bluuebunny/crossref_metadata_2025 huggingface dataset:
Ionisationsmechanismus in der Relaxationszone schwach instationärer Stoßwellen in Argon und Krypton / Ionisation Mechanism in the Relaxation Zone oj Weakly Instationary Shock Waves in Argon and Krypton
Authors: Meinhold G. , Demmig F. , Bötticher W.
Published: February 2015

The primary ionisation relaxation up to electron densities of ne = 4·1013 cm-3 is investigated by means of 4 mm - microwave - interferometry. The values of the timedependent gas temperature Ta, and gas density na behind the shock front are calculated using a gasdynamic model which strictly takes into account the instationarity of the flow. From the results it is concluded that neither the familiar two step process dominated by atom collisions nor the assumption of additional excitation processes by electron collisions can fully describe the observed ionisation rates. There is evidence that both the ionisation rates and the electron temperature are influenced by transitions between the first four excited states due to superelastic electron collisions. As a result the electron temperature may even exceed the gas temperature.
Investigation of the Afterglow in Helium-Xenon Mixtures at High Pressures
Authors: Zinko H. , Johansson J.
Published: February 2015

The behaviour of high pressure helium afterglows has been measured by means of conductivity and light intensity decay measurements. The plasma was created in a pulsed discharge of typically 30 μsec length and then investigated by means of time resolved spectroscopy and probing pulse diagnostics under conditions which are of interest for noble gas afterglow MHD generators, i. e. a pressure range of 1-4 atm static pressure, the temperature varying from 600 - 970 °K.

A marked increase in plasma lifetime was found when xenon was seeded with a rate of 10-4 to 10-3 to helium. This effect is ascribed partly to the influence of Penning ionization and partly to the fact, that slowly recombining atomic xenon ions dominate the recombination behaviour at the lower xenon seed rates during the investigated time interval of 150 μsec. The pressure dependent effective recombination coefficient is found to be (0.95 + 1.95 · 10-3 P0) 10-8 cm3 sec-1 for pure helium and (0.2 + 5.1 · 1O-4 P0) 10-8 cm3 sec-1 for a xenon seed rate of 3 · 10-4 (P0 = reduced pressure in Torr).
Linienstärken in der 4-0- und 5-0-Rotationsschwingungsbande von Fluorwasserstoff / Line Strengths in the 4-0- and 5-0-Rotation-Vibration-Bands of Hydrogen Fluoride
Authors: Rimpel G.
Published: February 2015

The strengths of 6 lines in the 4-0- and 5-0-rotation-vibration-bands of hydrogen fluoride have been measured in a multiple reflection cell using a direct measurement method. The absolute values of the rotationless matrix elements of the electric dipole moment have been determined to be

|<4|μ(r)|0>| = (3.48 ± 0.13) · 10-22 esu · cm,

|<5|μ(r)|0>| = (8.79 ± 0.54) · 10-23 esu · cm.
Force Constants and Mean Amplitudes of Vibration of Hexahalo Species of Groups IVA and VIA
Authors: Srivastava B. B. , Dublish A. K. , Pandey A. N.
Published: February 2015

The GVFF constants and mean am plitudes of vibration have been calculated for 21 hexahalo species of group IVA and VIA elements. The influence of the cation on these constants is discussed. It has been found that the chemical bonds in the environment of a light cation are relatively stronger than in that of a heavy cation in case of inorganic cations while the situation is opposite in case of organic cations.
Calculation of Line Broadening Cross Sections for Level Crossing Experiments in Alkali-Rare Gas Systems
Authors: Grosswendt B.
Published: February 2015

Using a simple approximation for the theoretical atomic interaction constants cross section data for level crossing and Hanle-effect line broadening experiments in Rb, Mg+ and Ca+ rare gas systems could be derived. It is shown that in the Rb system the interaction C6R-6 is predominant and that the results are little influenced by dipole-quadrupole and repulsive interactions in the frame work of the Lindholm-Foley-Hindmarsh theory.
Kraftkonstanten, mittlere Schwingungsamplituden, Coriolis-Kopplungskonstanten und thermodynamische Funktionen der Moleküle WOCl4 und WOBr4 / Force Constants, Mean Amplitudes, Coriolis Coupling Constants, Thermodynamic Functions, WOCl4 , WOBr4
Authors: Brockner W. , Hovdan H. , Cyvin S. J.
Published: February 2015

A normal co-ordinate analysis of the molecules W 0Cl4 and WOBr4 has been carried out following W ilson’s FG matrix method. Valence force constants based on known (WOCl4) and estimated (WOBr4) molecular parameters have been evaluated. The results support the assignment of the known Raman spectra of W0Cl4 . Also the mean amplitudes of vibration and the perpendicular amplitude correction coefficients K have been computed for the temperatures T = 0 and T = 298 °K. Furthermore the Coriolis coupling constants of the ζz(EaxEb)- type have been determined. Some thermodynamic functions have also been calculated for an ideal gas state at one atmosphere pressure and different temperatures using the rigid rotor harmonic oscillator approximation.
Notizen: 67Zn NMR Anomalous Solvent Isotope Effect in Aqueous Solutions
Authors: Epperlein B. W. , Krüger H. , Lutz  , Schwenk A.
Published: February 2015

For 67Zn NMR lines of solutions of ZnCl2, ZnBr2, and ZnI2 in H2O and D2O an anomalous solvent isotope effect is reported. In D2O solutions the lines are shifted to higher frequencies. The difference between the shieldings in H2O and D2O is e.g. σ(H2O) - σ(D2O) = (13.1 ±0.7) ppm for a concentration of 0.02 moles zinc bromide per mole solvent.
Energy Levels of 53Mn from the β-Decay of 53Fe
Authors: Canto L. F. , Barros S. de
Published: February 2015

