abhängigkeit von der Temperatur wurde mit Hilfe des inneren Depolarisationsmechanismus (einer Überlagerung von zwei Absorptionsbanden mit senkrecht zueinander orientierten Oszillatoren) erklärt und durch Messung der Absorptionsspektren bei verschiedenen Temperaturen bestätigt.
Messungen des Thermodiffusionsfaktors und Bestimmung des molekularen Wechselwirkungspotentials von gasförmigem Uranhexafluorid
Authors: Kirch P. , Schütte R.
Published: March 2015

Messungen der Thermodiffusion von gasförmigem Uranhexafluorid in einem Thermodiffusionsrohr aus konzentrischen Nickelrohren zeigen, daß der Thermodiffusionsfaktor α zwischen 328°K und 452°K negativ ist und bei 384°K einen Extremwert von -2,9·10-5 erreicht. Unterhalb 328°K und oberhalb 452°K besitzt α positives Vorzeichen. Die gemessene Temperaturabhängigkeit des Thermodiffusionsfaktors von UF6 kann unter Annahme eines Wechselwirkungsgesetzes vom Typ des modifizierten BUCKiNCHAM-Potentials quantitativ beschrieben werden, wenn für die Potentialparameter die Werte s=14,75 und ε*/k=582°K verwendet werden. Unter Verwendung eines experimentellen Zähigkeitswertes wurde der dritte Potentialparameter rm=5,44 Å bestimmt. Mit dem so festgelegten molekularen Wechselwirkungspotential können die Absolutwerte und die Tcmperaturabhängigkeiten sämtlicher Transportkoeffizienten, sowie des zweiten Virialkoeffizienten in Übereinstimmung mit allen neueren Meßwerten theoretisch beschrieben werden.
Mössbauer-Effekt-Untersuchungen an Eisen(II)-bis(α-Diimin)-Komplexen
Authors: König E. , Hüfner S. , Steichele E. , Madeja K.
Published: March 2015

Fe57 MÖSSBAUER spectra have been obtained on twenty-one iron (II)-bis (α-diimine) complexes. The high-spin compounds differ from the low-spin compounds by significantly higher values of the isomer shift δ and of the quadrupole splitting ΔEQ. A recalibration of the total s-electron density is employed to determine 4s populations between 0.19 and 0.27. The order of decreasing values of δ corresponds to the nephelauxetic series, suggesting considerable back-bonding in the spin-paired configuration. The temperature dependence of ΔEQ is used to estimate values of the axial field splitting Δaxial · Six-coordinated iron (II) compounds having a triplet ground state are characterized by values of δ between 0.30 and 0.40 mm/sec, and ΔEQ between 0.18 and 0.32 mm/sec. A tentative explanation for the small ΔEQ is proposed.
Kernresonanz-Emissionslinien während rascher Radikalreaktionen
Authors: Bargon J. , Fischer H.
Published: March 2015

Previously observed nuclear magnetic resonance emission lines of products of rapid radical reactions are explained by chemically induced dynamic nuclear polarization. This polarization occurs after the production of radicals by the dynamic coupling between radical electrons and protons, and it is transfered to the products by the secondary reaction. A theoretical analysis shows that this concept leads to a correct order of magnitude calculation of the intensity of emission. New experiments are described the results of which support the explanation. It is concluded that chemically induced dynamic nuclear polarization is not restricted to the systems treated so far but may occur in other investigations also.
Blitzlampengepumpte Farbstofflaser
Authors: Schmidt Werner , Schäfer Fritz P.
Published: March 2015

The threshold pumping power required for dye lasers increases with increasing rise time of the pumping pulse. This is shown by experiments and by analog computer calculations based on the assumption that the population of the upper laser level is depleted by transitions into triplet states of the dye molecules.

A special flash lamp with a pulse rise time of 300 ns was used as a pumping light source. Pulse form measurements of spontaneous and laser emission from dye solutions pumped by this flash lamp support the above assumption.
Messung der Absorptionsoszillatorenstärken von OI-Linien im Vakuum-UV-Spektralbereich
Authors: Boldt G. , Labuhn F.
Published: March 2015

The absorption oscillator strengths of the 0I-lines at 1152, 1218, 1302, 1305, and 1306 Å are measured in emission. The light source for this purpose is a wall-stabilized cascade arc burning in an argon plasma into which a small quantity of oxygen is introduced. Normal-intensities are produced by the same source. The evaluation of particle-densities is carried out without assuming constancy of mixture ratio and knowledge of any transition probability.
Mikrowellenspektrum, Struktur und l-Typ-Dublett-Aufspaltung der HCNO (Knallsäure)
Authors: Winnewisser Manfred , Bodenseh Hans Karl
Published: March 2015

The microwave spectra of unstable, gaseous fulminic acid H12C14N16O and five of its isotopically substituted species have been studied in the frequency range from 10 to 46 GHz. The spectrum of molecules in the ground vibrational state established the linearity of the chain HCNO. The following rotational constants B0 for the ground state were obtained:

B0 (H12C14N16O) = 11 469.04 MHz, B0 (H12C14N17O) = 11 151.69 MHz,

B0 (D12C14N16O) = 10 292.51 MHz, B0 (H12C14N18O) = 10 865.34 MHz,

B0 (H13C14N16O) = 11 091.57 MHz, B0 (D13C14N16O) = 10 011.18 MHz.

