bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Dilution Diffusion of Tl+ in Molten NaNO3, KNO3 and RbNO3 Studied by Wave-Front-Shearing Interferometry
Authors: Okada Isao , Gustafsson Silas E.
Published: February 2015

The high-dilution diffusion of Tl+ in molten NaNO3 , KNO3 and RbNO3 has been measured with wave-front-shearing interferometry. For very low concentrations of TlNO3 the results are

D = 6.21×10-8 exp [-(18400± 800)/RT] in NaNO3 (316-387 °C),

D = 5.39×10-8 exp [-(18800±1400)/RT] in KNO3 (341-408 °C),

D = 1.87×10-7 exp [-(25800±2200)JRT] in RbNO3 (327-419°C),

where D is the diffusion coefficient in m2 s-1, R the gas constant in J K-1 mol-1 and T the temperature in K.

Comparisons are made with high-dilution diffusion of Na+, K+, Rb+, Cs+ and Ag+ ions in alkali nitrates, and it is found that both Ag+ and Tl+ diffuse faster than expected if the mass and the ionic radius were the sole parameters of importance, i. e. other parameters such as the polarizability also have an influence on the diffusion rate of an ion. For the system NaNO3 - TlNO3 , the interdiffusion coefficient has also been measured at 88.8, 73.8, 51.5 and 31.6 mol % NaNO3 .
Arachidate Layers on Ag and Au Substrates Detected by the A T R Method
Authors: Wähling G.
Published: February 2015

Monolayers of cadmium arachidate (thickness 26.8 A) are deposited on Ag and Au substrates. They can be detected by the resonance excitation of surface plasmons (ATR method). The number of monolayers is correlated with the displacement of the reflection minimum. The observed values of the position of the minima as well as the shape of the reflection curve are in agreement with the calculated ones, using a refractive index of cadmium arachidate of 1.52 in agreement with other measurements
Collisional Activation Spectra of Quaternary Phosphonium and Tertiary Sulfonium Cations Produced by Field Desorption
Authors: Weber R. , Borchers F. , Levsen K. , Röllgen F. W.
Published: February 2015

The collisional activation spectra of a variety of tetraalkyl phosphonium and trialkyl sulfonium ions generated by field desorption are reported. The fragmentation behaviour of the onium ions is compared with that of ammonium ions, reported earlier [4] and the corresponding open shell amine, phosphine and sulfide molecular ions. Cleavage of the heteroatom -carbon bond, with or without hydrogen rearrangement (i.e. alkyl and alkane loss) leads to prominent fragment ions in all onium ions. Pronounced heterolytic cleavage of this bond was only observed in sulfonium ions. No direct ɑ-cleavage of the cation is observed, however, ɑ-cleavage can occur in a second step after elimination of a substituent. This process leads to the base peak with ammonium ions, occurs less frequently in sulfonium ions and cannot be observed unequivocally in phosphonium ions. In addition, the collisional activatiou spectra of phenylalkyl phosphonium ions and chlorine containing quaternary phosphonium ions are discussed. It is demonstrated that collisional activation in conjunction with field desorption is a useful technique for the structure elucidation of onium cations
The Microwave Spectrum of Oxazole
Authors: Kumar Anil , Sheridan John , Stiefvater Otto L.
Published: February 2015

The dipole moments and the quadrupole coupling constants of the normal and the three mono-deuterated species of oxazole have been measured. The dipole moment of 1.50 ± 0.03 D is found to deviate by 10.8° from the external bisector of the CNC angle towards the C(2) carbon atom. The principal values of the quadrupole coupling tensor are determined as Xzz = -4.04 ± 0.02 MHz and Xxx - 1-66 ± 0.02 MHz along the axes in the molecular plane, so that the gradient perpendicular to this plane is Xyy = 2.38 MHz. The direction of the largest gradient deviates by 5.7° from the external bisector of the CNC angle towards the carbon atom C(4).

An attempt is made to correlate these results and the geometry of oxazole with the electron distribution in this molecule
Microwave Spectrum of Cyclopentene-3,5-dione
Authors: Mjöberg P. J. , Ljunggren S. O. , Bäckvall J. E.
Published: February 2015

The microwave spectra of cyclopentene-3,5-dione in the ground state and the first four excited states of the ring bending vibration have been studied in the frequency region 26.5 to 40.0 GHz and the corresponding rotational constants have been determined. The ground state spectrum of one isotopically substituted species, 4-deuteriocyclopentene-3,5-dione, has also been assigned. The following values of the ground state rotational constants (MHz) were obtained from the spectra:

From intensity and inertial-defect considerations the ring configuration was shown to be planar in the ground state. In addition, the nearly straight-line behaviour of the rotational constants as functions of the ring-puckering vibrational quantum number indicates that the ring-puckering vibration is nearly harmonic with a fundamental frequency of approximately 90 cm-1 . The electric dipole moment for the unsubstituted species in the vibrational ground state was found to be 1.680 ± 0.009 Debye units
Ionization of Unpolar Molecules by Alkali Ion Attachment on the Surface of Electrolytic Solutions Exposed to High Electric Fields
Authors: Röllgen F. W. , Ott K. H.
Published: February 2015

It is shown that mixtures of salts with low vapor pressure organic compounds deposited on field anodes can be used for surface ionization of paraffins by Li+ and Na+ ion attachment. The highest ionization efficiencies were obtained with emulsifying agents such as Tweens® mixed with Lil.
Phonon-Assisted Indirect Transitions in Cadmium Sulfate Crystals
Authors: Sunandana C. S. , Ramasastry C.
Published: February 2015