The γ rays following the β-decay of 53Fe were investigated with high resolution detectors. Two unreported weak transitions were detected at the energies 1177 ± 1 keV and 2305 ± 1 keV. Log ft values were determined and spin and parity assignments made. On the basis of the results attained, a new decay scheme was proposed. Comparison with theoretical calculations are made.
Ultra Violet and Visible Spectra of Some Divalent Transition Cupferrone Complexes
Authors: Ela A. H. Abou El , Afifi H. H.
Published: February 2015

The UV and visible absorption spectra of the ammonium salt of cupferrone and manganese, cobalt, nickel, copper and zinc divalent cupferrate complexes are investigated. The absorption bands observed are given and assigned on the basis of ligand field theory. In the UV absorption spectrum of the cupferrone metal complexes a characteristic shift in the maxima and minima appears. The effect of solvent on this shift was investigated.
Die 0,71 μm-Spektralstruktur der Photoleitung von trigonalem Selen
Authors: Keßler F. R. , Grohs P.
Published: February 2015

The photoconductivity spectrum of trigonal selenium shows a relative maximum at 0.71 μm. Measurements in the range from 0.6 μm to 0.8 μm at various quantum fluxes and modulation frequencies (4.2 - 216 Hz) indicate that two different recombination mechanisms, one at shorter and one at longer wavelengths than 0.71 μm, are operative, the former being nonlinear and the latter linear. The absorption and reflection spectra were measured too. At the wavelength of change in the recombination mechanism the depth of penetration of the radiation is about 15 μm. This depth correlates with the mean distance between the potential barriers involved in the photoactivated mobility in selenium.
A Soft X-ray Appearance Potential Spectroscopy Study of the Oxidation of Nickel
Authors: Ertl G. , Wandelt K.
Published: February 2015

Variations of the electronic properties of nickel during the first stages of oxidation were studied by means of the soft x-ray appearance potential spectroscopy (APS). The spectra consist of a superposition of contributions from metallic nickel and from NiO and yield no evidence for a continuous change of the oxidation state of the Ni atoms. The binding energy of the 2p3/2-electrons in metallic nickel was found to be 851 eV and is increased in NiO by 1.4 eV. It is concluded from the shape of the APS peaks that with Ni above the Fermi level 3d- and 4s-bands are superimposed whereas with NiO these are separated in energy.
Die Erniedrigung der Ionisationsenergie des C II-Ions in einem Hochdruckplasma
Authors: Ehrich Horst , Kusch Hans Jürgen
Published: February 2015

The lowering of the ionization potential of singly ionized carbon has been determined from measurements of the high - pressure plasma produced by capillary - discharges in plexiglass. Line intensities of C III 2297 Å and C II 2509/2511 Å as well as the electron density from the profile of Ha were obtained side-on by the use of a rapid-scan method while the temperature of the plasma was derived from simultaneous multi-channel-measurements of the optically thick end-on radiation of the plasma column. Rather good agreement is found with the results of the theoretical approaches based on polarization-effects in plasmas.
Formation Cross Sections of Nucleides Produced from Heavy Elements by High-energy Proton Bombardment
Authors: Gupta B. K. , Das S.
Published: February 2015

Theoretical cross sections for the production of elements from 209Bi and natural copper by high-energy proton bombardment have been calculated.
Intramolecular Force Field of Some Tetrahedral Thio and Seleno Anions
Authors: Sanyal Nitish K. , Ahmad Parvez
Published: February 2015

The orbital valence force field (OVFF) and the Urey- Bradley force field (UBFF) have been employed to evaluate the force constants of thio and seleno anions of VA, VB, VIB and VIIB group atoms of the periodic table. These constants were utilized to examine the relative strength of chemical bonds in isoelectronic sequences. Further, for these anions, the variation of the ratio L12/L21 with the mass coupling term (T = G12 √|G|) has been studied. This appears to be an excellent support to the extended L-matrix approximation **.
Kristallstruktur und Konstitution des Perchlorbenzocyclobutens (β-C8Cl8)
Authors: Haase J. , Widmann P.
Published: February 2015

The crystal structure of perchlorobenzocyclobutene (β-C8Cl8) has been investigated and solved by means of the unusual Patterson projection along the axis of twinning, by which the space group had been determined. As a result of the crystal structure analysis the constitution of the molecule, derived by J. Brandmüller and E. Ziegler from spectroscopic measurements, has been found to be true.
The Thermal-Convective Instability in a Stellar Atmosphere with Rotation and Hall Effects
Authors: Sharma R. C.
Published: February 2015

The problem of thermal-convective instability of a stellar atmosphere is considered to include the effects due to rotation and Hall currents in the presence of a uniform vertical magnetic field The criterion for monotonic instability is found to be unchanged by the presence of rotation and Hall effects.
Die Molekülstruktur des N-Chlorsdiwefeloxiddifluoridimids ClNSOF2 / The Molecular Structure of ClNSOF2
Authors: Oberhammer O. , Glemser O. , Klüver H.
Published: February 2015

The molecular structure of ClNSOF2 was determined by electron diffraction of gases. The following geometric parameters were obtained:

Cl-N=1.715(5), S=N=1.484(7), S=O=1.394(3), S-F=1.548(3) Å, ∢ ClNS=114.7 (8), ∢ FSF=92.6(.8), ∢ NSF=111.8(.9) ∢ NSO=117.4 (3.1) and ∢ OSF=108.6 (.8)°. The results for the mean square amplitudes of vibration are given in the paper and an attempt is made to explain differences in corresponding parameters of some related molecules.
Observation of the Quantum and Classical Size Effects in Thin Antimony Films
Authors: Abou El Ela A. H. , Mahmoud S.
Published: February 2015

