bluuebunny/crossref_metadata_2025 huggingface dataset:
Vibrational Energy Transfer in CHF3 -Mixtures
Authors: Frank K. , Hess P.
Published: February 2015

The vibrational relaxation times for pure CHF, and CHF3 diluted in H2, D2, Ar, Kr and Xe are 0.55; 0.01, 0.025, 2.6, 4.8, and 5.6 /μsec atm at 298 K. These measurements complete previous results obtained for the systems CHF3-He, Ne, Ar. Correlation of the rare-gas results according to SSH-theory shows that relatively small rotational contributions may be expected for the heavy collision partners Kr and Xe.
Electric Quadrupole Interaction of 20F in a KZnF3 Single Crystal
Authors: Ackermann H. , Dubbers D. , Grupp M. , Heitjans P. , Stöckmann H.-J. , Wanczek K. P. , Recker K. , Leckebusch R.
Published: February 2015

Nuclear magnetic resonance measurements were carried out on neutron activated 20F(T1/2=11s) nuclei in a single crystal of KZnF3. The quadrupolar splitted NMR spectrum, detected via the 20F β-radiation asymmetry, could be observed using a radio frequency modulation technique. The quadrupole coupling constant was determined to e2 q Q/h= + (12.0 ± 1.5) MHz at room temperature. The sign of e2 q Q was obtained from a simultaneous γ-ray anisotropy measurement on the succeeding 20Ne transition. Utilising a calculated field gradient of the fluorine atom, an fQ = 4.6% is determined. This value is compared with literature data of similar compounds.
Wirkungsquerschnitte für Umladung bei Stößen einfach-positiver Atomionen mit keV-Energien / Cross Sections for Charge Changing of Single-positive Atomic Ions with keV Energy
Authors: Lehmann B.
Published: February 2015

Cross sections have been measured for some charge changing processes occuring when single-positive atomic ions, with 12 - 60 keV, collide with Kr atoms. The ions are H+, C+, N+, O+ and S+. The apparatus only permitting registration of charged collision products, the observed processes are electron loss and double electron capture by the primary ions.
Structure and Compressibility of Au-Co Melts
Authors: Steeb Siegfried , Bek Richard
Published: February 2015

Alloys of the Au-Co system containing 0, and 100 at.% Co were investigated at temperatures between 10 and 20 °C above the liquidus by means of thermal neutron (wavelength 1.20 Å) and X-ray (Mo-Kα) diffraction. The interference functions show no additional maxima or deformations. Radial distribution functions were obtained and from these the coordination numbers NI and nearest neighbour distances rI were obtained and plotted versus the concentration together with the curves to be obtained for the ideal case and the case of total segregation. With both plots the experimental values lie between these curves thus indicating a tendency to segregation within these melts.

The velocity of ultrasound was measured in molten Au-Co alloys containing 0, 10, and 100 at.% Co within the temperature range from 995 °C to 1700 °C. The adiabatic compressibility was calculated from the velocity. From it the partial structure factors aij(0) and Skl(0) for zero momentum transfer were obtained. According to the results, the melts of the Au-Co system show a weak tendency to segregation.

Thus it could be proved by two independent methods, that Au-Co melts show a tendency to segregation.
X-Ray, NMR, and NQR Investigations of the Crystal Structure and Charge Distribution of Sodium Tetrachloroaluminate, NaAlCl4
Authors: Scheinert W. , Weiss Alarich
Published: February 2015

On single crystals of NaAlCl4 the NMR- and NQR-spectra of 23Na, 27Al, and 35Cl were studied at room temperature. The crystal structure of NaAlCl4 has been refined. A comparison of the NMR (NQR) data with the crystal structure data shows that the electric field gradients (EFG) at the chlorine sites are mainly determined by the partial covalency of the Al-Cl bond, whereas the EFG at the aluminum sites is determined by the small deviations of the AlCl4 ion from tetrahedral symmetry and by the influence of the lattice. ∣ e2 q Q/h ∣ (23Na) proves the dominant ionic character of sodium in the lattice. The experimental results for the crystal structure show minor deviations from Baenziger's data.

The NMR (NQR) data at T=22 °C are [atom (∣e2 q Q/h ∣ / MHz; η)]: 23Na (1.1117±0.0012; 0.2153 + 0.0005); 27Al (1.4895±0.0012; 0.3375±0.0011) ; 35ClI (23.033±0.030; 0.182 ±0.025); 35ClII (22.520 ±0.010; 0.270 ± 0.005) ; 35ClIII (21.646 ±0.003; 0.315±0.007); 35ClIV (22.410±0.016; 0.197±0.010).
Acetyl Cyanide III. Vibrational Spectrum and Vibrational Analysis
Authors: Heise H. M. , Scappini F. , Dreizler H.
Published: February 2015

The infrared spectrum of gaseous acetyl cyanide, CH3COCN, has been recorded from 90 - 3200 cm-1. The Raman spectrum of the liquid phase has been measured between 100 and 500 cm-1. The eighteen fundamental vibrations have been assigned, mainly on the basis of the infrared band contours, and a normal coordinate analysis has been made.
A Microwave Study of Collision-Induced Transitions between M-Resolved-Rotational levels of OCS
Authors: Mäder H. , Schrepp W. , Dreizler H.
Published: February 2015

Four-level MW-MW-double resonance experiments on the rotational Stark-levels J=0, 1, 2 and 3 of OCS have been performed employing both frequency and time domain techniques. The results indicate significant deviations from first order dipole collisional interaction.
On a Two-sphere Problem and the Radius of the Muon
Authors: Mitra A. K.
Published: February 2015

The 2p-1s transition energies for a model of two bound spheres have been calculated. A hint towards the estimation of the muon radius has thus been given.
Messungen an einem N2-Laser mit Dämpfungskondensatoren / Measurements on an N2-Laser with Damping Capacitors
Authors: Miyashiro S. , Gronig H.
Published: February 2015

A low cost pulsed molecular nitrogen laser with damping capacitors has been constructed and tested. The design in-corporates a bandsaw blade as a multiple negative electrode structure and twenty small damping capacitors along the laser channel for discharge. This design is very advantageous not only for practical use but also for the study of the dynamics of a nitrogen laser.
A Metric Theory of Gravitation without Minimal Coupling of Matter and Gravitational Field
Authors: Goenner H.
Published: February 2015

A metric theory of gravitation is suggested which reduces to Einstein's theory in the case of vanishing matter. If matter is present, in the Lagrangian formulation of the theory the principle of minimal coupling is given up by directly linking the matter variables to the curvature tensor. The theory contains a free parameter of dimension length. It is considered not to be a universal constant but a length characteristic for the mass of the material system described.