The fundamental absorption edge of “suprapur” cadmium sulphate (3CdSO4 · 8H2O) crystal occurs in the region below 200 nm. The power-law dependence of the optical density on photon energy suggests indirect electronic transitions made possible by the emission or absorption of 0.067 eV phonons. The indirect band gap (Eg′) at 300 K is 6.09 eV. The phonon energy of 0.067 eV is found to arise from one of the Raman-active modes (E ) of the sulphate ion. The band edge is found to shift monotonically towards higher energies at a rate of - 2.3 meV per K between 300 and 77 K. The laser Raman spectrum of the 3CdSO4 · 8H2O is also reported.
Temperature Dependence of Sensitized Photocurrents between 200 and 293 K
Authors: Killesreiter H.
Published: February 2015

With an oxacarbocyanine dye monolayer on the surface of a p-chloranil single crystal and sandwiched between metal electrodes the temperature dependence of sensitized photocurrents has been measured with this “dry” electrochemical cell in the temperature range from 200-293 K. The activation energy of 0.26 ± 0.02 eV is discussed in terms of a reaction scheme that involves a thermalization distance within the coulomb well of an intermediate state.
Temperature and Solvent Dependence of Vanadium-51 Chemical Shifts and Line Widths of Vanadyl-triisopropylate
Authors: Paulsen Kurt , Rehder Dieter , Thoennes Detlef
Published: February 2015

Line widths ⊿ν1/2 of 51V n.m.r. signals of vanadyl-triisopropylate VO(OPri)3 dissolved in tetrahydrofurane range from 10 to 610 Hz, increasing with decreasing temperature according to a theoretically proposed T-1/2 exp (E/RT) law, indicating that the molecular correlation time τc is the main factor influencing line widths in this system. With lowering of temperature, 51V-shielding decreases (the temperature gradient of the chemical shift δV is about - 0.5 ppm/K over a temperature range of 300-180 K), suggesting a loss of molecular symmetry due to solvation and association processes. In pentane, methylcyclohexane and diethylether, the δV/T and ⊿ν1/2/T correlations exhibit two inconsistencies at approximately 190 and 240 K which are attributed to the formation of clusters, and of oligomers {VO(OPri)3}n, respectively. The latter gives rise to a satellite line with an upfield shift relative to the monomeric species. Exchange interactions are discussed as a second factor affecting line widths.
Increased Nuclear Fusion Yields of Inertially Confined DT Plasma due to Reheat
Authors: Hora H. , Ray P. S.
Published: February 2015

The efficiency of energy release has been calculated here for fusion reactions in inertially confined plasmas of high density. It is found that inclusion of reheat due to absorption of the energetic alphas released by the reactions in the plasma itself predicts higher gains G due to ignition. Including losses by bremsstrahlung and fuel depletion we find G = 71 for 1 k J laser energy input with a compression of only 1000 times solid state density.
Resonant Interaction of Surface Plasmons with a Dye Monolayer
Authors: Wähling G. , Möbius D. , Raether H.
Published: February 2015

The interaction of surface plasmons with a dye monolayer having a rather small absorption band is discussed in this paper. Applying the ATR method surface plasmons were excited on a silver surface covered with a monolayer of arachidate (26.8 Å) and a monolayer of the dye.

The position, half-width and the depth of the reflection minimum are strongly dependent on the applied wavelength in the region of the absorption line. The essential features of the measured dependencies can be explained by a simple oscillator model.
Shock Wave Compression of NaCl Single Crystals observed by Flash-X-Ray Diffraction
Authors: Müller F. , Schulte E.
Published: February 2015

Flash-x-ray-diffraction patterns (FXD) with an exposure time of 4 ns of NaCl single crystals compressed by plane shock waves are obtained at pressures of about 30 kbar. From the diffraction patterns the compression is determined and compared with Hugoniot data. During shock load the lattice shows an uniaxial compression. While in case of measurements at the free surface an observation time of only a few nanoseconds is available, this experimental set-up allows an observation time of two microseconds.
The Influence of Photorefractive Index Change on Raman Scattering Intensities in LiNbO3
Authors: Nippus M. , Claus R.
Published: February 2015

The time dependent varying shape of the laser beam within the scattering volume in Raman scattering experiments on LiNbO3 influences the recorded spectra and can be studied spectroscopically by forward-, right angle-, and backward-scattering geometries. The recorded spectra allow a time resolved insight into the microscopic local changes of the refractive index. The decay constant of the scattered phonon intensity is a well defined function of the laser power. It furthermore showed to be characteristic for the individual sample. Raman spectroscopy thus seems to provide a method to determine the concentration of Fe-impurities. We have observed that ordinary photons influence the optically damaged regions of the sample whereas undamaged regions are left almost unchanged. Damped cut-in oscillations recorded when illuminating the sample alternatingly with ordinary and extraordinary laser light seem to originate from local fluctuations of an excited cloud of impurity electrons. The observation of undamped periodic break downs of the scattering intensity from polaritons and back scattered phonons is reported.
NMR Spectra of Alkali and Halogen Nuclei in Alkali and Halogen Salts
Authors: Gauß W. , Günther S. , Haase A. R. , Kerber M. , Kessler D. , Kronenbitter J. , Krüger H. , Lutz O. , Nolle A. , Schrade P. , Schüle M. , Siegloch G. E.
Published: February 2015

NMR signals of 7Li, 23Na, 35Cl, 39K, 79Br, 87Rb and 127I have been measured in various alkali and halogen salt powders relative to well defined aqueous solutions. With the known shielding constants of some of these solutions the nuclear magnetic shielding constants of the alkali and chlorine nuclei in crystalline powders were evaluated in the atomic reference scale. The theoretical values of the shielding constants in alkali halides do not agree even in the order of magnitude with the experimental ones in some cases.