The quantum size effect was observed in thin polycrystalline antimony films. The variation of the film resistance with thickness is oscillatory. The oscillation period amounts to ~ 25 Å. The Fermi quasimomentum of the electrons in the direction normal to the film surface was determined. A comparison of the results of the observation of the classical and quantum size effects leads to the conclusion that the electron mean free path in antimony films is not limited by the crystallite dimensions.
Anwendungen von INDO-W ellenfunktionen in der Zeeman-Rotationsspektroskopie / Applications of INDO-Wave-functions in Zeeman-rotationsspectroscopy
Authors: Hamer E. , Engelbrecht L. , Sutter D. H.
Published: February 2015

A method is proposed to obtain ground state expectation values for the sums of the squares of the electron coordinates i.e .

from INDO-wavefunctions. This leads to molecular quadrupole moments which are in close agreement with experimental values from investigations of the rotational Zeeman-effect. In combination with rotational Zeemaneffect data

etc. can be used to predict gas-phase bulk susceptibilities and to determine the sign of the molecular g-tensor.
Versuche zur Spinpolarisation der schwereren Elem ente der Stickstoff-Gruppe durch Spinaustausch mit optisch gepumpten Alkalien: Spinpolarisation von 121Sb durch Spinaustausch mit optisch gepumptem 133Cs / Experiments on spin polarization of the heavier Nitrogen group elements by spin exchange with optically pumped alkali atoms: Spin polarization of 121Sb by spin exchange with optically pumped 133Cs
Authors: Tilgner R. , Lüscher E.
Published: February 2015

The molecules of a Sb-vapour were dissociated by irradiating them with an UV-lamp. The three outer electrons of the atoms were spinpolarized in a He buffer atmosphere by spin exchange with optically pumped Cs. For the 121Sb-isotope the polarization was monitored by inducing rf-transitions between the Zeeman sublevels of the F=4 hyperfine niveau.
Tracer Impurity Diffusion in Liquid Metals: Zn and Cd in Gallium
Authors: Larsson S. J. , Eriksson P.-E.
Published: February 2015

The diffusion coefficients of 65Zn and 115Cd in liquid Ga have been measured between 27° and 455 °C. The temperature dependence of D can be represented by a linear plot or by an Arrhenius representation with D0=2.1·10-4 cm2/s, Q=1.60 kcal/mol for Zn, and D0=2.3·10-4 cm2/s, Q=1.77 kcal/mol for Cd. An extrapolation to lower temperatures for Zn in Ga connects to the measurements by Belskii et al. The present results imply that for impurity diffusion in liquid Ga the effects of solute mass are more significant than valence effects.
Tracer Impurity Diffusion in Liquid Metals: Period 5 Elements in Gallium
Authors: Larsson S. J. , Eriksson P.-E. , Lodding A.
Published: February 2015

The diflusivities of 110Ag and of 121Sn in liquid Ga have been measured and compared with recent data for 115Cd and 114In in Ga. The results can be reasonably well expressed by Arrhenius-type relations D = D0 exp{-Q/RT}, with D0=2.2×10-4cm2/s, @ = 1.68 kcal/mole for Ag, and D0=1.6×10-4, Q = 1.49 for Sn. At temperatures above some 380 ° K the diffusion coefficients of Ag, Cd and In in gallium are practically equal, while that of Sn lies about 10% lower. Even at the lowest temperatures the D-values of the different tracers vary by less than 10% from a mean. The low temperature points appear to fall somewhat below the best straight lines in the D vs T diagram. No obvious dependence on valency is discerned; the only reasonable systematics implied by the behaviour of the four elements of period 5 is the inverse root dependence on tracer mass.
Isotopic Composition of Atmospheric Oxygen During the Geological Past
Authors: Heinzinger K. , Schidlowski M. , Junge C.
Published: February 2015

Ablation products of iron meteorites recovered from Tertiary and Devonian sediments have preserved the 18O/16O ratio of atmospheric oxygen from the respective time periods. While the Tertiary atmosphere was characterized by a rather modern δ18O value (~23.3% o vs. SMOW), the δ-value of the Devonian free oxygen reservoir was markedly lower (~17.3‰) which can be explained in terms of a reduced 18O release by contemporary land photosynthesis.
Bond Length, Polarity, and Electronegativity
Authors: Hooydonk G. van
Published: February 2015

The question of bond shortening in heteronuclear bonds is reconsidered in the light of the results obtained with an ionic approximation to chemical bonding. A definite answer can only be given when the relation between an elements valence-state-ionization energy and -electron affinity is understood. Two empirical bond shortening relations, i. e. those of Schomaker-Stevenson and Huggins, are shown to be incompatible.
Absorptionsspektrum von Si2Hx bei der Pulsradiolyse von Monosilan / Si2Hx detected by the Pulse Radiolyse of Monosilane
Authors: Perner D. , Volz A.
Published: February 2015

A pulse radiolysis study of monosilane resulted in the detection of a species Si2Hx which absorbed in the 270 to 290 nm region. Kinetic measurements have shown that this species is formed in an ion-molecule reaction.
Über die Löschung der Excimeren-Fluoreszenz von 4H-Benzo[def]-carbazol durch Pyridin / Quenching of Excimer Fluorescence of 4H-Benzo[def]- carbazole by Pyridine
Authors: Zander M.
Published: February 2015

The selective quenching of the excimer fluorescence of the title compound (I) by pyridine is due to the formation of a hydrogen bond between I and pyridine.
Nucleon-Nucleon Scattering Calculations in a Pole Regularized Spinor Theory
Authors: Dammeier K.
Published: February 2015

