bluuebunny/crossref_metadata_2025_split huggingface dataset:
Notizen:Solvent Effect on Emission Anisotropy of Fluorescencé of Polar Molecules
Authors: Kawski A. , Kukielski J. , Kamiński J. 
Published: February 2015

Abstract
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

Abstract
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.
Interaction Potentials of Hg-Ar from Temperature Dependent Absorption Spectra
Authors: Petzold H. C. , Behmenburg W. 
Published: February 2015

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Constitutive Relations for Moving Plasmas
Authors: Hebenstreit Helmut 
Published: February 2015

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
On the Radioactivity of Fly Ashes from Coal Power Plants
Authors: Papastefanou C. , Charalambous St. 
Published: February 2015

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
“Molecular Properties” in Intense Magnetic Field
Authors: Singh U. Chandra , Kelkar V. K. 
Published: February 2015

Abstract
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.