For 23Na first-order and second-order quadrupole patterns have been observed and the quadrupole coupling constants are given.
Die Zeitabhängigkeit der Emissionsanisotropie und die Resonanzübertragung / The Time Dependent Emission Anisotropy and the Resonance Transmission
Authors: Kamiński J. , Schmillen A. , Kawski A.
Published: February 2015

Fluorescing solutions excited by linearly polarised light have a time dependent emission anisotropy of the fluorescence due to exchange of excitation energy. By an approximation method we calculate numericaly the decay of this anisotropy for a mean concentration of one molecule in a sphere with the critical transfer radius Ro and for times t ≦ τ . The result differs from the decay of the anisotropy with exp (- a√t/τ), given by the Förster Theory, by a factor 0.61 in the exponent only. A comparison with own measurements gives for anthracene in acethylcellulose a critical transfer radius of 28.5 Å.
Photoelectron Spectroscopy of Heterocycles. Fluorene Analogues
Authors: Ruščić B. , Kovač B. , Klasinc L. , Güsten H.
Published: February 2015

The He(I) photoelectron spectra of fluorene and its analogues, biphenyl, dibenzofuran, carbazole, dibenzothiophene, and phenanthrene were measured and analyzed. The assignment of the π-electron ionizations using orbital interaction and symmetry arguments for the constituent parts of the molecules indicates that the energy levels of the fluorene analogues can be reproduced within a few percent of error. A close linear correlation between the π-ionization energies and the eigenvalues of the corresponding HMO-orbitals is obtained as well.
Stoßwellen-Druckmessungen an Aluminium, Polymethylmethacrylaten und Polyvinylchloriden mit Hilfe von Röntgen-Absorption / Shock-Wave Compression Measurements of Aluminium, Polymethylmethacrylate and Polyvinylchloride by X-ray-Absorption
Authors: Hollenberg K. , Müller F.
Published: February 2015

Pressure-compression curves for Aluminium, Polymethylmethacrylate and Polyvinylchloride are determined in the pressure range from 100 kbar to 300 kbar by flash x-ray absorption measurements. Results are in good accordance with free-surface data. Certain systematic deviations of shock adiabates obtained by x-ray absorption from the results obtained by other authors using the free-surface method, are discussed.
Die Kinetik des thermischen Zerfalls von ClNO2 / Thermal Decomposition of ClNO2
Authors: Knauth H.-D. , Martin H.
Published: February 2015

ClNO2 decomposes incompletely at temperatures between 353 K and 373 K in the nonpolar inert solvent C7F15Cl according to

2 ClNO2=2 NO2+Cl2. (a)

Some ClNO is formed as by-product according to

2 ClNO2 = 2 ClNO+O2 . (b)

The reactions were followed photometrically by the arising NO2 . The time dependence of the brutto-reaction is described on the basis of the reaction scheme

ClNO2⇄NO2+Cl (1, - 1); NO3+NO2⇄NO+O2+NO2 (5, - 5);

ClNO2+ClNO2⇄Cl2+2NO2 (2, - 2); NO+ClNO2⇄ClNO+NO2 (6, - 6);

Cl+ClNO2⇄Cl2+NO2 (3, - 3); ClNO+ClNO2⇄NO±Cl2+NO2 (7, - 7);

NO2+ClNO2⇄NO3±ClNO (4, - 4); Cl+ClNO⇄Cl2+NO (8, - 8).

Arrhenius parameters for the steps (1) and (2) were obtained:

A1/s-1 = 1016.47±0.78, E1/kJ mol-1 = 152.3 ± 5.4;

A2/cm3 mol-1 s-1 = 1012.99±0.02 E2/kJ mol-1 = 88.7 ± 0.8.

The other parameters entering the rate equations were determined at 373 K as k-1/k3 = 1.5 ± 0.3; k4/cm3 mol-1 s-1 = 0.17; k7/cm3 mol-1 s-1 = 11.2. The enthalpies and entropies of the overall reactions (a), (b) and N2O4 = 2 NO2 (c) were measured directly (c) or indirectly:

(a) (b) (c)

⊿RH/kJ mol-1 46.4 83.7 65.3

⊿RS/J K -1 mol-1 61.8 85.7 97.8

(standard state 1 mol cm-3, T = 363 K).

Former investigations of the reaction in the gas phase and in solution which were interpreted exceptionally by step (1) followed by the fast step (3) are now interpreted on the basis of the new reaction scheme discussed here and are found to be consistent with it.
Chemilumineszente Anregung von Li-Atomen bei Reaktionen von Li mit Cl2 , SF6 und CF2Cl2 / Excitation of Li-atoms by Chemiluminescence Reactions of L i with Cl2, SF6, and CF2Cl2
Authors: Roeder M. , Fricke U. , Neuert H.
Published: February 2015

The chemiluminescence radiation resulting from reac­tions of Li atoms with Cl2, SF6, and CF2Cl2 has been studied using an atomic Li beam entering the reaction chamber at gas pressures of 10-5 to 10_3mbar. The spectra were re­gistered with aim scanning grid spectrometer (McPherson) using a 9558 QB multiplier. The spectral lines from excited Li atoms are prominent in all the cases. The dominant reactions seem to be of the same type as they have been found in the earlier studies on alkali metal and halogen gas chemiluminescence reactions. In order to explain the for­mation of the higher excited atomic levels, however, a re­action M2 + X2 → MX† + MX must be considered.
Structure of Molten Sn-Zn-Alloys by Means of Neutron Diffraction
Authors: Knoll Walter , Steeb Siegfried
Published: February 2015

Neutron diffraction experiments were performed with four molten Sn-Zn-alloys and the two molten elements Sn and Zn. The total structure factors and the pair correlation functions are given. The observed small angle scattering leads to the result that pairs of equal atoms predominate within the range of medium concentrations.
Formation of Cyanopolyynes in Gas Discharges
Authors: Winnewisser G. , Creswell R. A. , Winnewisser M. , Winnewisser M.
Published: February 2015