A pole regularized nonlinear spinor theory may be a suitable test object to compare scattering calculations of Stumpf's functional quantum theory with LSZ-results. To apply the LSZ-technique in this theory, a dressing of the occurring massless Green's function is necessary. It is shown which special approximations allow for this dressing. The renormalized nucleon-nucleon coupling constant yields the right order of magnitude for the elastic nucleon cross section.
Interaction of Isotopic Modes with Polaritons
Authors: Nitsch W. , Claus R.
Published: February 2015

Weak phonon modes at 2032,5; 2040; 2046; and 2053cm-1 in K3Cu(CN)4 have been assigned to originate from 13C≡14N and 12C≡15N vibrations. The assignments have been carried out using measurements at He-temperatures and in aqueous solutions. Furthermore calculations have been used concerning the frequency shifts and relative intensities with respect to the 12C≡14N vibrations. The coupling of polariton modes associated with the A1-phonon at 2074 and the E-phonon at 2080 cm-1 with the isotopic modes has been experimentally investigated. A comparison of calculated dispersion branches with the experimental data has shown that the isotopic modes can not simply be treated as fundamentals because the coupling observed is much weaker than expected from the general polariton dispersion theory for first order phonons.
Die Verwendung reiner Gauß-Basis-Funktionen zur Beschreibung der Elektronenbeugung an Gasmolekülen unter Berücksichtigung der chemischen Bindung / The Use of Gauss-Lobe-Functions for Calculating the Electron Diffraction Intensity from Gas Molecules under Consideration of Chemical Bond
Authors: Haberl Armin , Haase Joachim
Published: February 2015

The first Born Expression of elastic and inelastic electron scattering from gas molecules of any svmmetry leads to simple analytic expressions if molecular wavefunctions expanded in Gauss-Lobefunctions (GL's) are used and if the effect of molecular vibration is neglected. The result is given and in the case of H2O theoretical intensities are calculated from two HF-wavefunctions with medium sized GL-basis sets [ (5s, 3p/3s,-) and (5s, 4p/5s,-)] and compared with Konaka's experiment.
The Heats of Adsorption of Some Chlorinated Hydrocarbons on Porous γ-Alumina
Authors: Sanesi Manlio
Published: February 2015

The limiting isosteric heats of adsorption on γ-alumina were determined by gas-solid chromatography in the temperature range 150 -225 °C for the compounds: CCl4 (9.0 kcal/mol), CHCl3 (10.2), CH2Cl2 (9.9), CH3-CCl3 (8.2), CH2Cl-CHCl2, (8.2 and 9.6 according to adsorption position) . The results are discussed with regard to possible orientations of the adsorbed molecules on the solid surface as well as to the interaction of the electric surface field with the adsorbate molecular dipoles.
Notizen: Näherungsforniel für den Koeffizienten der thermischen Ausdehnung von assoziationsfreien flüssigen Nichtelektrolyten / Approximation Formula for the Thermal Expansion of Nonassociated Nonelectrolytic Liquids
Authors: Ulbrich Raimund
Published: February 2015

For the calculation of the thermal expansion of nonassociated liquids in terms of molar volume, mol refraction and the "effective electron numbers" a corrected approximation formula is proposed. The thermal expansion of 26 solvents is calculated. - The usefulness of the "effective electron numbers" for the derivation of numeric data for dispersion force potentials of polyatomic molecules is affirmed once more.
Symmetric Form of Coupling Coefficients for Single and Double Point Groups and the Application of Time-Reversal Symmetry
Authors: König E. , Kremer S.
Published: February 2015

Symmetrized coupling coefficients, the 3-Γ symbols, are investigated for an arbitrary molecular point group G ⊂ SO (3) or d G ⊂ SU(2). The definition employs the 3-j symbols of the full covering group SO (3) [or SU(2)] and the expansion coefficients of the basis functions. 〈j m | j Γ γ a〉 . Considerable simplification is achieved by taking into account time-reversal symmetry in conjunction with the lemma of Racah. It is found that the 3-Γ symbols have the same symmetry properties as the 3-j symbols of SO (3). The definition of 6-Γ symbols is likewise introduced. The treatment covers non-simply reducible groups and complex representations as well. For illustration, 3-Γ symbols of the point group I are calculated and presented.
Mobile and Trapped Triplet States in Single Crystals of Charge Transfer Complexes
Authors: Möhwald H. , Sackmann E.
Published: February 2015

Homogeneously doped crystals of charge transfer (CT-) complexes were grown by incorporating aromatic guest donors in host CT-crystals. The host crystals contained 1,2.4,5-tetracyanobenzene (TCNB) as acceptor and deuterated aromatic electron donors. By using such doped crystals CT complexes in a well defined configuration may be studied. The triplet states of the guest complexes were used as ESR spectroscopic probes in order to determine the molecular arrangement in the host lattice. The zero-field-splitting (ZFS) parameters, D and E, of the triplet energy traps were determined and the degree of electron derealization in the triplet state was calculated from these values. In some cases a very strong guest host interaction (multicomplex formation) was established. A method for the determination of CT-triplet energies is described (accuracy 200 cm-1) . The phosphorescence spectrum of the anthracene-TCNB complex was obtained from the delayed emission spectra of different anthracene doped CT-crystals. The vibronic structure is identical to that of anthracene, while the O-O-band of the complex is blue shifted by 600 cm-1.

