bluuebunny/crossref_metadata_2025 huggingface dataset:
ESR-, ENDOR- und TRIPLE-Untersuchungen zur Tieftemperaturkonformation von Phenoxylsystemen / Studies of the Low Temperature Conformation of Phenoxyls by ESR, ENDOR and TRIPLE-Resonance
Authors: Scheffler Klaus , Stegmann Hartmut B. , Ulrich Ch. , Schuler P.
Published: February 2015

In a series of ortho- and para-substituted phenoxyls the coupling of the β-nuclei (H and P) is caused by hyperconjugation and π-σ-mechanisms, leaving open the signs of the combined HFS constants. By examining the ENDOR and TRIPLE spectra these couplings turned out to be negative. Thus the sign of the well known temperature gradient of these parameters, due to hindered rotation of the substituted group, is positive, leading to a planar conformation of the radicals at low temperature.
The Microwave Spectrum of Excited Vibrational States of CF3NC
Authors: Christen Dines , Ramme Klaus-J.
Published: February 2015

The rotational spectra of vibrationally excited CF3NC states (ν4, ν6, ν7, ν8, 2ν8 and 3ν8) have been recorded and analyzed for the transitions J: 1→2, 2→3 and 3→4 using (for the degenerate states) a simplified frequency expression based on perturbation theory. The following vibration/rotation interaction parameters were derived (in MHz): α4: 0.145, α6: - 5.585, q+
6 4.241, α7: 2.350, q+
7: 1.438, α8: - 10.610, and q+
8: 5.101. The Coriolis constant ζÀ
88 was determined to be 0.672 in good agreement with the value calculated from the force field.
Reaction-Diffusion Dissipative Systems—Detailed Stability Analysis-Pattern of Growth and Effect of Inhomogenity
Authors: Nandapurkar P. J. , Hlavacek V. , Degreve J. , Janssen R. , Rompay P. Van
Published: February 2015

A detailed stability analysis of the one dimensional steady state solutions for the Brusselator model under the conditions of diffusion of initial (non-autocatalytic) components has been performed both for zero flux as well as fixed boundary conditions. In addition to subcritical as well as supercritical bifurcations, situations have been observed where all solution branches at a bifurcation point are unstable. A case of degenerate steady state bifurcation (2 solutions emanating from the same bifurcation point) has also been noticed. A transient simulation of the system in growth reveals the importance of growth rate on the pattern selection process and suggests that the selection of branches at a bifurcation point may be influenced by perturbations/ fluctuations. It also indicates that a stability analysis of the bifurcation diagram alone cannot decide the state of the system in a transient process, and under certain situations complex behavior may be observed at limit points.

Numerical calculations on coupled cells indicate that a heterogenity in the system can introduce multiple (two) time scales in the system. As the ratio of time scales increases, aperiodic or irregular oscillations are observed for the 'fast' variable. A combination of cells with one cell in a steady-state mode and the other in a periodic motion results in a combined motion of the entire system. For a distributed parameter system, a heterogenity can cause development of sharp local concentration gradients, alter the stability properties of steady state as well as periodic solutions and can cause partitioning of the system.
Influence of the Reversible Energy Transfer on the Donor Fluorescence Quantum Yieldin Donor-Acceptor Systems
Authors: Bojarski C.
Published: February 2015

In mixed systems of donor and acceptor molecules having closely located S1 levels a reversible nonradiative energy transfer should occur. It influences remarkably the dependence of the donor quantum yield ηD on the acceptor concentration in the range of high acceptor concentrations of systems with high donor-to-acceptor reduced concentration ratios.
Determination of Dipole Moments by Microwave Fourier Transform Spectroscopy. Trifluoropropine, Tert.Butylisocyanide, and Cvanoacetylene
Authors: Kasten W. , Dreizler H.
Published: February 2015

We report the measurements of dipole moments by Microwave Fourier Transform Spectroscopy. Hereby we indicate that it is worth to supplement this type of microwave spectroscopy to increase its capability.
An Improved Variational Calculation of the Lower Vibrational Energy Levels of the Ammonia Molecule
Authors: Maessen Bärbel , Bopp Philippe , McLaughlin Don R. , Wolfsberg Max
Published: February 2015

A new variational calculation of the inversion spectrum of ammonia is reported in which all six vibrational degrees of ammonia are employed. By fitting spectroscopic data, an inversion barrier of 1810 cm-1 is obtained.
Asymptotic Solution Near Focus of a Two-dimensional Shock and Instability Near Axis of a Cylindrical Shock with CCW Approach
Authors: Yu Shanbing
Published: February 2015

The Chester-Chisnell-Whitham equations in Cartesian and polar coordinates are written out for the two-dimensional case. The solution expanded near a point is obtained. The asymptotic solutions of order 2 near focus are presented. Linear small perturbation analysis for a converging cylindrical shock is given. To study the development of perturbations numerical solutions are carried out.
Self-Consistent Density Functional Approach to a Metal/Electrolyte Solution Interface
Authors: Kornyshev A. A. , Partenskii M. B. , Schmickler W.
Published: February 2015

Two models for a plane interface between a free electron metal and a concentrated solution of a surface inactive electrolyte are treated fully self-consistently, taking into account both the polarizability of the metallic electron cloud and the reorientation of solvent molecules. The interfacial capacity is calculated as a function of the electrode charge, and its dependence on various system parameters is investigated. Some conclusions on the structure of the interface are drawn from a comparison between our results and experimentally observed trends.
The β+ Decay of 234Np and Other Isospin-Forbidden 0+→ 0+ Fermi Transitions
Authors: Yap C. T. , Saw E. L.
Published: February 2015