From these a combined r8- and r0-structure has been evaluated: r(C—H) = (1.027±0.001) A, r(C—N) = (1.161 ± 0.015) A, r(N—O) = (1.207±0.015) A.

The rather large uncertainties in the C—N- and N—O-distances are due to the proximity of the N-atom to the center of gravity.

It appears to be the first time that, in the same molecule, two different ι-type doublets (Δl=0, AJ= + 1) and their corresponding series of /-type doubling transitions (Al =2, ΔJ = 0), arising from the two degenerate bending modes (υ4=1 and v5=1), have been observed.

The analysis of the two ι-type doubling series revealed a marked dependence of the /-type doubling constants q4 and q5 on higher powers of the angular momentum J. This J-dependence was found to be substantially different for the two vibrational modes.

The doubling constants given in MHz are

q4=23.6722 - (0.6139·10-3) J(J+1) + (0.1417·10-6) [J(J+1)]2-(0199·10-10) [J(J+1)]3,

q5=34.6391 - (0.1623·10-3) J(J+1) + (1.00·10-9) [J(J+1)]2.

The molecular dipole moment was determined from Stark-effect measurements on the J=0 → 1 transition in the ground state and found to be (3.06 ± 0.15) Debye. The nuclear quadrupole coupling constants for the 14N- and 170-nuclei can be given as

e q Q (17O) = — (12.31 ± 0.12) MHz and | e q Q (14N) | ≦ 0.3 MHz.
Das toroidale schwachionisierte Magnetoplasma II
Authors: Karger F.
Published: March 2015

A special alternating field method was used to eliminate the influence of the concentration effect (described in Part I1) on the measurements of interest and to increase by more than an order of magnitude the critical magnetic field strength for the onset of the helical instability of the positive column. This made it possible to check in detail the theory — formulated in Parts I and II — of a stable, weakly ionized toroidal magnetoplasma (potential profile, density profile, charge carrier losses).

The theoretically predicted transverse electric field strength leading to the torus drift was observed, while the outward density displacement due to the torus drift did not occur. It was proved that the reason for this was an effect which results from a transverse gradient in the rate of ionization (grad ξ effect) and which causes a substantial reduction of the charge carrier losses. In the decaying plasma with vanishing longitudinal electric field, on the other hand, the outward density displacement was reeorded in accordance with the theory.

The influence of the toroidal curvature on the magnetic field strength at which the helical instability sets in and on the turbulent state of the positive column was also investigated. It was also possible to verify the influence of the grad ξ effect on the helical oscillation.

The grad ξ effect may be important for the early heating phase in projected toroidal fusion machines with neutral gas stabilization.
Waves in Multicomponent Vlasov Plasmas with Anisotropic Pressure
Authors: Verheest Frank G.
Published: March 2015

This is a study of the dispersion formulas for small amplitude waves in a fully ionized N-component plasma, in the presence of a constant external magnetic field. The number of ion species (whether positively or negatively charged) is left general. From a BOLTZMANN-VLASOV equation for each component of the plasma the first three moment equations are taken. The lowtemperature approximation is used to close the set of equations. This set is then solved together with the equations of MAXWELL to obtain a general dispersion relation, a determinant of order 3N. This relation is studied for the principal waves, and various compact formulas are derived. They are shown to include several known results, when applied to plasmas of the usual compositions. Their general form makes them suitable for various physical approximations.
Nicht-thermische Besetzungsdichten im Wasserstoffplasma mit Strahlungsabsorption
Authors: Bohn W.L.
Published: March 2015

Steady-state population densities and electron densities are calculated in a non-equilibrium hydrogen plasma at constant pressure. The ratio of the temperatures of electrons and heavy particles is taken as a parameter. The radiation field of the LYMAN lines is included using a mean absorption coefficient for each transition. The deviations of densities of excited levels and electrons from equilibrium values are very large at low temperatures. The ground state population remains closer to equilibrium until the resonance radiation field vanishes with increasing temperature. Deviations from equilibrium are found to be present even at atmospheric pressure. Detailed results are shown in numerous diagrams for pressures from 0.01 to 1 atmosphere and electron temperatures from 5 × 103 to 4×104°K.
Methode zur Berechnung des Mittleren Inneren Potentials und deren Anwendung auf NaCl, KBr und Cu
Authors: Bühner Hans F. , Steeb Siegfried
Published: March 2015