Cyanodiacetylene, H(C ≡ C)2 CN has been produced by a radiofrequency discharge in a mixture of acetylene, HCCH, and hydrogen cyanide, HCN. This reaction is of astrophysical importance, since it lends support to the possibility of the ion-molecule formation scheme of producing long carbon chain molecules in interstellar sources. From a measurement of the J = 4←3 transition of HC5N the nuclear quadrupole coupling constant eqQ = - 4.242 (30) MHz was determined.
Microwave Spectrum of (SiH3)2X, X = O,S, r0-Structure, Molecular Electric Dipolemoment and Barrier to Internal Rotation of Disilylsulfide
Authors: Dössel K. F. , Sutter D. H.
Published: February 2015

The rotational spectrum of SiH3-S-SiH3 in its vib-torsional ground state has been investigated in the frequency range between 8 and 40 GHz. From the absolute frequencies and torsional splittings a rigid-top-rigid-frame r0-structure could be derived. The molecular electric dipole moment was determined from the second order Stark effect of some AA-species rotational transitions. The analysis of the microwave spectrum of the related molecule SiH3-O-SiH3 was yet unsuccessful. However several features of the observed spectrum rend support to the idea of a “quasi-linear” double rotor molecule with a relatively low energy hump for the linear configuration of the Si-O-Si-chain.
Heuristic Considerations Suggesting a Role for Electron Pairing in Thermodynamically Consistent Pathways of Enzyme Catalysis
Authors: Conrad Michael
Published: February 2015

Nuclear motions accompanying enzyme catalysis are described in terms of a hypothetical reaction mechanism in which instabilities of electronic structure arise from short-lived pairing resonances of parallel spin electrons. A pairing interaction is proposed which has its basis in confinement constraints imposed by complex formation.
Electronic Theory for Cleaved Alloys: Effects of Off-Diagonal Disorder
Authors: Masuda Kin-ichi
Published: February 2015

The tight-binding type theory for cleaved alloys by Bennemann et al. has been extended to include the effects of the random transfer integrals (off-diagonal disorder). The chemisorption and segregation behavior of cleaved alloys is investigated in detail including both the diagonal and off-diagonal disorder. It is demonstrated that the effects of the off-diagonal disorder are very important for the electronic properties of cleaved alloys. The theory has further been used to study the electronic structure of metal surfaces with substitutional disorder as well as to investigate the changes in the density of states due to the order-disorder phase transition in chemisorbed layers.
Notizen:On the Translational Part of the Lagrangian in the Poincaré Gauge Theory of Gravitation
Authors: Rumpf Helmut
Published: February 2015

Using differential forms we postulate a guiding principle yielding the quadratic Lagrangian of von der Heyde.
Notizen:Solvent Effect on Emission Anisotropy of Fluorescencé of Polar Molecules
Authors: Kawski A. , Kukielski J. , Kamiński J.
Published: February 2015

The emission anisotropy (EA) of 4-Dimethyl-amino-4′- nitrostilbene (DNS), 4-Amino-4′-nitrostilbene (ANS) and 2,5-Di(4-biphenylyl)oxazole (BBO) was observed to be decreasing with increasing dielectric constant ε of the solvent. The effect is interpreted as an influence of the Onsager reaction field on the volume of the solvent shell, which in the excited state is smaller in solvents with larger ε. This favors the depolarisation by the irrregular Brownian rotation.
Notizen:Phosphorescence Decay in Thallium-Doped Ammonium Chloride
Authors: Chaudhari S. , Joshi T. R. , Joshi R. V.
Published: February 2015

The phosphorescence decay rates of thallium-doped ammonium chloride (NH4Cl:Tl) phosphors, prepared by crystallization from aqueous solution, have been studied at room temperature for near-ultraviolet emission. The effects of impurity concentration as well as thermal and/or mechanical treatment on the decay rates have been examined. Phosphorescence centres consisting of a Tl+ion and a nearby negative ion vacancy are suggested to be responsible for the observed luminescence decay. The changes in the decay characteristics after pretreatments are explained on the basis of the location of the centres in normal and distorted regions of the host lattice.
A Remark on Joint Probability Distributions for Quantum Observables
Authors: Bugajski Sławomir
Published: February 2015

A simple formal result concerning joint probability distributions in quantum mechanics is obtained. It is shown that some relatively weak properties of the joint distributions cannot be satisfied in the scope of standard quantum mechanics.
Electronic Structure and Transport Properties of Polypeptide: Polyglycine Chain with Hydrated Side Group
Authors: Kertesz M. , Koller J . , Ažman A.
Published: February 2015

A calculation on a model compound is performed to test the Brillouin mechanism for the transport properties of proteins.
Eine PMO-theoretische Untersuchung der benzogenen Diels-Alder-Reaktion polycyclischer aromatischer Kohlenwasserstoffe / APMO-theoretical Treatment of the Benzogenic Diels-Alder Reaction of Polycyclic Arom atic Hydrocarbons
Authors: Zander M.
Published: February 2015

Experimental reaction rates of the benzogenic Diels- Alder reaction of polycyclic aromatic hydrocarbons with maleic anhydride are correlated with the corresponding bislocalization energies calculated by the PMO method. The observed relations between the localization energies of the reacting centres and the topology of the hydrocarbons can be qualitatively understood on the basis of Clar’s π-sextet model of polycyclic systems and Polansky’s pars orbital method.
Interaction Potentials of Hg-Ar from Temperature Dependent Absorption Spectra
Authors: Petzold H. C. , Behmenburg W.
Published: February 2015