Although experimental values of the Fermi nuclear matrix elements vary widely from about 1 × 10-3 to 40 × 10-3 for isospin-forbidden 0+→0+ β transitions, theoretical calculations using the Coulomb potential and Nilsson wave functions yielded values of MF in reasonably good agreement, except that of 234Np. However, our calculation of MF for this decay as a function of the deformation parameter β yielded a value of MF in good agreement with experiment for values of β between 0.1 and 0.2.
Theoretical Determination of the Ground State Geometry of 1.3.5-Triphenylbenzene
Authors: Ciosłowski J.
Published: February 2015

The geometry and electronic structure of 1.3.5-triphenylbenzene (TPB) has been determined by semiempirical quantum methods. Using the MNDO approach, the salient dependencies of the first ionization potential, the intramolecular distances and the bond angles on the dihedral angle between the planes of the TPB benzene rings were established. By an application of the CNDO/S method the UV spectrum of TPB was calculated. A comparison of the calculated transition energies with the values observed in the absorption spectrum yields 45° for the dihedral angle, which is in reasonable agreement with the available experimental data.
Über topologische Räume, welche kovalenten Verbindungen zugeordnet werden können, und ihre Bedeutung für die Chemie
Authors: Polansky Oskar E.
Published: February 2015

Using Hausdorff’s neighbourhood axioms, topological spaces associated with molecular graphs are derived. Their meaning for chemistry is illustrated by topological charge stabilization and the topological effect on MO (TEMO). Finally the role of molecular topology with regard to chemical structure is discussed.
Tetrahedral XY4 Molecules: Application of the Keating Bendings to the Degenerate Vibrations
Authors: Cyvin S. J. , Cyvin B. N. , Einarsrud M.-A. , Brunvoll J. , Fleming G. Díaz
Published: February 2015

The Keating force field of tetrahedral XY4 molecules is defined in analogy with valence and central force fields. The applicability of the Keating coordinates versus valence and central coordinates is tested by different approaches. The general conclusion goes in favour of the Keating coordinates.
Electron Paramagnetic Resonance of Ni2+ in BaZnF4 Single Crystals
Authors: Remme S. , Lehmann G. , Recker K. , Wallrafen F.
Published: February 2015

X-band EPR measurements of Ni-doped BaZnF4 crystals revealed presence of three centers. Well-resolved hyperfine structure from 19F nuclei at suitable orientations allowed assignment of the most intense spectrum to single ions on Ba sites. The occupation of Zn sites is considerably lower. The third spectrum is assigned to pairs of Ni2+ ions on adjacent Ba sites. Attempts to correlate the zero-field splitting (ZFS) patterns of the single ion spectra with the distortions of the first coordination spheres of Ba and Zn resp. with a single intrinsic ZFS parameter for both bridging and nonbridging ligands were equally unsuccessful as in the case of Mn2+.
Substitution Structures of Gauche and Trans Isobutyraldehyde by Double Resonance Modulation Microwave Spectroscopy
Authors: Stiefvater O. L.
Published: February 2015

Nine isotopic species of gauche- and seven isotopic forms of rra«.s-isobutyraldehyde, (CH3)2CHCHO, have been studied by DRM microwave spectroscopy to determine dihedral angles within and between the two rotameric conformations. In the gauche conformation one methyl group (subscript 3) eclipses the oxygen atom exactly, and best compatibility with the isotopic data is obtained when the two carbon-to-methyl bonds are assumed to be of equal length. The isotopic data for the less stable trans rotamer do not allow unequivocal determination of the bondlengths in the isobutyl skeleton, but bond angles and dihedral angles are determined satisfactorily. For both rotamers the geometry of the methyl groups was assumed with C - H = 1.088 Å and ∠ CCH = 110.2°.

The following bondlenghts (in Å) and angles (in degrees) are best compatible with the isotopic data:

[xxx]

The structural differences between the two rotamers are explained as due to repulsion between the bonds at either end of the rotameric axis.
Quantenchemische Rechnungen an Stickstoffbasen. Teil 4*: Zur Berechnung der Polarisierbarkeiten aliphatischer Amine mit der MINDO /3-FP-Methode
Authors: Niephaus Herbert , Raabe Gerhard , Fleischhauer Jörg
Published: February 2015

The polarizabilities of some primary, secondary, and tertiary amines have been calculated with the MINDO/3-FP-method. The calculated values are found to correlate with the experimental polarizabilities and with those determined by the method of Miller and Savchik in a satisfying manner. In addition atomic polarizabilities have been calculated according to the method of Metzger. Averaging over the calculated mean atomic polarizabilities of hydrogen, carbon, and nitrogen yields increments which, when used to recalculate molecular polarizabilities, lead to values which correlate in an excellent manner with those determined from densities and refraction indices by means of the Lorenz-Lorentz-equation.

Because different nitrogen increments have been determined for primary, secondary and tertiary amines, the parameters presented here make it possible to distinguish between constitutional isomers as long as they belong to different groups (i.e. primary, secondary, and tertiary amines), something which cannot be done using the method of Miller and Savchik. The increments derived do not only allow to predict the polarizabilities of primary, secondary and tertiary amines but can be used to calculate the corresponding values for hydrazines and polyfunctional amines with equal success.
Convective Instabilities and Dynamic Structures in Phase-Separation Processes of Binary Liquid Mixtures
Authors: Dittmann Michael , Schneider Gerhard M.
Published: February 2015