It is shown that the undoped anthracene-TCNB crystal exhibits P-type delayed fluorescence and that the triplet exciton diffusion in this crystal is nearly temperature independent. In the undoped biphenyl-TCNB crystal E-type delayed fluorescence originating from the thermal depopulation of the mobile triplet excitons is established. The remarkable differences of the two types of triplet excitons are interpreted in terms of the different polarity in the triplet states of the two CT-crystals.
Notizen: Non-empirical Calculation of Quadrupole Coupling Constants in the Hydrogen Bonded System D(OH2)2
+
Authors: Koller J. , Ažman A.
Published: February 2015

The electric field gradient at the hydrogen bonded deuteron in D(OH2)2
+ is calculated. The results do not indicate relations between the quadrupole coupling constants and the OD or OO interatomic distances.
Notizen: Über einige Radikalreaktionen im H - O - N-System / On some Radical-reactions in the H–O–N-System
Authors: Hack W. , Hoyermann K. , Wagner H. Gg.
Published: February 2015

The reactions of OH and HO2, radicals were studied in an isothermal flow reactor using ESR detection technique.

The rate of the reaction

H + O2 + M → HO2 + M (5)

with M = He was measured at T = 300 K k5 = 5 · 1015 cm6/mol2 sec .

Via quantitative measurement of OH-radical concentration by ESR it was shown that the reaction of HO2 radicals with H-Atoms produces mainly OH-radicals.

The reactions

OH + H2O2 → HO2 + H2O (6)

and

NO + HO2 → NO2 + OH (7)

were studied in the temperature range of 298 ≦ T ≦ 670 K.
Forces on Small Particles in Nonhomogeneous Polyatomic Gases
Authors: Vestner H.
Published: February 2015

Waldmann's work on forces on small particles suspended in a nonhomogeneous monatomic gas is extended to a polyatomic gas of rotating molecules. Under the assumption that the coefficient of diffuse reflection is equal to 1, the force the gas exerts on a particle is calculated from an expansion of the distribution function. In general, this force consists of three contributions which are determined by the flow velocity, the translational heat flux, and the pressure tensor in the gas. The latter force vanishes for spheroidal particles, leaving only the frictional and the thermal force. These two forces are given for prolate and oblate spheroids. In particular, the dependence of the thermal force on the orientation of the particle's axis relative to the temperature gradient is discussed, and a comparison with the hydrodynamic and free molecular results is made.
Massenspektrometrische Untersuchungen an der Plasma-Grenzschicht / Mass Spectrometry at the Plasma Sheath
Authors: Henrich Klaus , Müller Karl Gerhard
Published: February 2015

Mass spectrometric measurements of positive ions emerging from Ar-plasmas at 0.1-0.6 Torr are described. The adaption of the mass spectrometer requires besides the extraction probe an ion optical system, which causes the focussing and bunching of the ion current on the entrance of the time-of-flight mass spectrometer. Systematic measurements of the velocity distributions of the different ion species reveal:

1. The Bohm-criterion is confirmed. In front of the wall the ions are heated in the quasineutral zone and are accelerated in the space charge zone, which here is in the order of magnitude of the ion mean free path.

2. Heating and accelerating increase with growing ion current to the extraction probe.

3. A further increase of the probe current causes collisions in the space charge zone which gives rise to a drop of the transmission of the optical system.

4. The measurement of the current of one ion species as a function of the probe current is a simple experimental proof for collisions of the ions in the space charge zone.
Analyse der Gestaltänderung von Aluminiumpulverpartikeln während eines Naßmahlvorganges / Analysis of Shape Alterations of Aluminium Powder Particles during a Wet-Milling Process
Authors: Wagendristel A. , Tschegg E.
Published: February 2015

Contrary to brittle material, the equilibrium grainsize for ductile powders is often approached as an oscillatory function of time. The following paper investigates this behaviour by means of a geometrical analysis of the powder particles, using wet-milled aluminium powder as an example. For the description of the milling kinetics we have used Hüttig's milling functions which are obtained from a sieve analysis, the measuring of the specific area of a powder monolayer, and the determination of the space-filling.
On the Calculation of Scalar Mesons in Functional Nonlinear Spinor Theory
Authors: Bauhoff W.
Published: February 2015

The formulation of nonlinear spinor theory in functional space is used for the calculation of scalar meson masses. The second order equation used, requires an explicit angular momentum reduction. For illustration, this method is also applied to the first order equation. In second order, we get an integral equation of the Bethe-Salpeter type which is solved in Fredholm approximation.
A Concept of Explaining the Properties of Elementary Particles in Terms of Manifolds
Authors: Ławrynowicz Julian , Wojtczak Leszek
Published: February 2015

The authors propose to explain the magnetic moment of elementary particles by a suitable choice of one pseudo-riemannian manifold - the space of observations - and two general Riemannian manifolds - the spaces of the particle connected with the external electromagnetic and nuclear fields, respectively. By a general Riemannian manifold the authors understand a Riemannian manifold whose associated tensor field is allowed to be degenerate. In this way the mass of a particle as well as its electromagnetic and nuclear properties are determined by means of manifolds and mappings between the corresponding Hilbert spaces. A nuclear reaction is then to be interpreted as a mapping between the corresponding pseudo-riemannian manifolds and the associated general Riemannian manifolds. The proposal, competitive to the quantum field theory, presents a different way of describing the properties of physical objects. At the moment it is difficult to decide whether this proposal will lead to a satisfactory explanation of more physical phenomena than those explained by means of the quantum field theory, since it needs further research.
Das Abklingen der Balmer-Linien des Wasserstoffs nach der dissoziativen Anregung von Benzol und Benzol-D6
Authors: Hartfuss Hans J.
Published: February 2015

