bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep Inelastic Neutron Scattering in the Study of Atomic Momentum Distributions
Authors: Evans Alan C. , Mayers Jerry , Timms David N. , Cooper Malcolm J. 
Published: February 2015

Abstract
The electron-volt spectrometer (EVS) at the pulsed neutron source facility (ISIS) is being developed for the study of atomic momentum distributions. Neutrons with energies in the range 1 to 100 eV are incident on the sample, and the time-of-flight (TOF) spectrum of the scattered beam is measured by an array of fixed detectors. A resonant foil difference technique is used to yield a set of TOF spectra for those neutrons scattered into a fixed energy and through fixed angles. Information on the momentum distribution of the target nuclei can be deduced within an impulse approximation in a procedure analogous to that in Compton scattering of electrons by photons.
Crystalline compounds containing aligned hydrogen bonds and other hydrogenous compounds are of particular interest owing to the high cross-section of the proton at these neutron energies. With improved statistical accuracy of the data it is anticipated that deviations of the proton's potential from a harmonic potential may be determined. Non-hydrogenous systems have also been investigated. A description is given of the basic theory and interpretive method. Data obtained on numerous systems are presented and discussed.
On Spanning Trees in Catacondensed Molecules
Authors: Gutman I. , Mallion R. B. 
Published: February 2015

Abstract
Among all catacondensed benzenoid molecules the unbranched systems possess the largest number of spanning trees. Some other relations for the spanning-tree count of catacondensed benzenoids are also reported. The results obtained continue to hold for catacondensed molecules composed of rings the size of which differ from six. The propositions reported do, however, depend for their validity on there being rings of only one size in the catacondensed system under study.
Thermodynamics of the HSO4
– Formation in Aqueous Solutions up to 473 K and 975 bar
Authors: Bilal B. A. , Müller E. 
Published: February 2015

Abstract
The equilibrium constant, partial molal volume, entropy and enthalpy of the formation of HSO4
- ion in aqueous solutions have been determined up to 473 K and 975 bar at the ionic strengths 1 = 0 as well as in NaCl solutions having I = 1, 0.5 and 0.1 mol kg-1 At 473 K, for instance, the thermodynamic formation constant K0 decreases by ≈ 0.75 log units from saturation pressure to 975 bar. The corresponding decrease of the apparent formation constant Q at I = 1 m is ≈ 0.6 log units. The increased dissociation at higher pressure leads to a decrease of the partial molal volume and entropy due to the resulting higher electrostriction in the system.
Inner Bremsstrahlung Accompanying the Non-Unique First Forbidden β-Decay of 141Ce
Authors: Khalil E. I. 
Published: February 2015

Abstract
The inner Bremsstrahlung (I.B.) spectrum accompanying the β-decay of 141Ce (non-unique first forbidden β-transition) was measured using a single channel scintillation spectrometer. The measured I.B. was analyzed by the variable width peeling-off method. This analyzed and corrected I.B. was compared with those calculated according to the original theories of Knipp and Uhlenbeck as well as of Bloch (KUB), the coulomb corrected theories of Lewis and Ford and of Nilsson, and according to detour-transition calculations of the Ford and Martin theory. Ths shape correction factor suggested by Konopinski and Uhlenbeck on the Fermi β-decay theory was applied to the calculated I.B. based on Nilsson's theory (modified KUB theory). The experimental results are in better agreement with the modified KUB theory than the other theories.
Is the Gravitational Force Elementary?
Authors: Stumpf H. , Borne Th. , Kaus H. J. 
Published: February 2015

Abstract
The gravitational force is assumed to be mediated by spin 2 gravitons which are composed of four spin 1/2 (sub-) fermions. The dynamics is governed by a nonlinear spinorfield equation with nonperturbative Pauli-Villars regularization and canonical quantization. On the quantum level the fermion dynamics is expressed by a functional equation for algebraic state functionals, and the "graviton" (functional) states are defined to be solutions of the diagonal part of this equation. The effective interaction between such graviton states and fermions is studied by means of a weak mapping between the original functional equation and an effective functional equation for gravitons and fermions. In the low energy limit this mapping produces for the effective fermion dynamics (apart from selfinteractions) a Dirac equation in anholonomic coordinates coupled to the anholonomic connections of a gravitational field, i.e. the usual phenomenological expression for a gravitational force acting on spin 1 /2 fermions.
Monomer and Excimer Fluorescence of 2-Phenylindole in p-Xylene at 20 °C Studied by Frequency-Domain Fluorometry
Authors: Kawski A. , Gryczyński I. , Maliwal B. P. , Piszczek G. 
Published: February 2015