In pressure jump experiments on the phase separation of binary liquid mixtures of cyclohexane + methanol, an organisation of the finely dispersed precipitate could be observed to give a macroscopic dissipative structure during the early stages of the ageing process of the newly formed phase. Preliminary phenomenological investigations suggest a mechanism similar to the Rayleigh-Benard instability (RBI) and the Soret-driven instability (SDI).
Theory of NMR Shifts and ENDOR Spectroscopy in Paramagnetic ln Complexes
Authors: Eicher H.
Published: February 2015

The interactions of magnetic hyperfine spectroscopy are expressed in irreducible tensoroperator form, suitable for applications to configurations ln with n equivalent electrons outside closed shells. The matrix elements are evaluated on the basis of Racah’s techniques. The familiar point-dipole approximation of the pseudocontact interaction is valid for n ≦ 2l + 1; a minus sign, however, must be introduced in this formula for n > 2l + 1.
The Microwave Q-branch Spectrum of Germane in the Vibrational Ground State
Authors: Stahl W. , Dreizler H. , Jörissen L. , Kreiner W. A.
Published: February 2015

We present an analysis of the rotational spectra of 70GeH4, 72GeH4 and 74GeH4 in the vibrational ground state measured by microwave Fourier transform (MWFT) spectroscopy. All quartic, sextic and octic tensor centrifugal distortion constants have been determined. A discussion of spin-rotation and spin-spin interactions will be given in a subsequent paper.
The Crystal and Mesophase Structure of Hexakis(alkylsulfono)- benzene Homologues by X-Ray Diffractometry
Authors: Spielberg N. , Luz Z. , Poupko R. , Praefcke K. , Kohne B. , Pickardt J. , Horn K.
Published: February 2015

A powder X-ray diffractometer study of hexakis(tridecylsulfono)benzene (HASB13) has been carried out over the temperature range 20 to above 80 °C. In this range three phase transitions are observed by sharp discontinuities in the diffraction pattern indicating a solid-solid, solidmesophase, and mesophase-liquid transition. The mesomorphic phase is identified as a hexagonal columnar discotic mesophase, Dhd, with intercolumnar spacing of 25.7 Å and average stacking distance of 4.9 Å. Both distances are independent of temperature but there appears to be a gradual increase in the stacking disorder as the temperature is increased. The magnitude of the intercolumnar distance suggests a considerable degree of side chain disorder. A detailed X-ray diffraction study was also performed at room temperature on a single crystal of hexakis(propylsulfono) benzene (HASB3), which is not mesogenic. The results provide detailed information on the structure of HASB 3 which is used in the interpretation of HASB 13 results.
Axisymmetric Plasma Equilibria with Incompressible Flow
Authors: Elsässer Klaus , Heimsoth Alfred
Published: February 2015

The reduction of the ideal MHD equations to a scalar elliptic equation (“ζ-equation”) is discussed for an axisymmetric equilibrium with an incompressible subcritical flow field. First it is shown that the most general equilibrium of this type can be obtained by a numerical solution for the case of a purely toroidal motion (“isorotation”); it is defined by prescribing three flux functions. Then a gauge transformation ζ(Ψ) corresponding to a re-labeling of the flux surfaces (which are kept fixed) allows one to introduce a finite subcritical poloidal flow which minimizes the total energy content. Finally a nonlinear analytical model problem is used to test the efficiency of a numerical procedure for solving the ζ-equation; fast convergence and good results are obtained with a Newton-type iteration which has been discretized by the finite element method.
Determination of a High Potential Barrier Hindering Internal Rotation from the Microwave Ground State Spectrum The Methylbarrier of Antiperiplanar and Synclinal Normal Propyl Fluoride
Authors: Kasten W. , Dreizler H.
Published: February 2015

The microwave ground state spectra of antiperiplanar and synclinal normal propyl fluoride have been measured by microwave Fourier transform spectroscopy and analysed for methyl torsion fine structure. Additionally, the spectrum of the synclinal form in the first excited state of the methyl group has been investigated due to methyl torsion. The difference of the values determined for the barrier heights in the ground and first excited state of the synclinal form is discussed by an approximate treatment of the coupling of CH3 and C - C torsional motions.

As high J transitions were measured a centrifugal distortion analysis was necessary.
The Fourier Transform IR Spectra of CIF and BrF
Authors: Bürger H. , Jacob E. , Fähnle M.
Published: February 2015

Fourier transform infrared spectra of C1F and BrF have been measured with a resolution of 0.04 cm-1 in the region of the fundamental and First overtone with an accuracy of 2 and 4 x 10-3 cm-1, respectively. The rotational structure was resolved up to J" = 58/62 (ClF/BrF), and υo values have been obtained from rotational analyses o f the υ 1 ← 0, 2 ← 1, 2 ← 0 and. in part, 3 ← 1 and 3 ← 0 vibrational bands. These have been employed to obtain the hitherto most accurate ωe, ωeχe and (for C1F) ωeγe values. From the rotational analyses, Be, αe, γe, De and ße have been derived.
Maxwell-Dirac-Isomorphism. XI
Authors: Sallhofer Hans
Published: February 2015

Maxwell-Dirac-isomorphism and economy of science.
A Capillary Discharge for Determination of Plasmadiagnostically Relevant Atomic Quantities
Authors: Neger T. , Jäger H.
Published: February 2015

An improved capillary discharge technique renders possible the production of a plasma jet representing a radially symmetric LTE light source. It shows a special capability of producing plasmas of elements or compounds which exist in the solid state under normal conditions. This plasma source is also suited for the investigation of emission lines of ionised atoms. To demonstrate a possible application, relative transition probabilities of some prominent Cullines in the visible are determined and compared with results of other authors.
Entropy Production in a Chaotic Chemical System
Authors: Lindgren Kristian , Månsson Bengt Å . G.
Published: February 2015