The decay-curves of the excited fragments H, D, CH, and CD, produced by the impact of 250 eV-electrons on benzene and benzene-d6 , are measured in a crossed-beam-experiment. The lifetimes of the A2 ⊿-state of CH and CD are determined to be 443 ± 5 ns. Furthermore it is found that the Balmer-lines of hydrogen as well as those of deuterium have a common decay-component, which is 77 ± 3 ns and 145 ± 5 ns in the case of H and D respectively. Because of the strong isotope effect, this behaviour is ascribed to a dissociating state of the benzene-molecule.
Die photochemische Abbaurate des Schwefeldioxids in der unteren Atmosphäre Mitteleuropas
Authors: Penzhorn R.-D. , Filby W. G. , Güsten H.
Published: February 2015

The homogeneous removal rate of sulfur dioxide from the lower atmosphere of Central Europe has been calculated on the basis of the photophysical data of SO2 within its absorption bands (2900 -4000 Å) and the measured monochromatic actinic irradiance (solar quantum flux) in Central Europe. The maximum rate of the sunlight-induced photooxidation during the summer was found to be 0.25% per hour. The results are compared with those obtained from experiments in simulated and real atmospheres.
Absorptions- und Emissionsspektrum von V2+ /V3+ in Beryllen
Authors: Schmetzer K. , Eysel H. H.
Published: February 2015

Absorption and emission spectra of beryls doped with a mixture of less than 0.1% V2+ and V3+ have been measured. The resulting crystal field parameters are:

V2+: Dq= 1500 cm-1 , B = 750 cm-1 , C = 3250 cm-1;

V3+: Dq= 1750 cm-1 , B = 580 cm-1 C = 2480 cm-1.

Within the frequency range of our spectrometers the V3+ is dominating in absorption while V2+ produces the observed emission spectrum by superposition of the 4T2-4A2 fluorescence and 2E, 2T -4A2 phosphorescence bands. We were not able to observe emission of V3+
Berechnung angenäherter Intensitätswerte Raman-aktiver Molekülschwingungen mit Hilfe eines modifizierten CNDO/II-Verfahrens
Authors: Bleckmann P.
Published: February 2015

The line intensities in Raman spectra of molecules are determined by means of a perturbation calculation. For this purpose the vibrating molecule was considered under the conditions of static electric fields causing the perturbation in directions parallel to the axis of a Cartesian co-ordinate system of the molecule. The calculated perturbation terms are inserted into the Hartree-Fock - Operator used in the CNDO/II-theory6. This calculation yields the induced dipole moment as a function of the normal coordinate Q, from which the polarizability change upon Q is obtained.
Heiße Banden im Phosphoreszenzspektrum von Coronen
Authors: Zander M.
Published: February 2015

Two temperature-dependent bands on the short wavelengths side of the phosphorescence spectrum of coronene in a perhydro-coronene matrix are identified as hot bands (from higher vibrational levels of the triplet state T1) by measurement of lifetimes and activation energies.
A Class of Energetically Rigid Gravitational Fields
Authors: Goenner H.
Published: February 2015

In Einstein's theory, the physics of gravitational fields is reflected by the geometry of the curved space-time manifold. One of the methods for a study of the geometrical properties of space-time consists in regarding it, locally, as embedded in a higher-dimensional flat space. In this paper, metrics admitting a 3-parameter group of motion are considered which form a generalization of spherically symmetric gravitational fields. A subclass of such metrics can be embedded into a five- dimensional flat space. It is shown that the second fundamental form governing the embedding can be expressed entirely by the energy-momentum tensor of matter and the cosmological constant. Such gravitational fields are called energetically rigid. As an application gravitating perfect fluids are discussed.
Direkte Bestimmung des absoluten Vorzeichens des Triplett- Nullfeld-Parameters D mit hochauflösender optischer Detektion von ESR / Direct Determination of the Absolute Sign of the Triplet Zero Field Parameter D by High Resolution Optical Detection of ESR
Authors: Schuch H. , Seiff F. , Furrer R. , Möbius K. , Dinse K. P.
Published: February 2015

The electronic triplet state sublevels of aromatic molecules generally have different energies already at zero external magnetic field. This zero field splitting usually is too small to be resolved by a high resolution optical spectrometer, and only a high magnetic field (typically 30 kG) yields enough Zeeman-splitting to allow full resolution. From the Zeeman pattern one can extract the absolute sign of the triplet parameter D, which probes the electronic wavefunction of the triplet state.

Compared with purely optical methods with their inherent lack of resolution, we demonstrate that a double resonance method yields the sign of D even in relatively small magnetic fields due to the improved optical resolution.

This double resonance method is a modification of Optical Detection of ESR (ODMR). Now the sign determination seems to be a routine procedure.
Fourier Transform Nuclear Magnetic Resonance Studies of 67Zn
Authors: Epperlein B. W. , Krüger H. , Lutz O. , Schwenk A.
Published: February 2015

67Zn nuclear magnetic resonance studies of various solutions of diverse zinc salts in H2O and D2O are reported. In the solutions of ZnI2, ZnBr2 and ZnCl2 a remarkable chemical shift to higher frequency is observable, whilst for Zn(ClO4)2, Zn(NO3)2 and ZnSO4 no shift is detectable. The 67Zn shifts in zinc halide solutions depend on the isotopic composition of the solvent. The substitution of hydrogen by deuterium in the solvent yields for the 67Zn line an anomalous solvent isotope effect to higher frequency. Moreover for increasing temperature a linear increase of the shift and a nonlinear decrease of the linewidth for the zinc halide solutions were observed.