Results diverging from those of General Relativity are to be expected for regions with high curvature i. e. especially for gravitational collapse and dense phases of the cosmos. An exact, static and spherically symmetric solution with constant matter density is discussed; it indicates that, possibly, gravitational collapse is avoided.
Spatial Variations of Spontaneous Magnetization in a Layered Ising Model
Authors: Ränder K.
Published: February 2015

The extrema of the position-dependent spontaneous magnetization in a periodically layered two-dimensional Ising model are calculated exactly. Their asymptotic behaviour for infinite width of the surrounding homogeneous sublayer is given. The perturbations caused by the neighbouring sublayers on this extremum in a very thick sublayer are shown to be decoupled. Thus the asymptotic decay of the magnetization far from a single layer-shaped inhomogeneity can be inferred from the quoted asymptotics of an extremum, and it is found to be d-3/2exp (-d/ξ₁˂ where d is the distance to the inhomogeneity and ξ₁˂ the correlation length in the underlying homogeneous lattice. The connection of this decay law to the asymptotic decay of correlations is dicussed.
A Problem Connected with the Schott Term in Classical Electrodynamics
Authors: Sorg M.
Published: February 2015

It is shown that the well-known "4/3-problem" of the old Abraham-Lorentz model for the extended electron is still present in Rohrlich's redefinition of the electromagnetic four-momentum, if the latter is applied to an accelerated electron. The notorious factor 4/3 emerges now in connection with the Schott term. Since this term is an indispensable constituent of the Lorentz-Dirac equation of motion for the radiating electron, this equation appears to be not completely reliable.
Zusätzliche dielektrische Verluste starrer, polarer Moleküle in verdünnter Lösung bei Frequenzen oberhalb des Maximums der Debye-Absorption / Additional Dielectric Loss of Rigid Polar Molecules in Dilute Solutions at Frequencies in the Far Infrared [FIR]
Authors: Noerpel W.
Published: February 2015

The dielectric loss of ten polar molecules in dilute solutions has been measured in the 0.3 GHz to 300 GHz range. Besides the Debye-absorption of the polar molecules, in all solvents, i.e. heptane, cyclohexane, mesitylene and decalin there could be separated an additional part of dielectric loss in the range of mm-waves. This absorption has been approximated by a Debye-curve to gain the step of dispersion and the time-constant.

The dielectric loss of the unpolar solvents themselves, which is due to collision induced dipole moments, has also been investigated. The results are discussed and compared with the FIR-absorption of the polar molecules.
Analyse dünner Schichten binärer Verbindungen mit der Elektronenstrahlmikrosonde / Analysis of Binary Compound Thin Films with the Electron Microprobe
Authors: Haeussler E. , Saur E.
Published: February 2015

Analysis of Binary Compound Thin Films with the Electron Microprobe Two methods for the quantitative analysis of binary compound thin films by electron micro-probe have been developed and applied on some compounds with A 15-structure. Appropriate calibration curves for these compounds are given and compared with results of three theoretical or semiempirical methods showing fairly good agreement.
Microwave Spectrum, Nuclear Quadrupole Coupling Constants, Dipole Moment, and Structure of Chlorine Pentafluoride, ClF5
Authors: Bodenseh H. K. , Hüttner W. , Nowicki P.
Published: February 2015

Several rotational transitions in the ground vibrational state of 35ClF5 and 37ClF5 have been measured. From the frequency data the following constants have been derived: B0(35ClF5) = 3550.272(4) MHz; B0(37ClF5) = 3545.885 (4) MHz; DJ = 0.76(9) kHz; DJK = -0.67 (15) kHz; e Q q(35ClF5) = 43.93(8) MHz; e Q q(37ClF5) = 34.63(6) MHz; μ = 0.536(10) D.

The bond angle Fax-Cl-Feq is estimated at 86.5(1.0)°.
Thermodynamic Excess Functions of Binary Liquid Mixtures with Chain Association of One Component*. Part I: The Excess Gibbs Free Energy GE/RT
Authors: Becker F. , Kiefer M. , Rhensius P. , Schäfer H. D.
Published: February 2015

In this paper equilibrium models for the calculation of the excess Gibbs free energy of binary liquid mixtures are developed, the component A of which undergoes chain-forming self-association whilst the component B acts as an 'inert' solvent. It is shown that the extension of the well-known chain-association model of Mecke and Kempter, in which the probability of chain prolongation is assumed to be independent of chain length, is unable to establish satisfactory results because it does not exhibit sufficient unsymmetry. Reduction of the probability of chain growth with in-creasing chain length leads to an improved model with the geometric series replaced by the exponential series. This model, in which only two parameters are used, i. e. the equilibrium constants K for mutual solvation of A and B, and ρ for self-association of A, allows fitting of isothermal experimental GE /R T literature data on cycloalkanol-cycloalkane, alkanol-alkane, and NMF -CCl4 systems within the limits of experimental error. Compared with the two-parameter Wilson equation which gives equally small standard deviations, our equilibrium model has the advantage of allowing passage from GE to HE data and of being applicable to liquid-liquid equilibria.
SEM Studies of Cholesteric Liquid Crystals
Authors: Voss J. , Voss B.
Published: February 2015