The average rate of entropy production in a homogenous chemical system is investigated in oscillating periodic and chaotic modes as well as in coexisting stationary states. The simulations are based on an abstract model of a chemical reaction system with three freely varying concentrations. Five concentrations are assumed to be kept constant by suitable flows across the boundary. A fixed concentration is used as a control parameter. Second order mass action kinetics with reverse reaction is used. An unexpected result is that periodic modes in some windows in the chaotic interval have higher average rate of entropy production than the surrounding chaotic modes. A chaotic mode coexists with a stable stationary state with smaller entropy production. A unique (unstable) stationary state produces more entropy than the corresponding oscillating mode.
Fifty Years of Nuclear Quadrupole Moments
Authors: Brix Peter
Published: February 2015

On March 2, 1935 Hermann Schiller and Theodor Schmidt reported the first experimental evidence of non-spherical nuclei. From careful hyperfine structure studies of several Eu I-lines, they had shown that the hyperfine components of 151Eu and 153Eu did not follow the Lande interval rule exactly. Since the deviations were larger for 153Eu with the smaller magnetic moment, level perturbations were ruled out. This led to the conclusion of nuclear quadrupole moments. The theory was published June 1, 1935 by Hendrik B. G. Casimir. Nuclear deformations are playing a decisive role in modern nuclear structure physics. For solid state physics, spectroscopic quadrupole moments are very useful, since they probe the electric field gradient at the nuclei.

This review presents the discovery of 1935 in historical context: 1. Early measurements of nuclear radii. 2. Discovery of nuclear quadrupole moments. 3. Spectroscopic quadrupole moments (absolute measurements; relative hyperfine data, europium revisited). 4. Intrinsic quadrupole moments (discovery from isotope shifts; present status, samarium revisited). 5. Charge distribution of deformed nuclei.
The Quadrupole Moments of the Stable Nuclei of Sulphur and Chlorine
Authors: Elbel M. , Quad R.
Published: February 2015

By means of collinear laser spectroscopy the hyperfine structure of two transitions in the ionic spectra of sulphur and chlorine has been measured. The hyperfine constants of the involved levels have been determined. From them and by means of the spin-orbit coupling constants of the involved p-electrons the quadrupole moments of 33S, 35Cl and 37Cl could be determined anew. The importance of the new values is seen in the fact that in the case of sulphur they result from measurements at the free ion or, in the case of chlorine, that they result from an electron other than 3 p.
Electric Field Gradient at 99Ru in Dilute Silver Alloys
Authors: Królas K. , Boise W. , Ziegeler L.
Published: February 2015

The quadrupolar coupling between

the charge perturbation around fifth-row impurities (Cd, In, Sn and Sb) in silver has been investigated
employing the perturbed angular correlation technique. A considerable fraction of probe
nuclei is exposed to a unique electric field gradient which is attributed to the nearest neighbour
probe-impurity configuration resulting from an attractive interaction. The quadrupole coupling
constant increases with impurity valency. A comparison of the present results with those obtained
with 100Rh nuclear probe indicates that a large probe-dependent contribution to the electric field
gradient occurs, which is not related to the lattice strain induced by both probe and impurity
atoms.
Crystal Structure and Single Crystal 35Cl NQR of 1,2-Dichloro-3-Nitrobenzene, Cl(1)Cl(2)(NO2)(3)C6H3
Authors: Sharma Surendra , Paulus Helmut , Weiden Norbert , Weiss Alarich
Published: February 2015

and single crystal

l,2-Dichloro-3-nitrobenzene, Cl(1)Cl(2)(NO2)(3)C6H3, was investigated by X-ray diffraction 35Cl NQR Zeeman spectroscopy. The crystal structure was determined, RW = 0.033. The compound crystallizes with the space group C2h
5
- P21/c, Z = 4; a = 381.0(1) pm, b = 1376.5(3) pm, c = 1430.2(3) pm, β = 97.764(5)°. From the
35Cl NQR Zeeman spectra it was found at 294 K: e2ΦzzQh-1 (
35Cl(1)) = 71.892(6) MHz, η(35Cl(1)) = 0.1287(25), e2ΦzzQh-1 (35Cl(2)) = 75.436(6) MHz, η(
35Cl(2)) = 0.1525(25). The angles (Φzz
(1),Φzz
(2)) and (Φzz
(2), C(3)-N(3)) are slightly opened in comparison to the corresponding X-ray bond angles. The temperature
dependence of ν(
35Cl) is reported.
Zeeman NQR Powder Line Shapes for Half Integral Spin Nuclei
Authors: Bryant P. J. , Hacobian S.
Published: February 2015

A polycrystalline material was simulated by assuming a random distribution of small

crystalites. The effect of a small applied magnetic field on the NQR lineshape was calculated for
half integral spin nuclei ( I = 3/2, 5/2, 7/2 and 9/2) using a theory based on Toyama’s work [11],
The line shapes indicate qualitatively the half width ratios o f the upper and lower resonances
(e.g. Δν2/ Δν1] for I = 5/2 ) and thus enables one to see generally whether the broadening
mechanism is mainly due to magnetic or electric effects.
14N Nuclear Quadrupole Coupling — Correlation of Experimental and Theoretical Values with Structure
Authors: Palmer Michael H.
Published: February 2015

Ab initio calculations, generally of triple zeta + polarisation quality, and sometimes with

configuration interaction and iterative natural orbitals, are reported for a number of N-F, N-Cl
and N-O bonded molecules. Evaluation of the electric field gradients (EFG) generally gives a
good account of microwave inertial axis data, which can then be extended to the EFG principal
axis data.
19F Nuclear Quadrupole Coupling in some Halomethanes
Authors: Frank M. , Gubitz F. , Ittner W. , Kreische W. , Labahn A. , Röseler B. , Weeske G.
Published: February 2015