The ratio of the Larmor frequencies of 67Zn and 37Cl has been measured in an aqueous zinc perchlorate solution, and a magnetic moment has been calculated for 67Zn. The shielding constant for the hydrated zinc ion has been evaluated:

σ*(hydrated 67Zn++ versus 67Zn atom) = − (6.9 ± 0.1) · 10−4.
Paraelektrische Resonanz und dielektrische Dispersion von Wasser in Beryll-Einkristallen / Paraelectric Resonance and Dielectric Dispersion of Water in Beryl Single Crystals
Authors: Rehm H.-J.
Published: February 2015

Paraelectric resonance spectra of beryl crystals are observed in the X-band region between 5 and 20 kV/cm under the condition that the external electric field F[101̅0]. Additional dielectric measurements show, that the paraelectric centres are the monomeric water molecules in the beryl cavities. For water dipoles in beryl only two orientations of the molecular a-axis relative to the crystal C6-axis are possible, and only those with their a-axis parallel to the C6-axis contribute to the paraelectric resonance effect. The electric moment vector µ of these latter molecules may rotate in the (0001)-crystal plane, i. e. around their own a-axis, and has a value of (1.9 ± 0.2) D. A theoretical description of paraelectric resonance is presented for a simplified model: the electric dipoles have 6 equivalent equilibrium positions along the [101̅0]-directions, tunnel effect and external electric fields remove the site degeneracy and we observe a molecular Stark splitting. We calculate a value of (2.0 ± 0.4) GHz for the zero-field splitting in the one-parameter Hamiltonian model.
Thermomagnetische Effekte von Bi-Sb-Legierungen in quantisierenden Feldern / Thermomagnetic Effects in Bi-Sb-Alloys in Quantizing Fields
Authors: Leuchtenberg L. , Schneider G.
Published: February 2015

Thermomagnetic effects in strong magnetic fields have been investigated in undoped Bi95.5Sb4.5 single crystals. With respect to the high mobility of the charge carriers in Bi-Sb-alloys magnetic fields of a few kGauss have already to be regarded as strong fields. Quantum oscillations were observed in a field region up to 18 kGauss. On the basis of a free electron gas model a theory for the oscillatory behaviour of the thermoelectric power in strong magnetic fields was developed. With aid of this theory the experimental results were explained, and Fermi-energy, cyclotron mass and effective mass tensor were calculated. Different band models (EP, NEP, NENP) were discussed. In the present case the NENP-model shows the best agreement with the experimental results.
An Exponential Function for Repulsive Interaction Energy Term I. Application to Alkali Halides
Authors: Misra K. D. , Dixit V. K. , Sharma M. N.
Published: February 2015

The appropriateness of a suitably modified Varshni-Shukla potential has been tested for a series of alkali halide crystals by determining the numerical values of the potential parameters involved, using Hildebrand’s equation of state and thereby computing a few lattice properties. Comparison between the different sets of theoretical and experimental results infers that the present theoretical values exhibit an improvement over those of other workers, using a similar approach but with different potential energy functions. It is concluded that the modified V -S potential function is a good choice for explaining the behaviour of alkali halide lattices.
Druckabhängigkeit der Relaxationszeit in flüssigem CCl4 / Pressure-dependence of the Relaxation Time in Liquid CCl4
Authors: Sedlacek M.
Published: February 2015

The vibrational relaxation time in liquid carbontetrachloride (at 25 °C) has been investigated by Brillouin scattering for pressures ranging up to 1250 bars. From the relation between the liquid density (as a function of pressure) and the relaxation time the diameter of the CCl4-molecule has been calculated. It was found to be 5.31 ± 0.05 Å.
Molecular Reorientations in Liquid and Solid Cyclohexane
Authors: Schulz J.
Published: February 2015

Going out from the recorded line shapes, the true profiles of the vibrational band ν22(Eg) of cyclohexane and their half-widths are calculated in dependence of the temperature. The influence of the intrinsic line width turns out to be so small as to lie practically within the tolerance. The correlation functions of the true line profiles are found to be Lorentzian in good approximation. They are within the tolerance in conformity with the correlation functions of the orientational line shapes. Rotations of the C6H12-molecules around their C2-axes are supposed to be the cause for the occurring of a plastic phase.
The 9Be Photoneutron Cross Section from 17—25 MeV
Authors: Kneißl U. , Kuhl G. , Leister K. H. , Weller A.
Published: February 2015

We measured the 9Be photoneutron production cross section σ(γ, T, n) = σ(γ, n) + 2 σ(γ, 2n) + σ(γ, pn) in the energy range from 17 -25 MeV with quasimonoenergetic photons from positron annihilation in flight. In contrast to experiments of Thomas, Crawford and Thies (1972) and Hughes (1973), performed with bremsstrahlung photon sources we found no pronounced structure in this energy range.
High Magnetic Field Limit of the Kinetic Equation for a Lorentzian Gas of Particles with Spin
Authors: Waldmann L. , Köhler W. E.
Published: February 2015

The kinetic equation for a Lorentzian gas of particles with spin is investigated for a high external magnetic field. By time averaging over many precession periods the original kinetic equation decomposes into a set of separate equations. Each of them connects only elements of the distribution matrix with the same difference of magnetic quantum numbers. In particular, for the diagonal elements an equation of the Wang Chang-Uhlenbeck-de Boer type is obtained. The pertaining cross sections depend also on the field direction h . The eigenvalues of the dynamical operator are shown to have a positive real part. As an application, the h-dependent cross sections for spin-1/2-particles and the heat conduction in the high field limit are treated.
Waldmann-Snider Collision Integrals and Nonspherical Molecular Interaction. I. Collision Integrals for Pure Gases
Authors: Köhler W. E.
Published: February 2015