From recently published analytic approximations to X-Ray scattering factors which were obtained from improved wave functions, the mean inner potential (MIP) was calculated according to the BETHE formula. With sodium chloride, potassium bromide and copper the values 7.33, 8.32 and 18.43 Volts, respectively, were obtained. All these values are smaller than the experimental values of 8.24, 9.05 and 19.00 Volts, respectively, which were published recently 3.

The procedure delivers good results with respect to the comparatively simple method of calculation and it has the advantage of being applicable to all kinds of ions and atoms. Furthermore, a method of calculation is given for the case, that the charge cloud covers a greater region than that of one ion.
Untersuchung der Beschreibungsmöglichkeit des Selen 77 als deformierter Kern
Authors: Engels Walter
Published: March 2015

Some aspects of Selen 77 are discussed in the framework of the NILSSON model. The magnetic moment of the 248 keV state give hint fore the existence of a quadrupole force. The large quadrupole moment and the large COULOMB excitation- and (d,d′) -cross sections of some levels indicate collective features. The strong coupling model explains very well the ratio of the reduced B (E2) transition probability. The NILSSON model predicts the spin and the parity of the ground state and gives a better description of the lifetime of the 248 keV level than the spherical shell model. The magnetic moment of the ground state and the 248 keV state are explained by means of a spinpolarisation. The agreement of several values of the decoupling constant is fairly good. On the whole the description of Se77 by the NILSSON model appears to be comparable to the modest success of this model in some rare earth nuclei.
Ein neues c′1Πg — b1IIu-Bandensystem des C2-Moleküls
Authors: Messerle G. , Krauss L.
Published: March 2015

Homogeneous rotational perturbations (Δ Λ = 0) were found in the DESLANDRES-D’AZAMBUJA bands (c1Πg — b1Πu) for v′ ≧ 3. The rotational analysis showed that the c1Πg state is perturbed by an hitherto unknown c′1Πg state. Vibrational levels of the c′1Πg state were determined from ν = 0 up to ν = 5. Furthermore some additional vibrational levels of the c1Πg state could be identified up to ν = 8.

The detection of the c′1Πg state explains the observed strong vibrational perturbation of the c1Πg state. The mutual position of the two 1Πg potential curves is plotted approximately.
Farbzentren des Eisens als Ursache der Farbe von Amethyst
Authors: lehmann Gerhard
Published: March 2015

Durch Elektronenspinresonanzuntersuchungen wurden drei Zentren dreiwertigen Eisens in Amethyst nachgewiesen: auf Si-Gitterplatz mit einem Alkali- oder Erdalkaliion auf benachbartem Zwischengitterplatz (Si) bzw. mit einem Proton an einem der vier nächsten Sauerstoffatome (S2) und ein völlig andersartiges Zentrum, das auf Grund optischer Absorptionsuntersuchungen als Zwischengitterion (I) gedeutet wird. Die Intensitätsänderungen dieser Zentren beim Bleichen und Verfärben des Amethysts lassen sich verstehen unter der Annahme, daß beim Verfärben S1-Zentren zu vierwertigem Eisen oxydiert und ebenso viele I-Zentren zu zweiwertigem reduziert werden. Dabei entstehen S2-Zentren aus S1 als Nebenprodukt der Bestrahlung:

Eine ESR-Linie des Amethystzentrums wurde gefunden, die mit dieser Deutung in Einklang ist. Die Absorptionsbanden bei 545 und 357 nm werden als Elektronenüberführungsbanden ti(π)→2e und t1(π)3t2 gedeutet. Eine eindeutige Zuordnung der schwächeren Kristallfeldbande bei 950 nm ist dagegen bisher nicht möglich. Für Fe4+ in tetraedrischer Anordnung ist eine Bande in diesem Spektralbereich zu erwarten, andererseits zeigt auch zweiwertiges Eisen in synthetischen Quarzen eine gleiche oder zumindest sehr ähnliche Bande. Ihre Lage erlaubt eine klare Entscheidung darüber, welcher von zwei möglichen Zwischengitterplätzen durch das zweiwertige Eisen und damit wahrscheinlich auch durch die I-Zentren des dreiwertigen besetzt wird.
Dynamische Theorie der Röntgenstrahl-Interferenzen an schwach verzerrten Kristallgittern
Authors: kambe Kyozaburo
Published: March 2015

A geometrical-optical approach to the problem of the propagation of X-rays in weakly deformed crystals is developed in a general form along the lines of the Hamilton-Jakobi theory. It starts from the eikonal equation, which has been derived from Maxwell’s equations in Part I1 and arrives at the equations of Penning and Polder3 and Fermat’s principle by Kato 4. The amplitude equation, which has also been derived in Part I, is interpreted by means of the energy-flow picture, the absorption being taken into account.