The temperature dependence of the absorption spectrum k(v̄) of Hg-Ar-mixtures in the range 30-1000 cm-1 about the center of the Hg-line at v̄0 = 39425 cm-1 (λ0 = 2536.5 Å) has been investigated in the temperature interval 473 -1273 K. The measurements were carried out at number densities 1.0 x 1017-9.1 X 1018 cm-3 for Hg and 9.4 x 1018-9.7 x 1018 cm-3 for Ar. Potentials for the Hg-Ar-system in the thermal energy range originating from the Hg-states 61S0 and 63P1 have been deduced from the data. It turned out that they differ considerably from Lennard-Jones-functions. By comparison of the observed spectra with calculations on the basis of quantummechanical theory of collisional line broadening it is concluded that transitions from free translational states of Hg-Ar-pairs as well as bound and quasi-bound vibrational states of the Hg-Ar-molecule contribute to the formation of the satellite structure on the short wavelength side of the Hg-line.
The Quadrupole Coupling Constants of 1,2,5-Thiadiazole
Authors: Stiefvater Otto L.
Published: February 2015

The nitrogen quadrupole coupling constants along the inertial axes o f 1,2,5-thiadiazole are determined as Xaa = 0.90 ± 0.01 MHz, Xbb = - 3.13 ± 0.06 MHz, Xcc = X (⟂) = 2.22 ± 0.06 MHz, and Dobyns and Pierce’s value for the dipole m om ent is confirmed as μ = μa = 1-58 ± 0.02D. (The uncertainties are three standard deviations.) Comparison o f these data with their counterparts in related compounds leads to speculation that the direction of the main field gradient in the molecular plane deviates from the SNC bisector towards the sulphur atom by Ɵ ~ 5° - 10°. From this assum ption the principal in-plane coupling constants are Xradial = Xzz ~ - 3.82 MHz and Xtangential = Xxx ~ 1.60 MHz, with uncertainties of ± 0.20 MHz due to a probable error of ± 2° in the assumed direction (Ɵ = 8°) of the z-axis o f the field gradient tensor.
The Rotational Zeeman Effect of Molecules with Low Barrier Internal Rotation. II. Derivation of the Effective Rotorsional Hamiltonian
Authors: Engelbrecht L. , Sutter D .H .
Published: February 2015

Theoretical expressions for the molecular parameters in the effective rotorsional Hamiltonian in a strong magnetic field are derived from a second order perturbation treatment within the electronic states which was adapted to the presence of a large am plitude internal motion. The technique developed m ay be o f use also in other applications where it should be necessary to go beyond the Born-Oppenheimer approximation. By use o f the theoretical expressions it is now possible to use experimentally determined Zeeman data to derive “experimental values” for the molecular electric quadrupole moments, the paramagnetic susceptibilities, the second m om ents o f the electron charge distribution, and the sign of the molecular electric dipole moment also for low barrier molecules.
Nachweis von BrO2 im Belousov-Zhabotinskii-System
Authors: Försterling H. D. , Schreiber H. , Zittlau W.
Published: February 2015

From the analysis of the absorbance of an oscillating Belousov-Zhabotinskii-system (initial concentrations 0.1 m malonic acid, 0.1 m bromate and 10-4 m Ce4+ in 2n sulfuric acid) it is concluded that the absorbance in the spectral region from 400 to 600 nm is mainly due to the oscillations of Ce4+ and BrO2, and that no Br2 is to be detected. The maximum concentrations of Ce4+ and BrO2 during the oscillations are in the order of 10-5 m and 10-7 m respectively. The results are in accordance with theoretical considerations basing on the mechanism of Field, Körös and Noyes.
Uranisotopentreiinung mit einem Gegenstromwirbelrohr
Authors: Becker E. W. , Bley P. , Ehrfeld W. , Lenné H.
Published: February 2015

Uranium isotope separation in countercurrent vortex tubes has been investigated experimentally using a mixture of uranium hexafluoride and a light auxiliary gas as the feed gas. A minimum value of 7000 kW h/SW U was obtained for the ideal specific energy consumption which is higher by a factor of 2.7 than the corresponding value of the separation nozzle. Further specific expenditures for this type of vortex tube, e.g. the suction volume and the length of separator required per unit separative work have been found to be also unfavorably high in view of a commercial application.
Quadrupole Splitting of Vanadium-51 N.M.R. Signals in Nematic Phases
Authors: Rehder Dieter , Paulsen Kurt , Lechert Hans
Published: February 2015

The 51V n.m .r. spectra of vanadyl esters dissolved in nematic liquids show a seven line system which is due to a first order quadrupole interaction. Quadrupole splittings vary from 3.6 to 19.3 kHz.
Detection of a-Phase Precipitates in Decomposing NiH6 by Bitter Powder Pattern
Authors: Jonitz D. , Bauer H. J.
Published: February 2015

The application of a decoration technique basing on the settlement of iron single domain particles made it possible to identify directly small ferromagnetic a-phase particles in early states of decay of nickel hydride. In crystals of different orientation of the surface the shape and orientation of particles could be defined.
Formation and Decomposition of Nitrides on Iron Surfaces
Authors: Ertl G. , Huber M. , Thiele N.
Published: February 2015

The formation (by interaction with ammonia) and decomposition of nitrides on clean Fe surfaces was studied by means of Auger electron spectroscopy, x-ray photoelectron spectroscopy, thermal desorption spectroscopy, and scanning electron microscopy. The N atoms may exist in various forms with quite similar electronic properties, viz. as chemisorbed layer (= "surface nitride"), dissolved in α-Fe or γ-Fe, as γ′-nitride (= Fe4N) or as e-nitride, depending on temperature as well as pressure and duration of interaction with NH3. There is no noticeable chemical shift of the ionization energies of the Fe core levels, indicating that the bond is essentially covalent. The activation energy for the decomposition of e-nitride into Fe4N + N2 is about 27 kcal/mole, that for the decomposition of Fe4N into Fe+N2 ranges between 51 and 57 kcal/mole, depending on the mode of preparation. The latter values are identical to those found previously for the desorption of N2 from various Fe single crystal planes and indicate that the decomposition of the chemisorbed "surface nitrides" is the rate-limiting step which prevents the spontaneous decom-position of the metastable bulk iron nitrides.
Mechanism of Ammonia Decomposition on Tungsten; NH3 and ND3 Isotope Effect
Authors: Shindo H. , Egawa C. , Onishi T. , Tamara K.
Published: February 2015