Collision integrals of the linearized Waldmann-Snider collision operator for pure gases are defined. General properties due to invariances of the molecular interaction are discussed. Effective cross sections are introduced and expressed in terms of convenient bracket symbols. The positive definiteness of the relaxation coefficients is proved. The approximation of small nonsphericity for the scattering amplitude is explained and consequences for the collision integrals are investigated. Molecular cross sections describing the orientation and reorientation of the molecular rotational angular momentum are defined. Expressions for effective cross sections relevant for the various nonequilibrium alignment phenomena are presented.
Scattering and Modulational Instabilities in Magnetized Plasmas
Authors: Yu M. Y. , Spatschek K. H. , Shukla P. K.
Published: February 2015

The decay of a high-frequency wave into a scattered and an electrostatic wave is investigated for a homogeneous magnetized plasma. For wave propagation in arbitrary directions, an equation for the scattered wave is obtained accounting for the effect of the non-linear current density produced by the three-wave interaction process. As an illustration, the propagation of electromagnetic waves perpendicular to the external magnetic field is considered. The growth rates and thresholds for the stimulated scattering and modulational instabilities are obtained. The influence of a weak inhomogeneity is also considered.
39K, 40K and 41K Nuclear Magnetic Resonance Studies
Authors: Sahm W. , Schwenk A.
Published: February 2015

The NMR lines of 39K and 41K have been investigated in solutions of many potassium salts in H2O, D2O, methanol and ethylenediamine and also in solid potassium halides. The NMR signal of the rare isotope 40K was detected for the first time. The ratio of the Larmor frequencies of 39K and 41K has been measured in various samples: υ(30K)/υ(41K) =1.821873 1 (9). No primary isotopic effect was to be detected within these limits of error (0.5 ppm). The concentration dependence of the chemical shift of the 39K resonance frequencies was determined. Using this dependence, the ratios of the Larmor frequencies of the nuclei 39K, 40K, and 41K for infinite dilution relative to the resonance frequency of 2H in D2O are given. The magnetic moments of the 39K+, 40K+, and 41K+ ions purely surrounded by water molecules are μ(39K+) =0.390 952 9 (24)μN, μ(40K+) = -1.296 262(9)μN , μ(41K+) =0.214 588 4 (13) μN without diamagnetic corrections. Comparison of these values with the results of atomic beam magnetic resonance experiments yields the hyperfine structure anomalies of all pairs of potassium isotopes and also the shielding of potassium nuclei by water molecules around the ions; the shielding constant is σ* (K+ in H2O vs. K atom) = - 0.000 105 2(8). For the liquid samples the relaxation times T2 and for the solid ones the relaxation times T2 and the line widths are given.
Dielectric Absorption and ESR Results on the Relaxation of some Manganese Complexes in Organic Solvents
Authors: Stockhausen M.
Published: February 2015

The limiting models - rotational or fluctuational process - for electron spin relaxation of Mn2+ in solution are discussed by comparison with dielectric correlation times. Free (solvated) ions presumably relax by the fluctuational, ionic complexes with static zfs by the rotational process. The latter conclusion requires the spectral density function to be more flat than the Debye function.
X-Ray Diffraction Study of Hep Metals. I. Line Broadening in Polycrystalline Cd Powder
Authors: Haider N. C. , Hunter S. H.
Published: February 2015

Powder Cd of 99.999% purity was prepared at room temperature (25 °C) and x-ray diffraction patterns were obtained using CuKaα radiation with Ni-filter. The line broadening was analyzed after incorporating the appropriate correction factors. At room temperature Cd was found to have large particle size (653 A), small root mean square strain (.001), small deformation fault probability a (.003). and negligible growth fault probability β(0). Compared to other hep metals which have been studied earlier and which have higher melting temperatures, metal Cd is much less affected by mechanical deformation at room temperature.
On Some Theoretical Aspects of the 1-Type Doubling Constant qe: Application to XYZ (C∞V) Type Molecules
Authors: Mohan N. , Müller A.
Published: February 2015

The relationship between the 1-type doubling constant qe and the centrifugal distortion constant De and the range of real values of qe for XYZ (C∞v) type molecules, is derived in detail. The experimental value of qe for many molecules is found to be in the neighbourhood of its minimum. The usefulness of qe in fixing a unique and accurate force field for XYZ (C∞v)type molecules is also discussed. A brief discussion of the nature of the errors arising due to the use of Dv , BV and υi in the calculation (for qe) is presented. The study of the mass effect on qe is also reported.
C ≡ N Frequency Shifts in Dinitrilo Complexes of Cd2+
Authors: Ali N. J. , Al-Janabi M. Y. , Shanshal M.
Published: February 2015

Reaction of CdCl2 with NC (CH2)n CN, n -1, 3, 4 and 5 produced new complexes. The C ≡ N frequency red and blue shifts were noticed in them. These are explained in terms of interaction between the 5pAO of Cd2+ and the MOs of the C≡N group.
Photodissoziation bei zweiatomigen negativen Halogenmolekülionen / Photodissociation of the Diatomic Molecular Negative Ions of Halogens
Authors: Rackwitz R. , Feldmann D. , Heinidee E. , Kaiser H. J.
Published: February 2015

Photodissociation measurements of F2
- , Cl2
-, Br2
- and I2
- in the photon energy range from 0.5 eV to 3 eV have been performed. Crossed beam technique has been applied. Absolute values from 10-18 cm2 to 10-17 cm2 are found.
Collisionless Plasma Oscillations, Their Residual Presentation and the Mechanism of Landau Damping
Authors: Ecker G. , Frömling G.
Published: February 2015

The description of the electron oscillations of a collisionless plasma by the usual residual presentation is insufficient in the initial phase of time development and for perturbations of small velocity spread. We derived criteria for the number of residual terms which have to be taken into account and obtain analytic expressions for the remaining integral. Decomposing the initial perturbation into velocity beams we show that Landau damping is due to phase mixing caused by free streaming of particle beams modified through the response of the main plasma body.