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.
The Electronic Structure of Borazine as seen by 10B, 11B, and 14N Nuclear Quadrupole Double Resonance
Authors: Lötz A. , Voitländer J. , Smith J. A. S.
Published: February 2015

The nitrogen nuclear quadrupole coupling in borazine is reported and interpreted in combination with the previously measured boron coupling. A novel Townes-Dailey type of analysis was employed to obtain the electron distribution in borazine. A calculated π-donation of ~ 0.5 e from the nitrogen atom to the vacant π-orbital of boron is accompanied by a strong polarisation of the σ-skeleton, imparting a negative charge to nitrogen and a positive charge to boron.
The Complex between Chloromethane and Benzene
Authors: Rupp Daniel , Lucken Edwin A. C.
Published: February 2015

35Cl Nuclear Quadrupole Resonance, NQR, spectra of mixtures of Chloromethane and Benzene, with relative molar compositions in the range 1:3 to 3:1, and at temperatures in the range 77 K to 180 K, reveals the presence of a new crystalline phase, in addition to that of pure Chloromethane. The temperature-dependence and the deuterium isotope effect of this new resonance show that the chloromethane molecule is much more labile in the new crystalline phase than in pure chloromethane. The existence of the new crystalline phase is confirmed by Differential Thermal Approach, DTA, which in addition provides evidence that the complex has a 1:1 composition and that the enthalpy of fusion is ≈ 660 cal./mole. Raman spectroscopy provides further evidence of the existence of the complex.
Nuclear Quadrupole Resonance Studies on Molecular Complexes
Authors: Basu Rama
Published: February 2015

NQR studies of a number of molecular complexes with p-chloronitrobenzene and o-chloronitrobenzene as acceptors and different hydrocarbons as donors were carried out. A linear relationship between the NQR shift and the ionization potentials o f the donors is obtained. Maksyutin’s idea o f a positive shift with respect to acceptors having a quadrupolar nucleus is shown to hold in those systems. Townes and Dailey’s method was applied to calculate the change in the ionicity of the C - Cl bond on complexation to account for the σ-electronic contributions in the systems.
17O NQR and the Mechanism of the Phase Transition in KH2PO4 Type H-bonded Systems
Authors: Blinc R.
Published: February 2015

17O quadrupole and 17O-proton magnetic dipolar coupling data are used to discriminate between three alternative phase transition driving mechanisms in KH2PO4 type H-bonded systems: (i) the proton order-disorder model; (ii) the P (or Se) ion order-disorder model, and (iii) the PO4 (or SeO3) orientational order-disorder model.The data for KH3(SeO3)2, CsH2PO4 and KH2PO4 definitely exclude models (ii) and (iii) and agree with the predictions of model (i).
A Phase Transition and Molecular Dynamics in Crystalline C6H5CHCI2 by 35Cl NQR Investigations
Authors: Kjuntsel I. A. , Mokeeva V. A. , Soifer G. B. , Shaposhnikov I. G.
Published: February 2015

The NQR frequency ν and the spin-lattice relaxation time T1 of 35Cl nuclei in crystalline (ω,ω)-dichlorotoluene, C6H5CHCl2, have been measured at temperatures above 77 K. The existence of a second-order phase transition was discovered at Tc = 94 K. At this point the low-temperature NQR spectrum consisting of five lines passes into the high-temperature doublet. The behaviour of ν and T1 as functions of temperature near the critical point Tc is investigated and corresponding parameters are obtained. The NQR signals fade out about 185 K due to the reorientational motion with the potential barrier of 33.9 kJ/mole.
The Proton Motion Effect in the Ferroelectric Phase of NH4H(ClCH2COO)2
Authors: Zdanowska-Fraczek Maria
Published: February 2015

The effects of pressure up to 3 · 102 MPa on the 35Cl NQR line splitting in the ferroelectric phase of NH4H(ClCH2COO), was studied from 77 K to Tc. The results are interpreted in terms of the so called pseudo-spin-lattice coupled mode model. A correlation was found between the magnitude of the 35Cl NQR line splitting and the pseudo-spin component  (the order parameter of the applied model).
Isotope Shifts in Ammonium Perrhenate
Authors: Haslett T. L. , Brown R. J. C. , Park Y. S. , Shurvell H. F.
Published: February 2015

Isotope shifts in the NQR and Raman spectra o f ammonium perrhenate due to 15H and 2H substitution are reported. The effect of isotopic substitution at the nitrogen on the NQR spectrum is zero; in the Raman spectrum the translational lattice modes of the ammonium ion are clearly differentiated from the torsional modes.

The effect of deuteration on the NQR frequency has been measured to high accuracy and confirms that to a moderately good approximation the effect of deuteration is equivalent to the application of pressure. The effect of deuteration on the lattice parameters has been measured. NQR spectra of slightly deuterated ammonium perrhenate show a shoulder with a characteristic shift due to short range influence of NH3D+.
Symmetry Partitioning over Liouville Space for Evolution under the Anisotropic Quadrupolar Spin-Spin Interaction
Authors: Temme F. P. , Sanctuary B. C.
Published: February 2015

The structure of the anisotropic indirect quadrupolar spin-spin interaction, and its effect on the spin dynamics associated with pure NQR time-domain response, is considered in terms of spherical tensor operator bases and multipole theory. The advantages of symmetry-adapting the Liouville bases is discussed for I ≧ 3/2 spin systems.