A special method of preparation of cholesteric liquid crystals is reported, which is useful for the investigation of cholesteric structures with very small pitches. This freeze-etching method makes it possible to observe pitches with scanning electron microscopy without influencing the structure by solvent molecules.
Different Types of Chaos in Two Simple Differential Equations
Authors: Rössler Otto E.
Published: February 2015

Different types of chaotic flow are possible in the 3-dimensional state spaces of two simple non-linear differential equations. The first equation consists of a 2-variable, double-focus subsystem complemented by a linearly coupled third variable. It produces at least three types of chaos: Lorenzian chaos, "sandwich" chaos, and "horseshoe" chaos. Two figure 8-shaped chaotic regimes of the latter type are possible simultaneously, running through each other like 2 links of a chain. In the second equation, a transition between two different types of horseshoe chaos (spiral chaos and screw chaos) is possible. While sandwich chaos allows for a genuine strange attractor, the same has not yet been demonstrated for horseshoe chaos. Unlike the situation in the analogous 1-dimensional case, an emergent period-3 solution is not necessarily stable in the horseshoe. Since chaos is a "super-oscillation" (emergent with the third dimension), the existence of "super-chaos" is postulated for the nect level.

A six-minute, super-8 sound film, demonstrating the different behavioral modes and their bifurcations in the 2 equations, has been prepared. Chaos sounds as musical as a snore.
Molecular Orbital Theory of the Electronic Structure of Organic Compounds I. Dioxodiazacycloalkanes
Authors: Marañon Julio , Sorarrain Oscar M. , Grinberg Horacio , Lamdan Samuel , Gaozza Carlos H.
Published: February 2015

The stability of some heterocyclic compounds derived from the condensation of succinic and glutaric anhydrides with aliphatic diamines is compared using calculated values for the total energies. Further, some results derived from the electronic population analysis and the available experimental data are used to give information about the corresponding electronic structure. The CNDO/2 and INDO methods have been used for the calculations.
The Structure of 1,2,4-Thiadiazole by DRM Microwave Spectroscopy
Authors: Stiefvater Otto L.
Published: February 2015

Rotation spectra of 1.2,4-thiadiazole have been studied for naturally occurring 34S-, 13C-and 15N-species of the normal and the 5-d1 form, and the 12 sets of moments of inertia have been used to determine the substitution structure in the two principal axes systems. Agreement within less than 0.0005 Å and 0.02° for distances and angles, respectively, between the two independent sets of structure parameters was obtained through the use of the rotation of axes under substitution in combination with the first and second moment conditions.

The averaged bond lengths (in Å) and angles (in degrees) are:

S(1) - N(2) : 1.6490 C(5)S(1)N(2) : 92.75

N(2) - C(3) : 1.3166 S(1)N(2)C(3) : 107.09

C(3) - N(4) : 1.3663 N(2)C(3)N(4) : 120.12

N(4) - C(5) : 1.3133 C(3)N(4)C(5) : 107.74

C(5) - S(1) : 1.7071 N(4)C(5)S(1) : 112.30

C(5) - H(5) : 1.0785 S(1)C(5)H(5) : 123.90

C(3) - H(3) : 1.078 N(2)C(3)H(3) : 119.94

The H(3) atom was assumed on the external bisector of N(2)C(3)N(4) at a distance of 1.078 Å from C(3).

Geometric features of the four thiadiazoles are compared, and the method used in the structure calculation is discussed.
Near Infrared Absorption of Ethylene between 8200 cm-1 and 9500 cm-1 to High Pressures and Temperatures
Authors: Nees F. W. , Buback M.
Published: February 2015

The near infrared absorption of pure ethylene in the region of the second overtone of the C-H stretching fundamentals (8200 cm-1 to 9500 cm-1) was measured at supercritical temperatures (Tc = 9.5 °C) between 22 °C and 200 °C from 0.7 bar to 3000 bar.

The density and temperature dependence of bandshape, maximum frequency and absorption intensity are reported and discussed. The bands observed within a wide range of experimental conditions are assigned to combination and overtone modes.

The molar integrated intensity B̅λ determined between the wavelength of maximum absorption and the high frequency absorption boundary was observed to be independent of pressure and temperature. This enables spectroscopic concentration determinations on ethylene in high pressure - high temperature phase equilibria and reactions.
Second Virial Coefficients of Ground State Nitrogen Atoms
Authors: Guidotti C. , Arrighini G. P. , Capitelli M. , Lamanna U. T.
Published: February 2015

Second virial coefficients of ground state nitrogen atoms have been calculated in the temperature range 6000 - 20000 K. The results have been obtained using experimental potentials for the states 1∑g
+, 3∑u
+
5∑g
+ and of the nitrogen molecule and an ab initio Heitler-London potential for the 2∑u
+ repulsive potential.