Application of the theory to the two-beam case gives an equation of rays, which has a remarkable resemblance to the relativistic equation of motion of charged particles in an electromagnetic field. Representation of the lattice distortion by a displacement vector enables one to obtain equations of rays, phases and amplitudes in a form suited to the practical calculation.
Optical Determination of Thermal Conductivity with a Plane Source Technique
Authors: Gustafsson Silas E. , Halling Nils-Olov , Kjellander Rolf A. E.
Published: March 2015

A recently developed plane source method for non-steady-state measurements of the thermal conductivity and thermal diffusivity of transparent liquids is now being applied to the study of molten salts. In these first measurements sodium nitrate and potassium nitrate have been investigated from their melting points to about 450°C. No temperature dependence of the thermal diffusivity can be established for either of the liquids, whereas the thermal conductivity in both cases increases very slowly with the temperature.

A description of the experimental arrangement is included.
Die chemische Zusammensetzung des Steinmeteoriten St. Severin
Authors: Müller O.
Published: March 2015

The meteorite St. Severin, fallen on June 27, 1966, near St. Severin, Department Charente, France, was analyzed. The analytical scheme is described for major and minor constituents and the results are presented in the conventional form as oxides, metals and iron sulphide. According to the values obtained this stony meteorite seems to belong to the group of amphoterite-chondrites which are a subclass of the olivine-hypersthene chondrites.
Polymorphie bei kristallin-flüssigen Substanzen: Smektische Trimorphie
Authors: Demus D. , Sackmann H. , Kunicke G. , Pelzl G. , Salffner R.
Published: March 2015

Some substances with 3 smectic and in part also 1 nematic modification have been prepared. The relations of miscibility of their liquid crystalline modifications in binary systems have been investigated by means of a hot-stage microscope. By the use of our rule of selective miscibility and the observation of the textures the smectic modifications could be arranged into the groups smectic A, C and B. The so far investigated properties of these liquid crystalline modifications point to structures of the same kind for all modifications of the same group.
Die Polymorphie der kristallin-flüssigen Modifikationen in der homologen Reihe der 4′n-Alkoxy-3′-nitrodiphenyl-4-carbonsäuren1
Authors: Demus D. , Kunicke G. , Neelsen J. , Sackmann H.
Published: March 2015

Some members of the homologous series of the 4′-n-alkoxy-3′-nitrodiphenyl-4-carboxylic acids, which have been already described by Gray, were prepared. Their polymorphism in the smectic state was investigated. The relations of selective miscibility between the liquid crystalline modifications have been explored by the investigation of binary diagrams of state. By the use of the rule of selective miscibility, we can state: In this homologous series nematic and smectic A- and C-modifications occur. The two highest members of the series have a new smectic modification marked with the symbol D.
Photoionisationsuntersuchungen an Atomstrahlen
Authors: Comes F. J. , Elzer A. , Speier F.
Published: March 2015

The crossed beam technique is for the first time used in a mass spectrometric investigation of photoionization products. The photoionization threshold of atomic hydrogen is 911 Å and its photoionization cross section is exactly calculable. This allows the amount of ionization to be calculated, if the intensity of the radiation and the particle density are known. On the other hand, an unknown photon flux can be determined from the measured proton current. With the new technique the absolute photoelectric yield and/or the photoionization cross section of gases can be measured.

The experimental device consists essentially of a UV monochromator, a hydrogen atomic beam, and a mass spectrometer. By the atomic beam technique it is also possible to measure the photoionization cross section of unstable particles such as atomic oxygen and atomic nitrogen.
Klassische Größen und quantenmechanische Operatoren in allgemeinen Koordinaten
Authors: Näpfel H. , Ruder H. , Volz H.
Published: March 2015

A method is given to find, in general coordinates, expressions for dynamical quantities connected with infinitesimal transformations. The classical and the corresponding quantum case are considered. A simple translation rule between the two cases is derived by comparison. The efficiency of the method is demonstrated in the example of angular momenta.
Zur Frage des Diffusionsverhaltens des Kupfers auf der Nickelseite des Systems Kupfer—Nickel
Authors: Hehenkamp Theodor
Published: March 2015