In particular, symmetrized state space bases for the n-fold quadrupole cluster under Sn are introduced and enumerated for I = 3 /2 and n ≦ 4, as an initial step in the process. Symmetrized Liouville space bases for the [A]2 problems involving [3/2 :3/2] and [5/2:5/2] spin pairs under the group S2 are presented to illustrate the structure of the multipole calculations of the spin evolution under the specific spin-spin interaction term. Such systems are of especial interest on account of the nature of the molecular solids Br2 and I2.
Relaxation Processes in NQR Multiple-Pulse Spin-Locking
Authors: Ainbinder N. E. , Furman G. B. , Kibrik G. E. , Poljakov A. Yu. , Shaposhnikov I. G.
Published: February 2015

A theory of the spin-lattice and spin-spin relaxation processes in quadrupole spin systems with I > 1/2 in the situation of the multiple-pulse NQR spin locking is proposed for the pulse sequence MW-4. The theory is based on the assumption that for t ≳ T2 the change of the spin system is a quasi-equilibrium process. Rate equations for inverse generalized temperatures are obtained and the kinetic coefficients calculated for the case o f exponential correlation functions. The above assumption was confirmed for some substances containing the 35Cl and 123Sb, and the time constant T1e characterizing the spin echo signal decay was investigated and compared with the time constant T1q, in the case of continuous spin locking.
The Effect of Lattice Vacancies on the NQR Parameters
Authors: Martin Carlos A. , Zuriaga Mariano J.
Published: February 2015

Lattice vacancy effects on NQR parameters such as the transition frequency (νQ), the spin lattice relaxation time (T1), and the linewidth (Δν) are studied, and expressions are proposed to describe their temperature behaviour. These expressions are applied to analyse the case of solid chlorine and values are derived for the energy and entropy associated with the creation of a vacancy and its migration energy.
Delayed Double Resonance Between Quadrupolar Levels: Observation of a Nuclear Spin Emission Signal in s-Triazine
Authors: Manallah B.
Published: February 2015

A delayed double resonance experiment was carried out using a Robinson-type continuous wave spectrometer. The sample chosen was s-triazine at liquid helium temperature, where the relaxation times are of the order of ten hours. Line pairings between the two Nitrogen-14 NQR sites were confirmed. Emission signals from ν- transitions were observed after successively saturating first the ν- line and then the ν+ line. The results are understood in terms of a simple model of spin population dynamics.
Quadrupole Effects in 14N and 2D Ligand ENDOR Studies of a Bis(glycinato)-Cu(II) Complex in Triglycine Sulfate Single Crystals
Authors: Böttcher R. , Windsch W.
Published: February 2015

The analysis of the 14N and 2D quadrupole interactions in the bis(glycinato)-Cu(II) complex in triglycine sulfate single crystals reveals the efficiency of the ENDOR method. In both cases the complete quadrupole tensors are measured and analyzed. The 14N quadrupole couplings are explained using the Townes-Dailey approach to obtain the electronic population near the nitrogens. Using the well known relationship between the 2D couplings and the N-D bond lengths as well as the fact that the axis corresponding to the tensor component of largest magnitude lies along the N-D bond, the position of the deuterons in this Cu(II) complex is estimated.
Time Domain Zero Field NMR and NQR
Authors: Bielecki A. , Zax D. B. , Thayer A. M. , Millar J. M. , Pines A.
Published: February 2015

Field cycling methods are described for the time domain measurement of nuclear quadrupolar and dipolar spectra in zero applied field. Since these techniques do not involve irradiation in zero field, they offer significant advantages in terms of resolution, sensitivity at low frequency, and the accessible range of spin lattice relaxation times. Sample data are shown which illustrate the high sensitivity and resolution attainable. Comparison is made to other field cycling methods, and an outline of basic instrumental requirements is given.
Some Reductive Methods for Nonlinear Waves in an Elastic Cylinder and a Channel Containing a Two-Layer Fluid
Authors: Murawski K.
Published: February 2015

A nonlinear wave theory is developed to review the reductive Taniuti-Wei, the derivative expansion, and the rays methods. Model equations describing wave propagation in a fluid-filled cylinder with a thin wall of elastic rings and a channel containing a two-layer fluid are derived via these methods.
A Crucial Test for Einstein’s Special Theory of Relativity Against the Lorentz-Poincaré Ether Theory of Relativity
Authors: Winterberg F.
Published: February 2015

A crucial experiment is proposed which should decide between Einstein’s interpretation of the Lorentz transformations, where the relativistic effects are explained as the result of space-time transformations, and the alternative interpretation by Lorentz and Poincare, where all the same effects are explained by real physical deformations of bodies in absolute motion through an ether. To break the interaction symmetry with the ether, suitable experiments must involve rapid rotation to violate the relativistic Born rigid body motion criterion. However, if the body-deformation is governed by regular elastic waves, relativity-violating effects are very small with attainable rotational velocities and are therefore probably unobservable. An exceptional situation exists if the deformation is governed by bending waves. In this case, relativity-violating effects would manifest themselves by a very large resonance, greatly amplifying an otherwise minute effect.
Notizen: Maxwell-Dirac-isomorphism, XII
Authors: Sallhofer Hans
Published: February 2015

Maxwell-Dirac-isomorphism and spinor calculus.
Quantumchemical Calculations on Nitrogen Bases. Part 6 *: Analysis of the Proton Affinities of Aliphatic Amines Using the Kitaura-Morokuma Scheme and the MINDO/3 Method
Authors: Raabe Gerhard , Fleischhauer Jörg
Published: February 2015

The energy partitioning scheme of Morokuma et al. has been applied to the proton affinities of fourteen aliphatic amines. The electrostatic, the polarization and the charge transfer component of the proton affinities have been calculated using the MINDO/3 method. Two different sets of structural parameters have been used for the complexes of the bases and the attacking proton. Within the framework of the semiempirical method employed here, the electrostatic interaction between an attacking proton and the base was found to be positive as a result of the relative magnitudes of the repulsion terms used in the proton-electron and the proton-core interactions.