Differences up to a factor of 5 are found between the present second virial coefficients and the corresponding values of Kessel'man et al.
Kinetics of Fast Brominations by the Use of Rotating Platinum Electrode
Authors: Rao T. S. , Mali S. I.
Published: February 2015

The utility of the rotating platinum electrode for the study of fast reactions has been shown by evaluating the specific reaction rates of brominations of m-acetotoluidide, acetanilide and o-acetotoluidide in aqueous solution.
Bestimmung der Elektronenanzahldichte in einem Helium-Plasma / Determination of the Electron Density in a Helium Plasma
Authors: Einfeld D. , Sauerbrey G.
Published: February 2015

A comparison was made between electron densities determined from the emission coefficient of the continuum radiation and from Stark broadening of line profiles using a wall stabilized pulsed arc plasma with electron temperature T = 38 000 K and electron density from 2 × 1022 m−3 to 3.5 × 1022 m−3. The measured peak separation in the profiles of the He I lines 447.1 nm and 492.2 nm was consistent with that predicted by G.B.K.O.- and B.C.S.-theory and agrees with the experimental results from Bötticher, Roder, and Wobig. The measured halfwidth of the He I 501.6 nm line agrees with the results from Kusch and shows a discrepancy to the G.B.K.O.-theory by a factor about 1.7. The results for the Stark broadening halfwidth of the He II lines 468.6 nm and 320.3 nm lie between the values from G.K.S.-and K.G.-theory.
Computersimulation der Rückstreuung schneller schwerer Ionen an einkristallinen (001)-und (111̅)-Goldoberflächen / Computer Simulation of the Backscattering of High Energy Ions from (001)- and (111̅)-surfaces of Au-Single Crystals
Authors: Schmidt H. , Güttner K.
Published: February 2015

A computer program for following the trajectories of high energy ions in an fcc-lattice has been written to evaluate the reflection rate of high energy ions with grazing incidence to (001)- and (111̅)-Au-surfaces. The calculation yields a rapid decrease of the reflection rate for penetration directions close to low-index atomic planes. It can be shown that this result is caused by channeling of the ions between the atomic planes.
Microwave Spectrum of hexa-Deutero Dimethyl Selenide in the Ground and Excited Torsional States
Authors: Pandey G. K. , Dreizler H.
Published: February 2015

The ground state rotational spectra of 80Se and 78Se species of the hexadeutero dimethyl selenide have been measured in the region from 5 to 40 GHz. In both the cases, rotational and centrifugal distortion constants have been determined by a least square fit to about thirty transition frequencies. For the (CD3)2
80Se molecule, fourteen rotational transitions in the excited torsional states ṽ = l1, and ṽ = l2 were also recorded, out of which nine appeared as well resolved triplets. The potential barrier parameter V3 and the angle a between one of the ‘top axes’ and the ‘b axis’ have been determined by a least square fit of the mean value of the observed splittings in the ṽ = l1 and l2 states. The methyl top moment of inertia Iα was kept fixed at 6.35 amu Å2 , which is half of the observed inertia defect in the molecule.
The Zeeman Effect in the Rotational Spectrum of Carbonyl Chloro Fluoride
Authors: Scappini F. , Guarnieri A.
Published: February 2015

The rotational Zeeman effect of FClCO is reported. The Chlorine nuclear gI-factor, the molecular g-factors, gaa , gbb , and gcc , and the magnetic susceptibility anisotropics, (2 χaa- χbb - χcc) mole and (2 χbb - χcc - χaa) mole, are obtained from the spectrum.

Some derivative molecular quantities are calculated.
A Model of the Structure of Liquid Antimony
Authors: Orton B. R.
Published: February 2015

The interference function from liquid antimony at 600 °C, obtained by Waseda and Suzuki, has been reproduced using a model based on two hard sphere interference functions (packing density, 0.41 diameters 3.11 Å and 2.33 Å). Agreement obtained using the model is better than that existing between various independent diffraction measurements.
Magnetisches Dipolmoment der zweiatomigen (IVa/VIa)-Molekeln 1Σ-Grundzustand / Magnetic Dipole Moments of Diatomic (IVa/VIa)-Molecules in their 1Σ Ground State
Authors: Honerjäger R. , Tischer R.
Published: February 2015

Rotational gJ-factors of the following (IVa/VIa)-molecules have been measured:

72Ge32S: -0.06828(11), 120Sn80Se: 0.03007(10),

74Ge80Se: -0.03765(6), 120Sn130Te: -0.02212(13),

74Ge130Te: -0.03193 (10), 208Pb32S: -0.06440 (4),

120Sn32S: -0.06120(7), 208Pb80Se: -0.02764(7).

The systematics of the rotational magnetic moments of class (IVa/VIa) -molecules are discussed.
Effect of a Ring on the Stability of Polycyclic Conjugated Molecules
Authors: Bosanac Slobodan , Gutman Ivan
Published: February 2015

A graph theoretical method is developed which enables to calculate the contribution of a partic­ular ring to the total π-electron energy of a conjugated molecule.
Ion-Molekül-Reaktionen und Ladungsaustausch bei Stößen von O– auf O2 / Ion-Molecule Reactions and Charge Transfer in Collisions of O– on O2
Authors: Vogt D. , Dreves W. , Mischke J.
Published: February 2015

Investigations of the cross section for the reaction O- + O2 → O2
- + O have been made for laboratory kinetic energies 0-100 eV. The reaction shows a sharp maximum in the cross section at low energies (5 eV lab.). By the use of the primary ion 18O- it can be shown that above 20 eV (lab.) there is only charge exchange whereas in the lower energy region ion-molecule-reactions as well as charge exchange occure. The reaction O- + O2 → O+ + … has also been observed above 27 eV (lab.).
The Double Diffraction Model for LEED-Intensity Spectra of the Clean Pt(100) Surface
Authors: Heinz K. , Heilmann P. , Müller K.
Published: February 2015

The intensity spectra of the superstructure diffraction spots of the clean platinum (100) surface are presented for normal or nearly normal incidence. Their gross features are interpreted in terms of multiple diffraction contributions. It is shown that most of the maxima in the spectra can be explained by double diffraction processes from an idealized pure hexagonal surface layer and quadratic bulk layers. Alternative models in which the surface layer exchanges already all occuring reciprocal lattice vectors would predict additional peaks which, however, do not arise. Therefore superstructure features of the surface layer are assumed to be of second order. Thus double dif­fraction involving only idealized hexagonal and quadratic structures seems to dominate the diffraction behaviour of clean Pt(100).
Comparative FTR- and Ramanspectroscopic Studies of Fundamental Mode Frequencies in LiNbO2 and the Present Limit of Oblique Phonon Dispersion Analysis
Authors: Schuller E. , Claus R. , Falge H. J. , Borstel G.
Published: February 2015