Verschiedene Autoren erhielten bei Messungen des gemeinsamen Diffusionskoeffizienten auf der Nickelseite des Systems Kupfer-Nickel unterschiedliche Ergebnisse. Insbesondere wurde in einigen Fällen unterhalb von etwa 15% Kupfer ein Wiederanstieg des DK beobachtet. Zur Klärung des Sachverhalts wurde die Meßgenauigkeit durch Einschränkung des Konzentrationsbereichs auf 28%, 5% und 1% Kupfer und durch Analyse des Diffusionsprofils mit einer Elektronen-Mikrosonde wesentlich gesteigert. Die Versuche zeigen, daß der DK in diesem Konzentrationsbereich zur Nickelseite hin nicht wieder ansteigt, solange man sich im Bereich der Volumendiffusion befindet. Bei 1000°C kann aber die Korngrenzendiffusion bereits mit ins Spiel kommen, insbesondere, wenn es sich um feinkörnige Proben oder elektrolytisch aufgebrachte Schichten handelt. Eine genauere Analyse von Literaturangaben der Diffusion im System Kupfer-Nickel läßt ebenfalls diesen Schluß zu. Der aus den Versuchen bei Extrapolation auf unendliche Verdünnung erhaltene Fremd-Diffusionskoeffizient für Kupfer in Nickel stimmt mit Literaturwerten gut überein.
Ladungszustände von Lithiumionen in Gasen
Authors: Wendt M. , Hartung J.
Published: March 2015

Beams of Li+ ions with velocities between 4 · 108 cm s–1 and 8 · 108 cm s–1 were brought into charge equilibrium in the gases H2 and air. The fractional amounts of Lio, Li+, Li++ and Li+++ are measured. The neutral particles were detected in a simple way. Extrapolation of our results gives good agreement with data of Allison1 for ion velocities v ≦ 3,5 · 108 cms–1. The equilibrium charge q̅ in hydrogen was found to be smaller than that in air at velocities up to 6 · 108 cm s–1 but larger at higher velocities. For the ratios of the equilibrated beam components with charge 3 and 2 (F300/F200) in H2 and air relations are given which enable an extrapolation of our data for q to higher energies.
Untersuchungen zur Beschleunigung von Plasma mit elektromagnetischen Wanderwellen
Authors: Bieger W. , Gresser H. , Hoenen F. , Läuter R. , Richter F. , Stampa A. , Tuczek H.
Published: March 2015

With regard to the application in plasma wind-tunnels or propulsion devices, the electrodeless generation and acceleration of plasma by an electromagnetic wave travelling along a special transmission line are investigated.

Our first aim was to obtain information on the interaction of the wave with the plasma and to determine the initial parameters for effective operation. In the first experiments the efficiency of the process was not a primary concern. The transmission lines were terminated in matched loads where the whole electromagnetic energy at the output of the circuit, of the order of 100 MW, was dissipated. Such devices can be operated only in a pulsed manner, because it is practically impossible to maintain such high energies for long periods of time. Plasma pulses with a length of about 1 m, densities up to 1014 cm-3 and particle velocities between 5 ×106 cm/sec and 1.2 × 108 cm/sec could be produced. The interaction of wave and plasma could be described in good agreement with a simple model in which we assumed the ions of the plasma to be reflected elastically on a magnetic piston. For the production of longer or continuously streaming beams it appears necessary to go over to a feed-back circuit, where the energy at the output of the line is reinjected at the input by using an appropriate transformer. A high frequency oscillator is used to compensate the energy losses resulting from ohmic effects and from the plasma acceleration. The realization of such a circuit was studied theoretically and experimentally.
Oxide and Hydroxide Activity Determination in Oxide Doped Lithium Fluoride
Authors: Trevisan G. , Pizzini S. , Robert G. , Girardi F. , Sabbioni E.
Published: March 2015

Results of independent measurements of thermodynamic activity (by a mass spectrometric method) and concentration (by neutron activation analysis) of lithium oxide in solid lithium fluoride are discussed. The analytical procedures involved as well as the potential uses of these experimental techniques for investigating fluoride-oxide systems are also described.
Über das Elektronenspektrum von Fluorenon Beobachtung einer durch ein elektrisches Feld induzierten Absorptionsbande
Authors: Liptay W. , Weisenberger H. , Tiemann F. , Eberlein W. , Konopka G.
Published: March 2015

Aus der anisotropen Fluoreszenz und aus elektrooptischen Absorptionsmessungen konnten die Übergangsmomentrichtungen der Absorptionsbanden des Fluorenons eindeutig bestimmt und die Veränderungen des Dipolmoments beim Anregungsprozeß für drei Banden ermittelt werden. Die elektrooptischen Absorptionsmessungen zeigten weiterhin, daß die Übergangsmomente der Banden bei 23 000 cm—1 und bei 39 000 cm-1 nur wenig durch ein elektrisches Feld beeinflußt werden; das Übergangsmoment der Bande bei 31 000 cm-1 nimmt dagegen in einem äußeren elektrischen Feld stark zu.