In the case of the polarization term our findings roughly parallel those of Morokuma. For one of the two sets of structural parameters a good and almost group overlapping correlation was found between polarization energies and experimental proton affinities: the polarization part was found to decrease with increasing proton affinity. Independent of the choice of the amine geometries, the results for the charge transfer energy contradict the nonempirical data of Morokuma: Contrarily to his results we found values which increase in the order ammonia < methylamine < dimethylamine < trimethylamine.
MINDO-Forces Study of Methyl Substituted Allyl Cations
Authors: Jarjis Hayfa M. , Khalil Salim M.
Published: February 2015

MINDO-Forces calculations have been performed on methyl substituted allyl cations with complete energy minimization. It was found that the methyl substitution on the terminal carbon atoms of the allyl cation stabilizes the cation more than that at the center carbon atom. Also, the stability of the cation depends on the conformation of the cation and not on the number of methyl substituents.
Indefinite Metric and Positive Probabilities
Authors: Just K. , Narramore P.
Published: February 2015

We propose a bound on the mass of every state preparable in particle physics. Thus a realistic cutoff can be permitted although it implies an indefinite metric.
Molecular Motion in Solid Tetrabutylammonium Iodide
Authors: Szafrańska Barbara , Pająk Zdzisław
Published: February 2015

The temperature dependence of the 1H second moment and the T1 and T1ϱ spin-lattice relaxation times obtained for polycrystalline tetrabutylammonium iodide are interpreted in terms of the C3 methyl group reorientation appearing together with cationic tumbling for which the activation parameters have been determined. IR spectra point to the existence of weak C - H . . . I hydrogen bonds. A structural phase transition evidenced at about 386 K is found to be related to the onset of cationic self-diffusion.
Paramagnetic Resonance of Fe3+ in CdGa2Se4 Crystals
Authors: Siebert D. , Febbraro S.
Published: February 2015

Fe3+ may serve as a substitutional spin probe to characterize the two different Ga sites in CdGa2Se4. Unusually high tilting angles are found for the Fe3+ centers and indicate the limits for applying the spin probe technique.
Charge Transfer Complexes of N-Arylcarbamates with π-Acceptors
Authors: Mourad Aboul-fetouh E.
Published: February 2015

The charge-transfer (CT) complexes of some N-arylcarbamates as donors with a number of π-acceptors have been studied spectrophotometrically. The Lewis basicities of the N-arylcarbamates as well as the types of interactions are discussed. The 1H-NMR spectra of some CT complexes with both 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) and 7,7,8,8 tetracyanoquinodimethane (TCNQ) indicate a decrease of the electron density on the donor part of the complex.
A Note on the 14N Electric Field Gradient Notizen: Tensors in Incommensurate [N(CH3)4]2ZnCl4
Authors: Dolinšek J. , Blinc R.
Published: February 2015

The 14N electric field gradient tensors of [N(CH3)4]2ZnCl4 have been re-determined in the paraelectric phase at 26 °C and in the incommensurate phase at 16 °C. The results in the incommensurate phase show the “non-local” nature of the 14N EFG tensor interaction.
Synergetics, Selfsimilarity and Computergraphics
Authors: Fuchs Armin
Published: February 2015

Selfsimilarity as an intrinsic symmetry of complex dynamical systems is demonstrated using several iteration procedures e.g. time-iteration of discrete maps as well as iterations in space leading to péano curves.
Stark Widths of Cul and Cull Lines
Authors: Neger T. , Jäger H.
Published: February 2015

Half widths of 6 Cul and 3 Cull lines have been measured using a plasma jet generated by a modified capillary discharge technique. The presented values are normalized for an electron density of 1.1017 cm-3 and a temperature of 20 000 K and are compared with results of other investigations.
Comparative Study of the Reactions of 16OH and 18OH with H16O2.
Authors: Dransfeld P. , Wagner H. Gg.
Published: February 2015

The gas phase reactions

18OH + H16O2 → H2
18O + 16O2 (1a)

18OH + H16O2 → 16OH + H18O16O (1b)

were studied at room temperature in a discharge flow reactor with far infrared laser magnetic resonance (LMR) detection of 16OH, 18OH and H16O16O. The formation of 16OH in the course of the reaction was observed. The absolute rate constant for the overall removal of 18OH in excess of H16O16O was determined. Each run was accompanied by a control experiment replacing the initial 18OH by the same amount of 16OH. From these experiments a branching ratio is obtained of

k1a/( k1a + k1b) = 0.52 ± 0.08
Raman-Spektren des Calcium und Barium-ortho-Thiophosphates
Authors: Brückner Wolfgang , Pätzmann Ulrich
Published: February 2015

The ortho-Thiophosphates Ca3(PS4)2 and Ba3(PS4)2 have been prepared and their Raman spectra recorded. The observed frequencies of the title compounds are assigned on the basis of tetrahedral PS4
3- units (Td symmetry).

The formation of ortho-Thiophosphates with cations in the oxidation state 2(Me3
II(PS4)2) is quite uncommon.
Characterization of the Phenanthrene-Tetrachlorophthalic Anhydride (P/TCPA) 1:1 Charge-Transfer Crystal: Spectroscopic and Structural Investigations
Authors: Krzystek J. , Schütz J. U. von , Wolf H. C , Stigler R.-D. , Stezowski J. J.
Published: February 2015

The 1:1 phenanthrene-tetrachlorophthalic anhydride (P/TCPA) charge-transfer complex crystalizes with monoclinic symmetry, space group P21, with two magnetically inequivalent stacks in the unit cell. The noncentrosymmetric space group is very unusual for CT-complexes. The optical emission spectra at low temperature are characterized by a strong CT phosphorescence and a weak CT fluorescence and delayed fluorescence.