The assignments of fundamental mode frequencies in LiNbO3 determined by IR-and Raman scattering-experiments show some characteristic differences. Comparative frustrated total reflection (FTR) -and Raman scattering-studies were carried out in order to find the origin of these discrepancies. The most serious deviation was due to the fact that in one case the ordinary phonon is observed by Raman scattering whereas the extraordinary mode is recorded only by FTR. It has been shown, on the other hand, that the oblique phonon dispersion technique did not provide arguments for the correct assignments. The main limit of the method is due to the fact that the influence of exciton states on polaritons hitherto is taken into account only by a constant high frequency dielectric 'function' (ε∞). The uncertainty in the choice of a suitable ε∞-value allows fittings of quite diverging sets of experimentally determined fundamental frequencies.
NMR Investigation of Order Fluctuations, Self-Diffusion and Rotational Motions in the Nematic Liquid Crystal MBBA by T1-Relaxation Spectroscopy
Authors: Graf V. , Noack F. , Stohrer M.
Published: February 2015

We report on measurements of the proton spin T1 relaxation dispersion at various temperatures in the nematic phase of the liquid crystal MBBA in the Larmor frequency range from 2 kHz to 270 MHz, which exceeds previous studies by more than 3 orders of magnitude. The new results cannot be interpreted in terms of either order fluctuations or self-diffusion as recently proposed by Doane et al.1 and Blinc et al.2, respectively. Instead, the dispersion and its temperature dependence indicate the significance of at least three relaxation mechanisms, namely order fluctuations (OF), self-diffusion (SD) and rotation of the molecular ellipsoids about the short axis (R). The combined OF-SD-R model presented in this work allows a quantitative analysis of the experimental findings! The correlation times and activation energies of the three molecular reorientations evaluated from the T1 dispersion by means of a computer optimization procedure are in essential agreement with data provided by other spectroscopic methods [light scattering, tracer technique, dielectric relaxation], but differ from former NMR conclusions.
Systematic Patterns in the E1 Decays in 21Ne and 23Na: A Means of Identifying High Spin States?
Authors: Pilt A. A.
Published: February 2015

The El decays from members of the lowest Kπ= 1/2- bands in 21Ne and 23Na are shown to exhibit remarkable, but dissimilar, patterns, which can be reproduced with a simple two-parameter expression. This may have useful application in identifying high-spin members of the Kπ= 1/2- and 3/2+ bands in both nuclei.
Population Density Measurements in a Partially Ionized Freejet Expansion Flow
Authors: Kimura Akira , Nishida Michio
Published: February 2015

Population densities of the 4p and 5p levels of argon atoms were measured along a freejet centerline of partially ionized argon in a low density plasma wind tunnel. The measured axial distribution of the 4p[3/2] level population has been compared with a theoretical prediction using a modified Thomson's formula for the excitation cross sections.
17O Nuclear Magnetic Resonance Studies in Water of Different Isotopic Composition
Authors: Lutz O. , Oehler H.
Published: February 2015

17O and 2H Fourier transform NMR studies have been made in water with varying contents of hydrogen isotopes. Chemical shifts of 17O as a function of 2H contents and as a function of the hydrogen ion concentration are given. The ratios of the Larmor frequencies of 17O and 2H in water are used for evaluation of a magnetic moment of 17O in water. The deuterium isotope effect on the 17O NMR line in water is (3.08 ±0.20) ppm to lower frequency for deuterium oxide. No 17O shift was found in deuterium oxide with high 18O enrichment
Problems Occurring in Depth Concentration Profiling
Authors: Büger P. A. , Blum F. , Schilling J. H.
Published: February 2015

Results of the depth profiling of a laser mirror are reported and discussed. The sample was bombarded with 40Ar+, 32O2
+ and 16O- in order to establish optimum conditions. It was found that the bombardement by means of 16O- results in the best depth concentration profile
Non-LTE Line Transfer with Diffusion of Excited Atoms
Authors: Düchs D. F. , Oxenius J.
Published: February 2015

The classical problem of radiative transfer in a spectral line, due to two-level atoms, in a homogeneous medium is reconsidered. It is pointed out that the source function used up to now in the literature neglects the diffusion of the excited atoms. In many cases this assumption is not justified. In the low-temperature limit kT ≪ hv, the correct source function, allowing for diffusion of excited atoms, obeys an integro-differential equation
Die magnetische Nahordnung in Manganfluorid bei Temperaturen oberhalb des Neel-Punktes / The Magnetic Local Ordering in Manganese Fluoride at Temperatures above the Neel-Point
Authors: Dräger K.
Published: February 2015

For temperatures above the Neel-point the existence of antiferromagnetic clusters in MnF2 is established by magnetic resonance. In the temperature range between 80 K and 440 K the ESRintensity is quantitatively described by a cluster model. The excitation energy is computed to be about ΔE = \10 cm-1. It is shown that the bonding within this antiferromagnetic cluster originates in isotropic exchange interaction between next nearest neighbours, as the model gives a coupling constant of J = 1.21 ±0.07 cm-1. The connection with exchange effects of exciton states is established
Generalization of the Moment Method of Maxwell-Grad for Multi-Temperature Gas Mixtures and Plasmas
Authors: Weinert Ulrich , Suchy Kurt
Published: February 2015

A coupled system of balance equations is derived for the coefficients of orthogonal expansions of the velocity distribution functions. The orthogonal functions are not specified, but the initial func­ tions must be local Maxwellians with different temperatures for different species of particles. Closed expressions for the matrix elements of the non-linearized Boltzmann operator are given, whose dominant terms are determined and compared.
Die physikalischen Grundlagen der Uran235-Anreichcrung nach dem Trenndusenverfahren
Authors: Becker E. W. , Bier W. , Bley P. , Ehrfeld U. , Ehrfeld W. , Eisenbeiß G. , Rosenbaum F.-J. , Schmid E.
Published: February 2015