Nach diesen Ergebnissen war zu erwarten, daß die Intensität der Absorptionsbande bei 31 000 cm-1 stark lösungsmittelabhängig ist, die Wellenzahl des Absorptionsmaximums aber nur um einige 100 cm-1 verschoben wird. Durch entsprechende experimentelle Untersuchungen konnte dies bestätigt werden. Die Absorptionsbande bei 31 000 cm-1 ist im Gaszustand verschwunden, also ist der Übergang im freien Molekül mindestens näherungsweise zufällig verboten. Die in Lösungen beobachtbare Intensität (bis ε > 1300) wird nur durch die Störung des Moleküls durch dessen Reaktionsfeld verursacht; es handelt sich also um eine durch ein elektrisches Feld induzierte Absorptionsbande. Durch die Lösungsmittelabhängigkeit der Lage und der Intensität der Absorptionsbande werden früher veröffentlichte theoretische Untersuchungen bestätigt.

In geeigneten Wasserstoffbrückenassoziaten des Fluorenons, z. B. mit Hexafluorisopropanol, wird die Bande bei 31 000 cm-1 noch stärker rotverschoben und die Intensität weiter erhöht (ε =2640). Die n→π* -Bande bei 23 000 bis 28 000 cm-1 wird dagegen stark blauverschoben und kann nicht mehr beobachtet werden. Dies erlaubt eine getrennte Bestimmung der π →π*Absorptionsbande bei ca. 23 000 cm-1, die im nichtwasserstoffverbrückten Fluorenon von der n →π* -Bande überlagert ist.
Untersuchung der magnetischen Struktur von ErAl2 mit thermischen Neutronen
Authors: Will Georg
Published: March 2015

The magnetic properties of ErAl2 have been investigated by neutron diffraction measurements at 300, 77, and 4.2 °K. ErAl2 is ferromagnetic with an additional weak antiferromagnetic peak of unknown origin. The magnetic moment is 8.8 μʙ per Er3+.
Über die Verschiebung zylindrischer Lichtbögen ohne Materiebewegung
Authors: Raeder Jürgen
Published: March 2015

An electric arc may be displaced by a magnetic field, by a gas flow and also by unsymmetric heating and cooling. This occurs for instance, if a portion of the wall of a wall-stabilized arc is heated. For this case the displacement is investigated theoretically for steady state conditions. Furthermore the deflection is calculated for an explicit dependence of electrical and thermal conductivity upon a space variable. The different possibilities considered in theory are realized experimentally. The measurements are in good agreement with the theoretical results.
Die Bestimmung der Dissoziationsenergie des F2-Moleküls und ein Beitrag zu seinem Bandenspektrum
Authors: Stricker W. , Krauss L.
Published: March 2015

The absorption band spectrum of fluorine has been observed in the extreme vacuum ultraviolet using the Hopfield continuum as light source. The spectrum was photographied by means of a 3 m Hilger normal incidence spectrograph fitted with a differential pumping system. From a rapidly converging v′-progression of bands at 877-857 Å the dissociation energy of the F2-molecule in the groundstate has been established as (1.44 ± 0.07) eV. In connection with the emission band spectrum of F2 in the visible it has been possible to determine the states of the participating transitions in the ultraviolet as well as in the visible region.
Dynamic Nuclear Polarization Experiments on 19F in Solutions and their Interpretation by the “Pulse Model” of Molecular Collisions
Authors: Müller-Warmuth W. , Steenwinkel R. van , Noack F.
Published: March 2015

The dynamic fluorine polarization by the Overhauser effect has been studied at four different magnetic field values and at various temperatures in several fluorocarbon solutions. The importance of intermolecular contact couplings is very sensitively dependent on the chemical environment of the fluorine nuclei. The experimental data are interpreted in terms of the stochastic “pulse model” of molecular collisions derived in a preceding paper. The parameters of the model, such as the relative contribution of scalar couplings, the shape and the time scale of collision pulses and the correlation times of the molecular motion are given explicitly for six fluorocarbon solutions of free radicals.
Kinetic Equations
Authors: Bahr U. , Quaas P. , Voss K.
Published: March 2015

Mit Hilfe informationstheoretischer Argumente wird der Anfangszustand zur Zeit t
Kinetic Equations
Authors: Bahr U. , Quaas P. , Voss K.
Published: March 2015