The S1 band lies at 22 800 ± 100 cm-1, the T1 band at 21 200 ± 100 cm-1. Above 15 K triplet excitons, moving along the stacks are revealed by ESR. They have a CT character of about 30%, coinciding with that of the shallow X-traps found by ODMR at low temperatures. A further trap, with zero-field-splitting (zfs) parameters of D = ± 0.0617, E = + 0.0116 cm-1 has a much larger CT character of 50% as found in the isolated complex in low-temperature glass [1]. A structural model is proposed.
Zur spektroskopischen Analyse von Assoziationsgleichgewichten am Beispiel Eosin
Authors: Polster J.
Published: February 2015

By means of absorbance diagrams dimer equilibria 2B ⇄ C can be analysed by nonlinear regression. As an example, the procedure is demonstrated for the association of eosin.
The Isotope Effect of Li+ Ions in Electromigration of Molten LiNO3
Authors: Endohand Akira , Okada Isao , Nomura Masao , Okamoto Makoto
Published: February 2015

The relative difference in internal mobilities o f 6Li and 7Li, ε, in molten LiNO3 has been remeasured in the temperature range from 559 K to 726 K by countercurrent electromigration (Klemm 's method). As temperature increases, the isotope effect increases, although the increasing rate decreases: it is practically constant above 650 K. The ε values are lower than those measured by Lundén and Ekhed [5] by 15-25% . The effective diffusion coefficients have been estimated from the distribution of the isotopes in the separation tube by numerical simulation.
Hall Effect, or Hyperbolic Magnetohydrodynamics, HMHD
Authors: Witalis E. A
Published: February 2015

The MHD theory of present magnetic fusion research is briefly reviewed with emphasis on its mathematically diffusive character. The importance of retaining the Hall effect term, neglected in ideal or resistive MHD theory, is stressed. Elliptic MHD theory is critically dismissed. The Hall effect, or Hyperbolic, MagnetoHydro-Dynamics, HMHD, is shown to follow as the consequence of a revision of plasma electrodynamics so as to account for the fundamental plasma quasineutrality. The non-validity of Newton’s third law in charged particle contexts is then central. Previously poorly understood phenomena, such as plasma edge effects and magnetic field line reconnection are found to be inherent properties in this HMHD plasma description. The “magnetic bottle” principle for high density plasma confinement is shown to be physically unsound because there will exist a no-confinement plasma boundary region with HMHD theory properties. Arguments for non-thermal fusion, provided by HMHD theory, are given.
Some Asymptotic Results in Turbulent Diffusion
Authors: Gräff Pitter
Published: February 2015

The frozen-in case of turbulent diffusion requires for certain stochastic monotonic functions, for which a central limit theorem holds.
Nonlinear Evolution of the m = n = 1 Kink-Mode in a Periodic z-Pinch
Authors: Kratzsch K. A. , Rebhan E.
Published: February 2015

A previously developed general theory for the nonlinear evolution of external ideal MHD modes is applied to the special case of the m = n = 1 kink-mode in z-pinch equilibria with constant profile of the safety factor q. The Kruskal-Shafranov stability boundary q = - 1 eludes application of this theory since the kink-mode degenerates there. At the second stability boundary of the mode, stabilization as well as destabilization become possible depending on which values of the aspect ratio and the distance of a stabilizing wall are given.
On the Integrability of an Attracting System of Nonlinear Oscillators
Authors: Tasso H.
Published: February 2015

The problem of the integrability of a peculiar system of nonlinear oscillators is considered. While the case of two oscillators is integrable, the case of many is open. The Lax pair method is not applicable to such a system.
Volume Ignition in Pellet Fusion to Overcome the Difficulties of Central Ignition
Authors: Hora Heinrich
Published: February 2015

Since C. Yamanaka et al. demonstrated that the best fusion gains from laser irradiated pellets result only when central shocks are avoided and an ideal volume compression is achieved, the problems o f the central (spark) ignition with necessary densities of 1000 times the solid state may be overcome. Based on an analytical formula of volume ignition, the new conditions should provide reactor adequate laser fusion with compression to 50 to 100 times solid state.
The Microwave Spectrum of 4-Methylthiazole: Methyl Internal Rotation, 14N Nuclear Quadrupole Coupling and Electric Dipole Moment
Authors: Jäger W. , Mäder H.
Published: February 2015

The microwave spectrum of 4-methylthiazole has been investigated in the frequency region from 8 to 36 GHz, employing both Fourier transform and Stark spectroscopy. The results of 14N quadrupole hyperfine structure, methyl internal rotation and fourth order centrifugal distortion analyses are given. The dipole moment components could be determined from the Stark splittings of some rotational lines.
Chromospheric and Coronal Heating Due to the Radiation and Collisional Damping of Fast Magnetosonic Surface Waves
Authors: Sahyouni W. , Kiss’ovski Zh. , Zhelyazkov I.
Published: February 2015

We study the propagation of surface/pseudosurface modes in the structured solar atmosphere assuming that the surface waves m ay be able to heat the chromosphere and corona. The wave energy can be dissipated by radiation, ion viscosity, and electron heat conduction . For the solar corona, it is found that the pseudosurface waves, trapped in the coronal loops, dissipate efficiently only if their periods are longer than 200 seconds and only if the background magnetic field is smaller than 5 gauss.