Light and heavy ammonia were decomposed on a clean tungsten foil at 973-1123 K and at pNH₃, ND₃ ≈ 0.2 Torr. The nitrogen uptake and the kinetics of the formation of nitride layers were examined during the course of the reaction. The amount of nitrogen chemisorbed (or the thickness of the nitride layers formed) at higher pressures was found to be appreciably larger from NH3 than from ND3. Addition of hydrogen had no effect on the thickness of the nitride layer nor on the rate of ammonia decomposition. These facts support the concept of a dynamic balance between two consecutive rate determining steps: supply of chemisorbed nitrogen from ammonia into the surface and consumption of the chemisorbed nitrogen through its desorption from the surface to form nitrogen molecules.
Oblique Illumination Stereoscopy in the Shadow Electron Microscope
Authors: Dowell W. C. T.
Published: February 2015

Oblique illumination, although accompanied by distortion, provides a simple method of obtaining stereoscopic images in a shadow electron microscope. It is not necessary to tilt the specimen.
Constitutive Relations for Moving Plasmas
Authors: Hebenstreit Helmut
Published: February 2015

A covariant form of Ohm’s Law for bianisotropic plasmas is set up connecting the four-dimensional current density with the field tensor through a material tensor of order three. This tensor is represented by two four-dimensional material tensors of order two, which are closely related to the usual threedimensional conductivity tensors; its symmetry properties are investigated and relations between its components and those of the three-dimensional material tensors are established. In addition a covariant constitutive equation for a plasma is formulated using the polarization model, where the four-dimensional current density is substituted by a polarization tensor. Thereby the plasma properties - like the dielectric and magnetic properties of a medium - are expressed by a material tensor of order four, whose representation is generalized for bianisotropic media
Calculation of Covariant Dispersion Equations for Moving Plasmas
Authors: Hebenstreit Helmut
Published: February 2015

The four-dimensional treatment of wave propagation in an homogeneous anisotropic plasma leads to a four-dimensional algebraic wave equation, where the solubility condition (dispersion equation) is given by the vanishing of a 3 × 3 subdeterminant. The covariant representation of such a defect algebraic system of equations is treated generally for N dimensions and its solubility condition is given by the vanishing of a determinant (having the same rank as the tensor operator of the system), whose elements are covariant themselves. The dispersion equation is explicitely given for a gyrotropic plasma, where the four-dimensional conductivity tensor can be represented by four-dimensional projectors
Three-Dimensional Elliptical Centered MHD Equilibria
Authors: Lortz D. , Nührenberg J.
Published: February 2015

MHD equilibria are considered which are purely elliptical and centered with respect to the magnetic axis up to third order in the distance from the magnetic axis. Their β-value is not governed by conventional estimates. In particular, three-dimensional, toroidal, medium aspect ratio (A ~ 20), medium β (~ 20%) equilibria without longitudinal current of this type are constructed
Theoretical and Experimental Investigation on Dipole Moment of Synthetized yt-Base in the Ground and Excited States
Authors: Gryczyński I. , Jung Ch. , Kawski A. , Paszyc S. , Skalski B.
Published: February 2015

The electric dipole moment of yt-Base calculated by the CNDO/S and JNDO/S method is μg = 3.42 D and μg = 3.74 D in the ground state and μe = 4.41 D and μe = 5.67 D in the first excited ππ*-state, respectively, μg and μe being nearly antiparallel. Measurements of absorption and fluorescence spectra of yt-Base in aprotic solvents of different polarity yielded μg = 3.8 D and μe = 4.3 D and the directions of dipole moments were found to be nearly antiparallel.

This comparison may be considered as an indication for the ππ* character of the observable first excited state, although the CNDO/S-and JNDO/S-calculations predict a nπ*-state as the lowest lying excited state
Experimental Study of Balmer-α Stark Broadening
Authors: Ehrich Horst
Published: February 2015

The Stark-broadened line profiles of Hα and Dα have been measured in a wall stabilized argon arc at an electron density of ne = 1.4 × 1016 cm-3. Consistent with earlier experiments the obtained line profiles exhibit severe discrepancies to theoretical profiles based on the approximation of static ions and the line profiles were found to depend on the mass of the radiating atom. The measured half width of Dα is about 15% smaller than the Hα-value. Recent calculations based on the “Model Microfield Method” greatly improve agreement with experiment
Nuclear Quadrupole Coupling in 5-Membered Ring Oxygen and Sulphur Heterocyclic Compounds; Studies by Nuclear Quadrupole Resonance and Ab Initio Molecular Orbital Calculations
Authors: Redshaw Mavis , Palmer Michael H. , Findlay Robert H.
Published: February 2015

The 14N nuclear quadrupole resonance spectra for the compounds 2a, b, 3b, 4b, 5a, b, 6b have been obtained at 77 K and the asymmetry parameter and coupling constants extracted. A comparison of these with microwave spectral results, shows that small but systematic differences occur between the solid and gaseous states. There is a high level of agreement for the observed coupling constants from NQR or MW spectra and the ab initio calculations in both magnitude and direction. This enables us to extract further principal axis data from the observed microwave spectra, and to predict with some confidence the axes and coupling magnitudes for other members of the series where incomplete determinations are available. Variations in coupling constants with structure are discussed
Relationship Between New Structural Data on Clinoptilolite and Its Behaviour in Ion-Exchange and Heating
Authors: Galabova Iliana M.
Published: February 2015

Low degrees of removal of K in ion-exchange as well as alterations of relative intensities of (0k0) X-ray reflections under heating have been found for clinoptilolite. These observations are in good accord with the newly provided structural data of clinoptilolite
A Concept to Relate the ZFS Parameter D of Aromatic Hydrocarbons to Molecular and Electronic Structure
Authors: Bräuchle Chr. , Kabza H. , Voitländer J.
Published: February 2015

New aspects for the interpretation of the zero field splitting parameter D of the lowest excitet triplet state of polycyclic hydrocarbons are presented. A model connecting the dipole-dipole interaction between the two triplet electrons with Clar’s concept of electronic sextets is employed. It follows that even in highly condensed aromatic molecules the probability for the two triplet electrons to be localized on one C6-ring unit can be relative high.