Die von verschiedenen Autoren bei der Ableitung von kinetischen Gleichungen festgestellten Schwierigkeiten in Form von Säkularitäten und Divergenzen können durch geeignete Partialsummationen überwunden werden. Damit ist die Anwendung der Störungstheorie in der klassischen Statistik gerechtfertigt. Aus dem Auftreten von Divergenzen wurden in der Literatur verschiedene physikalische Schlußfolgerungen (logarithmische Dichteabhängigkeit der Transportkoeffizienten, Ungültigkeit der Bogoljubovschen Synchronisationsannahme) gezogen. Das ist nicht gerechtfertigt, da sich die Schwierigkeiten streng überwinden lassen.
Molecular Constants of GeCl4 and SnCl4 from Coriolis Coupling Constants and an Appraisal of the Accuracy of the Method in Determining Force Fields, Mean Amplitudes and Shrinkage
Authors: Kebabçioglu R. , Müller A. , Peacock C. J. , Lange L.
Published: March 2015

The Coriolis Coupling constants of GeCl4 and SnCl4 are obtained from the contours of the ν4 bands and used to determine the force fields. From consideration of these and that previously reported for SiCl4 it is shown that even relatively inaccurate Coriolis constants can yield better force fields and Bastiansen-Morino shrinkage effects than experimental mean amplitudes of vibration; but that for SnCl4 , because of significant differences between usually valid approximate force fields and the Coriolis constant fixed one, a wrong value of the constant may have been obtained.

It is also shown that the force field obtained from Vol’kenshtein’s theory of absolute Raman intensities is not very good for GeCl4 and wildly inaccurate for SnCl4 .
Über das Abklingen der ersten positiven Gruppe des N2 und der Asundi-Banden des CO
Authors: Hartfuss H. J. , Schmillen A.
Published: March 2015

The lifetimes of certain states in the First Positive System of N2 (B 3Πg → A 3Σu+) and the Asundi-Bands of CO (a′ 3Σ → a 3Π) have been measured as a function of pressure after excitation in a pulsed rf discharge. The fluorescence of the investigated CO-system shows exponential decay in contrast to the First Positive System of N2 that throughout has two decay constants. The pressure dependence of the lifetimes has been investigated in the range of 10-2 to 1 torr. This allows to calculate quenching cross-sections of the excited states.
Laufzeitanalyse eines an einem CO2-Molekularstrahl gestreuten K-Atomstrahls
Authors: Gspann J. , Krieg G.
Published: March 2015

A method is described to determine the velocity dependence of scattering processes from timeof-flight measurements with crossed molecular beams. Scattering of a potassium atomic beam by short pulses of a carbon dioxide molecular beam generates attenuation pulses in the intensity of the potassium beam. The time-of-flight broadening of these attenuation pulses is measured employing signal averaging to improve the signal-to-noise ratio from 1 to 100. The experimental results are in accordance with computed time-of-flight distributions based on the additionally measured velocity distributions and geometries of the two molecular beams, and using the known velocity dependence of the K-CO2 scattering cross section.
Isotopenaustausch-Untersuchungen an Silicat-Ionenaustauschern
Authors: Hoinkis E. , Levi H. W.
Published: March 2015

A method has been developed to measure the rate of rapid heterogeneous ion exchange reactions between powdered solids and an aqueous solution within the temperature range from 100 to 180 °C.

The principle of this method is the following: Both the preheated solid and the preheated aqueous solution are brought into contact by breaking a container. After an exchange period of ≧ 10 sec the process is interrupted within a time intervall of 0.2 sec by splashing cold alkohol ( — 115 °C) into the reaction vessel.

By means of this “temperature-jump”-method the isotopic exchange in Ba-zeolite A has been investigated.

The diffusion process was found to be not uniform at temperatures up to 100 °C just as already had been shown for Cs difussion in Zeolith A. Above 100 °C, however, it appears to become an ideal diffusion process exactly obeying the solution of the diffusion-equation for the relevant case over the entire range of the process.
Zeeman and Dipolar Nuclear Relaxation by Paramagnetic Impurities in CaF2
Authors: Steenwinkel R. Van , Zegers P.
Published: March 2015

The relaxation times of Zeeman and dipolar energies have been measured in a single crystal of CaF2 containing Ce impurities at very low concentration. Measurements have been made at various temperatures between 4.2 °K and 77 °K. It is shown that the Zeeman energy relaxation passes from a rapid spin diffusion to a diffusion limited case when the temperature is increased whilst the dipolar energy relaxation seems to be diffusion limited over the whole temperature range.
On the Field Theoretic Functional Calculus for the Anharmonic Oscillator III
Authors: Schuler W. , Stumpf H.
Published: March 2015