In the separation nozzle process for enrichment of U-235 the kinetic energy of the jet is con­ centrated in the heavy fraction of the H2/UF6 mixture. Flow measurements with free molecular probes and separation experiments have shown that this energy can be utilized in a so-called double deflection nozzle to increase significantly the overall isotope separation effect.
On the Absorption Spectrum of Isoquinoline and 3-Mcthylisoquinoline in Tetrahydrofuran and n-Paraffin
Authors: Kawski A. , Gryczyǹski I. , Kojro Z. , Janic̀ I.
Published: February 2015

The quasilinear absorption spectra of isoquinoline and 3-methylisoquinoline have been studied in tetrahydrofuran and n-paraffin solvents at 77 °K. An analysis of the vibrational structure in the first electronic excited singlet state (S1 is given. Different multiplicities of the absorption spectra have been studied and explained.
Spektren und Abklingprozessc der Mn(II)-Lumineszenz in Alkalichloriden; Untersuchung ihrer Konzentrationsabhangigkeit in MnCl2/LiCl / Spectra and Decay Processes of the Mn(II)-Luminescence in Alkali Chlorides; Investigation into their Dependence on Concentration in MnCl2LiCl
Authors: Oelkrug D. , Bina E.
Published: February 2015

Luminescence emission spectra, excitation spectra and decay curves of manganese (II) in alka­ line chloride host lattices were measured at room temperature and 77 K. In most samples the decay curves deviate strongly from an exponential function. Concentration and temperature dependence of the results and a comparison with the homogeneous phases of manganese (II) compounds leads to the following conclusion: In LiCl the statistical incorporation of Mn(II) predominates strongly; an interaction dependent on concentration between Mn (II) -ions and cationic lattice defects could be detected. In NaCl, isolated and linked MnCl6-octahedra have to be considered also at very low Mn (II) -concentrations. In KCl, pairs and bigger aggregates of linked octahedra occur much more frequently than the isolated MnCl6 units. In RbCl a uniform new phase of rubidiumchloro-manganate with linked MnCl6-octahedra is formed. The situation in CsCl is quite similar to that in RbCl, but there exists an additional metastable phase with MnCl4-tetrahedra.
A Simple Model for Liquid or Amorphous Metals
Authors: Blétry J.
Published: February 2015

The structure of liquid or amorphous metals is described by means of an harmonic approxima­ tion where atoms vibrate around the equilibrium positions of a random hard sphere network. This model depends on three parameters, of which the only adjustable one is the atomic vibration frequency, which is shown to be proportional to the Debye frequency of the corresponding crystalline phase. The atomic diameter is deduced from the position of the structure factor first peak and turns out to be equal to the Goldschmidt diameter. The packing fraction temperature variations are at­ tributed to presence of a variable number of randomly distributed atomic holes and deduced from density measurements. Good agreement with experimental structure factor determinations is found for a wide variety of liquid metals.
Phasentrennung als Folge der Konkurrenz zwischen „statistischcr“ und „chemischer“ Vermischung / Interpretation of Phase Separation as the Result of a Competition between "Statistical'' and "Chemical" Mixing
Authors: Becker Friedrich , Kiefer Michael , Rhensius Peter , Schäfer Hans-Dieter
Published: February 2015

The fact that common thermodynamic conditions are valid for all known types of critical phases (liquid-liquid, liquid-gas, and "gas-gas") suggests that a common principle for the interpretation of material phase instability from a molecular point of view must exist. In this paper we show that the principle of competition between "statistical mixing" (i. e. random mixing) and "chemical mixing" (i. e. mixing effected under the influence of chemical interactions) can give this common inter­ pretation. If the equilibrium states resulting from both types of mixing are sufficiently different, phase separation occurs. We refer to our earlier papers (since 1972) in which we have applied this principle to describe liquid-liquid phase equilibria by "chemical" models, using the equilibrium constants of exchange equilibria between nearest-neighbour complexes as a measure of "chemical" mixing. In this paper we show that the well-known reduced gas-liquid coexistence curve, T/Tc =f(q/qc), can accurately be fitted by a very simple "mixture" model of molecules A with "vacan­ cies", provided that the contributions of both statistical and chemical mixing are incorporated into the formula for GE. From a discussion of the application to "gas-gas" phase equilibria in the hyper­ critical region it results that the weight factor r, by which the contribution of statistical mixing enters into GE, must depend on the density of the gas mixture. Phase separation can only occur if, by increasing pressure, the contributions to GE of statistical and chemical mixing have reached the same order of magnitude. From an attempt to apply the same principle to solid-liquid equilibria it is shown under which external conditions a critical point for this type of phase transition can be expected.
The Microwave Spectrum of Silylisothiocyanate, SiH3NCS
Authors: Dössel K.-F. , Robiette A. G.
Published: February 2015

The J → J+1 transitions (J = 8, 9, 10 and 11) in the microwave spectrum of SiH3NCS have been assigned for the vibrational ground state and for the states ν10 = 1, 2 and 3. The results extend earlier work, giving more precise values for several of the molecular constants. Resonances in the excited vibrational states have been analysed: from these, values are deduced for the anharmonicity constant g10,10 and the vibrational interval ν10=1→2. The spectra of molecules isotopically substituted with 29Si, 30Si and 34S have been reassigned, and the resulting rs coordinates are in excellent agreement with bond lengths determined by electron diffraction.
Dipole Moments and Absorption Spectra of 2-Pyridyl-Phenyl Sulphide and 2-Pyridyl-Phenyl Sulphone
Authors: Galasso Vinicio , Pappalardo Giuseppe C. , Scarlata Giuseppe
Published: February 2015

The electric dipole moments in benzene solution have been measured for the title compounds and analysed in terms of the conformations of these molecules in solution. The origin of the electronic absorptions have been interpreted by means of a theoretical approach (CNDO/S-CI) and, to­ gether with the S02 stretching vibrations, have been com­ pared with the corresponding spectral features observed for the analogous related diphenyl and di-2-pyridyl compounds.
Nuclear Magnetic Relaxation in the Presence of Quadrupole Nuclei
Authors: Kimmich Rainer
Published: February 2015

Nuclear magnetic relaxation formulae are given for dipolar nuclei interacting with quadrupolar nuclei. The following cases are distinguished: High-and low-field case with respect to the quadrupole energy levels and, on the other hand, quasi rigid lattices and tumbling lattices with respect to molecular motions.