This concept is outlined taking the experimental D-values of a series of pyrene derivatives as an example
Heat of Mixing and Activities in Liquid Al-Sn Alloys
Authors: Waseda Y. , Jacob K. T. , Tamaki S.
Published: February 2015

The microscopic electron theory based on the pseudopotential formalism has been applied to the calculation of the heats of mixing and of activities in liquid Al-Sn alloys. The calculated values for both quantities were found to be in reasonable agreement with the experimental data.
The Microwave Spectrum of Fluoroacetylene in Ground and Vibrationally Excited States and Some Laser Enhancement Effects
Authors: Jones Harold , Rudolph H. D.
Published: February 2015

The microwave spectrum of HCCF and DCCF has been investigated in all vibrational states with energy up to 1500 cm -1 . In the ground state and low-lying vibrational states mm-wave measurements up to 210 GHz were made. In some cases a detailed analysis of the vibrational state rotation spectrum including the effects of l-type resonance, and the determination of the anharmonicity constant gtt was possible. The rotational spectra of combination states of the type (vt = 2, vt′ = 1) were observed and partially analyzed, which is, to our knowledge, the first time this has been accomplished. The low-lying vibrational states of 13 C species of HCCF and DCCF were also observed.

The 9.4 μm P(14) CO2-laser line was observed to produce a reduction in intensity in the ground state and an increase in intensity in the v3 = 1 excited state J = 0 → 1, 1 → 2, 2 3 transitions of DCCF.
Notizen: A New Determination of the Half-Life of 194Hg
Authors: Probst H.-J. , Alderliesten C. , Jahn P.
Published: February 2015

Using experimental data on excitation functions of 197 Au(p, x n) 198 -x Hg reactions the half-life of 194 Hg has been determined to be 367 ± 55 y.
Notizen: Positron Annihilation in Noble Gas Mixtures
Authors: Grover P. S.
Published: February 2015

The annihilation decay constant of positrons in (He + Ne + Ar) mixtures has been computed and its dependence on concentration and electric field investigated. This constant is found to depend quite sensitively on the nature of the gas mixture and the applied electric field.
Channelling Effects in Electron Induced X-Ray Emission from Diatomic Crystals
Authors: Taftø J.
Published: February 2015

The variation of x-ray emission with direction of the incident beam has been studied in diatomic crystals of ZnS, ZnSe and FeS2 using an electron microscope at 80 keV attached with a Si(Li) x-ray detector. The interpretation is based on the Bloch wave picture taking into account absorption and diffuse scattering of the electrons
Über die extrem hohe thermodynamische Stabilität von Pd-Th-Legierungen / On the Extremely High Thermodynamic Stability of Pd-Th Alloys
Authors: Schaller H.-J.
Published: February 2015

The thermodynamic properties of Pd-Th solid solutions containing up to 16 at.% Th have been determined by the e.m.f. method between 700 and 800 °C with CaF2 solid electrolyte cells. The mixing behaviour of the alloys is characterized by extreme negative deviations from ideality, up to -410 kJ/mol for the partial molar excess free energy of Thorium. The extraordinary stability is attributed to electronic interactions brought about by the transfer of the Thorium valence electrons to the electron gas of the alloy. At vanishing Thorium concentration the resulting bonding contribution to the thermodynamic excess quantities is determined by the difference of the Fermi energies of the pure components, approximately equal to the difference of the work functions. Including the lattice distortion as a small additional effect, the mixing behaviour of these and other palladium alloys can be well described
High-Dilution Diffusion of K + , Rb + , Cs + , and Tl + in the Molten System (Li-K)NOs Studied by Wave-Front-Shearing Interferometry
Authors: Odawara Osamu , Okada Isao , Kawamura Kazutaka
Published: February 2015

The high-dilution diffusion coefficients of K+, Rb+, Cs+, and Tl+ in molten LiNO3-KNO3 mixtures are measured over a wide range of temperatures and concentrations by means of wavefront- shearing interferometry. A slightly positive deviation from linearity is found for the concentration dependence of the diffusion coefficient of K+ , Rb+, and Tl+, while no deviation is found for Cs+ within the experimental error. This is qualitatively discussed from the viewpoint of the ionic radii, the free space in the solvent, and the interaction between the diffusing and the surrounding ions
Calculation of the Knight Shift in Palladium
Authors: Krieger R. , Voitländer J.
Published: February 2015

The direct and core-polarization contributions to the Knight shift in palladium metal have been calculated taking an enhancement factor of 10 for d- and 1.28 for s-electrons. We found a large negative contribution of - 3.88% for the core electrons and a comparatively small direct contribution of 0.18% for s-electrons on the Fermi surface. Together with an estimated contribution of 0.36% for conduction electrons in s-orbitals, but not on the Fermi surface, the calculated total amount of - 3.34% is in good agreement with the experimental value of - 4% obtained by the Jaccarino plot for palladium at 0 K
On the Radioactivity of Fly Ashes from Coal Power Plants
Authors: Papastefanou C. , Charalambous St.
Published: February 2015