The theory of solution for quantum field functional equations is developped for a suitable testproblem of quantum mechanics. In Sect. 1 the functional formulation of the anharmonic oscillator in its spinorial representation is given, and in Sect. 2 translational equivalent functional equations are discussed. The expansion of the physical state functionals into series of basefunctionals and the symmetrical representation of the functional equations for such an expansion is discussed in Sect. 3. In the following Sect. 4 the special symmetric orthogonal Hermitean functionals are used and the explicit representation is derived. In Sect. 5 the functionals are approximated by expansions with only a finite number of terms and the resulting equations are prepared for integration and in Sect. 6 a necessary condition of stationarity is considered. In Sect. 7 the simplest equation for N=1 is discussed in detail and the lowest eigenvalue is obtained. In the appendices technical details are derived.
Notizen: Excitons in the Energy Loss Spectrum of KBr
Authors: Keil P.
Published: March 2015

Electron energy loss measurements on polycrystalline KBrfilms are reported. Excitonic structure is found to be associated not only with the top valence band but also with deeper bands (K+3p-level). The spin-orbit splitting of this state is resolved.
Gas-Solid Interaction
Authors: Sanesi Manlio , Wagner Vittoriano
Published: March 2015

The heats of adsorption on weakly activated γ-aluminium oxide for a number of linear alkanes (from n-butane to n-nonane) and for 2.2.4-trimethylpentane have been determined by GSC and extrapolated to zero surface coverage.

The dependance of the adsorption energy on the number of carbon atoms is discussed on the basis of the bidimensional gas model: it is shown that the interactions of the adsorbates with the oxidic surface are mainly due to London dispersion forces.
Structures of Liquid Mercury and Dilute Liquid Mercury Alloys
Authors: Halder N. C. , Wagner C. N. J.
Published: March 2015

The structures of liquid Hg and the dilute liquid Hg alloys with 0.5 and 2 atomic percent Cd, and 0.5 and 1 atomic percent Pb have been studied by x-ray diffraction using a theta-theta diffractometer with monochromator in the diffracted beam. The addition of 0.5 or 2 atomic percent Cd into Hg did not produce any detectable change in the interference function I (K), where K=4π (sin Θ)/λ, whereas small additions of Pb seem to reduce the asymmetry of the first peak of 1(K) which is observed in pure Hg. Small additions of Pb also cause a slight shift of the second peak of l (K) to smaller K-values. The present results have been used to offer a possible interpretation of the structure of Hg as observed in the liquid state.
Einfluß von Gitterfehlern auf die dielektrischen Eigenschaften von Seignettesalz
Authors: Labouvie Erich W.
Published: March 2015

It is shown by an etching method joined with microscopical observations that the structure of Rochelle salt crystals is not very much disturbed by dislocations and sudares. The correlation between the distributions of dislocations and sudares is obviously determined by the process of crystal growth. Measurements of the upper Curie-point and the dielectric constant are made in order to reveal some influence of these crystal defects on the dielectric properties.
Die Quantenausbeute der strahlungslosen F – F′-Umwandlung
Authors: Stocker Dietrich
Published: March 2015

The quantum efficiency of the production of F′-centers under absorption of light in the F-band is strongly temperature dependent. This paper considers a non-radiative model for this reaction, in which transitions of the excited F-center electron into a polaron band with 2p-symmetry are calculated. The polaron is treated by the strong coupling method giving the possibility of introducing hydrogen functions for the electronic states. The temperature curve of the quantum efficiency is obtained by means of the Pauli master equation. The effective electron mass, which equals the free electron mass after the adaption of the quantum efficiency to the experimental data, stands as a free parameter in the theory.
Notizen: Zur Frage der Phosphoreszenz von Ferrocen
Authors: Müller-Goldegg A. , Voitländer J.
Published: March 2015

The phosphorescence of ferrocene in glassy solution at 77 °K has been investigated and compared with the results of other authors. There is no evidence that the observed weak phosphorescence can be unequivocally Attributed to ferrocene.
Orientierte Substanzabscheidung auf Einkristalloberflächen
Authors: Harsdorff M.
Published: March 2015

In der vorliegenden Arbeit wird ein Modell der orientierten Substanzabsdieidung zur Diskussion gestellt, bei dessen Ableitung der primäre Keimbildungsprozeß vom nachfolgenden Vorgang der Keimausrichtung im Potentialfeld der Unterlage getrennt betrachtet wird. Die Ergebnisse dieser Überlegung gestatten eine übersichtliche Diskussion des Einflusses von Unterlagetemperatur, Aufdampfrate sowie Kondensations- und Platzwechselenergie auf die Schichtorientierung. Die Form der angegebenen Orientierungsbedingung läßt vermuten, daß bei diskontinuierlicher Bedampfung der Unterlagen die Schichtorientierung, verglichen mit den Ergebnissen bei kontinuierlicher Kondensation, verbessert werden kann.