As examples of these cases, the proton T1-dispersion of Polyvinylchloride (quasi rigid lattice) and of protein solutions (tumbling lattice) are discussed and compared with theory. It is shown that the influence of the interaction with quadrupole nuclei is normally not negligible.

PVC shows a quadrupolar dip below room temperature as an especially remarkable consequence of the interaction with chlorine. An oscillator model is discussed in order to explain the molecular motion at low temperatures.

Proteins contain imino-groups acting as relaxation centers and mediating the contact to the aqueous solvent via hydrogen bonds. These relaxation centers can explain the low absolute values of the longitudinal relaxation times in protein solutions. Furthermore, several effects in such systems, reported previously, can easily be interpreted on the basis of the presented formalism.
Dissociation and Charge Transfer of CO2
1+ and CO2
2+ Ions in Collisions with Neutral Atoms and Molecules
Authors: Müller A. , Salzborn E.
Published: February 2015

Cross sections for single electron capture by CO2
2+ ions as well as total collision cross sections σi,tot (i=1, 2) for CO2
1+ and CO2
2+ ions in He, Ne, Ar, Kr, Xe, H2, O2, N2, CH4 and CO2 gases have been measured at 10 keV impact energy. σ2,1 varies between 4.5·10-17cm2 for the He and 1.8·10·15cm2 for the CO, target. On the average, σ2,1,tot is 1.6 times larger than σ1,tot and shows a nearly linear dependence on the gaskinetic hard sphere cross section of the target particle. The largest observed value of σ2,tot is 9.4·10-15cm2 for the CO2 target.
Collisional Depolarization of Fluorescence in the Impact and Quasistatic Limit
Authors: Behmenburg W. , Schüller F.
Published: February 2015

Collisional Depolarization of fluorescence radiation has been treated by considering the impact and the quasistatic limit of the general theory of redistribution. The result shows that a variation of the degree of polarization within the fluorescence spectrum is to be expected.
Debye Waller Factors of fee Metals by the Modified Angular Force Model
Authors: Kharoo Hira Lai , Gupta O. P. , Hemkar M. P.
Published: February 2015

A modified form of the non-central force model which takes account of the electron-ion inter­ action term of the Kreb's model in the Clark, Gazis and Wallis type angular forces is considered to calculate the Debye-Waller exponents at different temperatures for five fee metals: copper, silver, gold, aluminium and nickel. The results are compared with the available x-ray measurements in terms of the temperature parameter Y of the Debye-Waller factor, the Debye characteristic temperature ΘM and the mean square displacement of the atoms. The theoretical results are found to be in reasonably satisfactory agreement with the experimental values.
Photodetachment bei einigen zweiatomigen negativen Hydridionen: BeH–, MgH-, CaH-, ZnH-, PH-, AsH- / Photodetachment of Some Diatomic Negative Hydride Ions BeH-, MgH-, CaH-, ZnH-, PH-, AsH-
Authors: Rackwitz R. , Feldmann D. , Kaiser H. J. , Heinicke E.
Published: February 2015

The cross sections have been measured in a photon energy range between 0.5 eV and 3 eV. From threshold energies the electron affinities of the molecules have been determined.
A Molecular Dynamics Study of Aqueous Solutions VI. Remarks on the Hydration Numbers of Alkali and Halide Ions
Authors: Bopp P. , Heinzinger K. , Jancsò G.
Published: February 2015

It is proposed to define the hydration number derived from molecular dynamics simulations by the volume integral over the ion-water radial pair distribution function up to the first minimum. In order to compare such numbers with experimental results, the literature on the hydration numbers of alkali and halide ions is examined. Only the hydration numbers derived from x-ray and neutron diffraction studies are defined in a similar way and can be compared with molecular dynamics results. Considering the difficulties in deducing hydration numbers even from these two methods, the agreement might be called fair.
On Nonlocal Constitutive Relations, Continued Fraction Expansion for the Wave Vector Dependent Diffusion Coefficient
Authors: Hess Siegfried
Published: February 2015

Nonlocal constitutive relations which involve wave vector dependent transport coefficients can be derived from the Boltzmann equation. Diffusion of a Lorentzian gas is treated as an illustrative example. Transport-relaxation equations obtained from the Boltzmann equation with the help of the moment method lead to a continued fraction expansion for the wave vector dependent diffusion coefficient D(k). Rapidly converging upper and lower bounds on D(k)/D(0) are found which are meaningful for all values of lk where l is a mean free path and k is the magnitude of the wave vektor k. Also some remarks on a frequency and wave vector dependent diffusion coefficient are made.
Local Excitation as Transport Phase Transition in Phonon Systems
Authors: Kaiser Fr.
Published: February 2015