The radioactivity of Greek lignites and their ashes was studied. It was found that the radionuclides in them belong to the uranium series. Fly ashes are relatively rich in radioactivity. Concentrations up to 7 · 10-5 g/g and 12 pCi/g were measured for 238U and 226Ra, respectively. The associated hazards from radioactivity escaping from stacks of thermopower plants or when fly ashes are used as subtitutes of cement in concrete are evaluated.
A Contribution to the Microwave Double Resonance Technique and Measurements of Collision Induced Transitions
Authors: Dreizier H. , Schrepp W. , Schwarz R.
Published: February 2015

A construction for a versatile absorption cell is presented, which may be used for a large variety of double resonance experiments in the radiofrequency, microwave and millimeter wave region. Some measurements of collision induced transitions are reported.
Condensed Aromatics. Part II The Five-Parameter Approximation of the In-Plane Force Field of Molecular Vibrations
Authors: Bakke Arvid , Cyvin B. N. , Whitmer J. C. , Cyvin S. J. , Gustavsen J. E. , Klaeboe P.
Published: February 2015

An approximate force field for the in-plane vibrations of condensed aromatics with only five parameters is investigated. Calculated frequencies are given for naphthalene, anthracene and coronene. The results are compared with values from other, more elaborate methods, mainly the Califano-Neto force field. The five-parameter approximation is found to be useful as an aid in assignments of experimental frequencies. It appears to give amazingly good results considering its great simplicity and small number of parameters. New experimental infrared and Raman data for anthracene and coronene are given. Especially some new features in the Raman spectrum of anthracene are reported in some details.
Temperaturfunktionen der durch Mehrfachdotierung mit chiralen Verbindungen in einer nematischen Phase induzierten Helixganghöhe / Temperature Dependence of the Induced Helical Pitch of a Nematic Phase Using Several Chiral Additives
Authors: Göbl-Wunsch A. , Heppke G.
Published: February 2015

A helix structure can be induced in nematic phases by adding chiral compounds. In general the helix pitch increases with temperature. It is shown that by using two suitable doping agents, each of which would give different senses of helix rotation when used individually, a particular temperature behaviour can be obtained. Depending on the concentrations, a temperature independent pitch, for example, or a helix inversion can be achieved. The results of experiments using the nematic phase N 4 (Merck) show good agreement with the theoretically predicted temperature dependence of the pitch.
Jahn-Teller E-e Problem: Diagonalization by Means of a Transformed Basis
Authors: Birkhold M. , Wagner M.
Published: February 2015

A unitary transformation is applied to the E-e Jahn-Teller problem. The eigenfunctions of the diagonal part of the transformed Hamiltonian are utilized for a Ritz diagonalization procedure. Results are given for basic sets of 12, 20 and 42 functions and compared with the respective conventional calculations. In the transformed picture the exact results are approached in a different manner than in the original one and thus the reliability of the numerical work is improved.
Analytische Näherungslösungen für Ladungsdichten bei Elektronenstoßionisation Analytical Approximate Calculation for Electron Impact Ionization Generated Ion Charge State Densities
Authors: Hertenberger G. , Zeidl H.
Published: February 2015

The time-dependent development of ion charge state densities resulting from ionization of a gas by an electron beam has been calculated with a nonlinear system of coupled differential equations. In the approximation within the presented treatment the nonlinearity is caused by small contributions due to recombination processes.
Energieübertragung zwischen gleich- und ungleichartigen Molekülen in Lösung.
Authors: Kawski A. , Stoń M.
Published: February 2015

The p-Terphenyl (donor) and 4-aminobenzophenon (acceptor) system in solvents of different static dielectric constants was studied by the fluorescence quenching due to nonradiative energy transfer. The dependence of I ṽ/n4 (I ṽ is the overlap integral of the fluorescence spectrum of donor and the absorption spectrum of acceptor, n the refractive index of the solvent) on the polarity of the solvents was investigated. From the linear relation between (ηD
0/ηD - 1) (ηD
0/ηD is the relative quantum yield of the donor fluorescence) and I ṽ/n4 the intermoleculare distance R for a given acceptor concentration in different and also mixed solvents were determined.
Notizen:MMM Profiles of HeI Lines: Ion Dynamics Effect
Authors: Mazure A. , Goldbach C. , Nollez G.
Published: February 2015

Stark profiles of the HeI 4471 and 4922 Å overlapping lines are calculated by the Model Microfield Method. Even at high densities (3·1016 cm-3) an ion dynamics effect is exhibited by varying the reduced mass of the radiator -perturber system or the ionic temperature.
Topological Resonance Energy is Real
Authors: Godsil C. D. , Gutman I.
Published: February 2015

It is proved that the zeros of the matching polynomial of a graph are real. Hence, topological resonance energy is also a real quantity.
“Molecular Properties” in Intense Magnetic Field
Authors: Singh U. Chandra , Kelkar V. K.
Published: February 2015

The simple LCAO method has been used to find the effect of intense magnetic fields on the internuclear distance and the binding energy of the H2
+ ion. The Spruch functions of the Hydrogen atom have been chosen as the basis. The results show that the magnetic pressure greatly affects the internuclear distance and the bonding energy. Req and Ebind as a function of α, the classical cyclotron radius of the electron, are given.
Miscibility Gaps in Fused Salts. Note X. The Reciprocal Ternary System K, Li/Br, F
Authors: Margheritis Chiara , Flor Giorgio , Sinistri Cesare
Published: February 2015

Solid-liquid and liquid-liquid equilibria in the reciprocal ternary system K, Li/Br, F were fully measured.

The projection of the miscibility gap occupies 20.8% of the composition square; the upper critical point of the gap is along the stable diagonal at 953°C and xLIF = 0.70.

Attempts to predict the liquid-liquid equilibria by means of the conformal ionic solution theory using temperature independent interaction parameters lead to an incorrect symmetry of the gap. The symmetry can be improved if the temperature dependence of the interaction parameters of the binary mixtures is taken into account.