The Peierls-Boltzmann transport equation for phonons, which was re-formulated and modified in a previous paper, is extended to be applicable to arbitrary interactions and phonon processes. As a rule, it turns out that only two types of steady state solutions are possible: hysteresis and threshold. These two solutions reveal the possibility of “transport phase transitions”, i. e. a transition from the “thermodynamic” branch to a “nonthermodynamic” one via a cumulative excitation. It is shown that both the threshold and the hysteresis situation exhibit pronounced analogies to phase transi­tions in thermal equilibrium. The dependence of the steady states from the relevant parameters is discussed.
EPR and ENDOR of cubic ZnS: Mn2+
Authors: Beer R. de , Biesboer F. , Veen G. van
Published: February 2015

The spin Hamiltonian parameters of 55Mn2+ in cubic ZnS have been determined by means of EPR and central-ion ENDOR, using Ka-band (35 GHz) microwaves. For the first time a value for the spherical electric quadrupole interaction of Mn2+ incorporated in a single crystal has been found. Also the ligand hyperfine interaction and the electric quadrupole interaction of the twelve Zn67 nuclei nearest to Mn2+ have been determined by means of ligand ENDOR.
Die Temperaturabhangigkeit der elektronischen Kenngrofien des eigenleitenden Siliciums
Authors: Wasserrab Th.
Published: February 2015

From phenomenological equations for the electric resistance and the electron and hole mobilities, the intrinsic carrier concentration is calculated (ni = 1.02 · 1010 cm-3 at T = 300 K) and its temperature dependence is derived. Correlation with a well-known quantum-statistical equation delivers the temperature dependence of the density-of-states effective masses.
On the Conformational Analysis of N,N-Dimethyloxamide
Authors: Veken B. J. van der , Desseyn H. O. , Herman M. A.
Published: February 2015

The results of an energy optimization, using CNDO/2, with respect to two internal dihedral angles in N,N-dimethyloxamide are reported. The lowest minimum is found for a planar dimethylamide function, twisted around the C -C bond over an angle of 80.5 degrees with respect to the other amide function. Some calculated properties are compared with experimental data.
EEHMO-Rechnungen zur Valenzisomerisierung zwischen benzenoiden und o-chinoiden Systemen
Authors: Kolshorn Heinz , Meier Herbert
Published: February 2015

A special aspect of benzocyclobutenes and the heteroanalogous systems is the valence isomerization. which leads by ring opening to o-quinoidal structures. The energy balance of such [2π + 2σ]- reactions and the reverse [2π +2π] -cyclo-additions in the ground state S0 and in the first excited singlet state S1 are discussed. The EHT-calculation performed are based on a partial geometry optimation.
Proton Medium Effects Utilising Ferrocene Redox Couple as Reference in Propylene Glycol- Water, Methanol-Propylene Glycol and Methanol-Water Mixtures
Authors: Kalidas C. , Sivaprasad P. , Venkatram U. V.
Published: February 2015

Utilising the ferrocene reference method, proton medium effects (log mγ H+) were determined in methanol-water, pro­ pylene glycol-water and methanol-propylene glycol mixtures of varying composition. On the basis of the ferrocene meth od, it was shown that all methanol-water, propylene glycol-water and methanol-propylene glycol mixtures including the pure solvents are more basic than water and these results were explained in terms of the structural theory of ion sol­ vation proposed by Feakins and coworkers. Further, it was shown that methanol is slightly more basic than propylene glycol which is in agreement with the conclusions arrived from earlier EMF measurements.
Absorption Measurements of the Principle Series Lines of Cs Broadened by Xe
Authors: Lorenzen J. , Niemax K.
Published: February 2015

The absorption coefficients of the statistical wings of the Cs principal series lines 6 2S1/2 - n 2P3/2 (6 ≦ n ≦ 10) and 6 2S1/2 - n 2P1/2 (6 ≦ n ≦ 9) perturbed by Xe have been measured quantitatively The results are compared with quasistatic line wings calculated from the interatomic Cs -Xe potentials of Baylis 1 and Pascale and Vandeplanque 2. In the far wings of the higher lines of the series indications of many-body interaction were found. Furthermore the behaviour of the shift of all principal series lines up to the 23rd member was investigated in the density region between 1.63 X 1018 and 1.9 X 1019 Xe atoms per cm-3.
The Micro wave Spectrum of Bromoacetylene ; rs-Structure , Dipole Moment, Quadrupole Coupling Constants and Excited Vibration States
Authors: Jones H. , Sheridan J. , Stiefvater O. L.
Published: February 2015

The microwave spectrum of bromoacetylene has been investigated in the frequency range from 7 GHz to 35 GHz. From Stark effect measurements the dipole moment has been determined as μ = 0.23 + 0.01 D, and the restructure has been derived in four independent ways from twelve isotopic species: C - H = 1.0553 Å, C ≡ C = 1.2038 Å, C - Br = 1.7913 Å (internal consistency better than ± 0.0003 Å). Quadrupole coupling constants have been determined for eleven isotopic forms and are e q Q = 541.47 MHz and 648.00 MHz for HCCBr81 and HCCBr79, respectively.

Rotation spectra have also been observed for excited states of the three lowest normal modes and for several isotopic forms. For the Br81 (Br79) species the rotation-vibration coefficients are α5 = -10.98 (-11.02) MHz, α4 = -1.57 (- 1.61) MHz and α3 = + 12.88 (+ 13.40) MHz. For the bending vibrations, ν5 and ν4 , l-type doubling constants are obtained as ql5 = 4.14 (4.17) MHz and ql4 = 2.6 MHz. Analysis of the Fermi resonance between the first excited state of ν3 and the l = 0 component of the second excited state of ν5 gives the mixing ratio of these two states as a/b = 1.45 (1.51) and the interaction energy as W3,5 = 1.313 (1.181) δ3,5 for the Br81 (Br79) species. With an approximate value of δ3,5 ≌ 25 cm-1, the cubic force constant is obtained as κ3,55 ≌ 44 cm-1.

The results are discussed in relation to the molecular properties of other halogen acetylenes and halogen cyanides.