Abstract
The effect of 2-phenylindole (2PI) concentration in p-xylene upon the fluorescence decay time was investigated by frequency-domain fluorometry. The fluorescence decay of a dilute (10~ 5 M) 2PI solution in p-xylene at 20 °C is single exponential with the mean decay time t = 1.87 ns and practically independent of the observation wavelength (A obs) in the fluorescence band. The fluores-cence decay in a highly concentrated solution (6 x 10" 3 M) is heterogenic and depends on A obs . For a given modulation frequency (~ 200 Hz), the fluorescence phase shifts at the longwave observation (440-480 nm) distinctly exceed 90°, thus clearly indicating that the observed (excimer) fluorescence results from a process taking place in the excited state. The fluorescence decays were measured at seven values of A obs (360-480 nm), and all the results were analyzed comprehensively (tj and t 2 are equal for all A obs ; the amplitudes are different). The lifetimes of the excimer state is relatively short (~3.5 ns). Radiative (r e) and non-radiative (t,) rate constants for monomer fluorescence of 2PI in p-xylene were determined using appropriate data from photo-and radioluminescence measure-ments.
Comment on "Surrealistic Bohm Trajectories"
Authors: Dürr Detlef , Fusseder  , Goldstein Sheldon , Zanghi Nino 
Published: February 2015

Abstract
From the perspective of orthodox quantum theory, no meaning can be assigned to the notion of the "slit" through which the atom passed in the experiments under discussion in this paper. From a Bohmian perspective this notion does have meaning. Moreover, when we compare the answer provided by BM with the answer provided, not by orthodox quantum theory, but by a naive, largely incoherent operationalism, we obtain different answers. So what?
Stochastic Resonance in Experiment
Authors: Kittel A. , Richter R. , Hirsch M. , Flätgen G. , Peinke J. , Parisi J. 
Published: February 2015

Abstract
We observe the phenomenon of stochastic resonance in a semiconductor experiment. Originally, such an effect was predicted for bistable dynamical systems that are influenced by a periodic modulation as well as a random perturbation. In that case, a "resonance" peak can be observed in the power spectrum. The phenomenon investigated is the low-temperature impact ionization breakdown. There, bistability results from the competing states of low and high conductance.
On the Scaling Function of Lyapunov Exponents for Intermittent Maps
Authors: Stoop R. , Parisi J. 
Published: February 2015

Abstract
The scaling function of Lyapunov exponents for intermittent systems is full of particularities if compared with hyperbolic cases or the usual, nonhyperbolic, parabola. One particularity arises when this function is calculated from finite-time Lyapunov exponents: Different scaling properties with respect to the length of the finite-time chains emerge. As expected from random walk models, the scaling of an ensemble with non-Gaussian fluctuations evolves for certain values of the external parameter.
A "Superfat" Attractor with a Singular-Continuous 2-D Weierstrass Function in a Cross Section
Authors: Rössler O. E. , Hudson J. L. 
Published: February 2015

Abstract
A 3-D invertible map generating a 4-loop solenoid attractor is presented. The attractor of the "standard" 4-solenoid turns out to be "fat" - that is, fractal dimensionality exceeds topological dimensionality by more than unity. If a fourth variable that is weakly damped is added to this 3-variable map, a new type of attractor is generated. In a cross section it is a continuous nowhere-differentiable function over a 2-D domain which is a 2-D Cantor set. Such an object can be called a "singular-continuous 2-D Weierstrass function". The latter can be "superfat" (dimension gap larger than 2). Realistic systems possessing attractors of this new type are possible.
Differential Thermal Analysis under Pressure on Cyanocyclohexane, 1,2,3,4-Tetrahydro-5,6-dimethyl-1,4-methanonaphthalene, and 2-Methyl-2-propanol
Authors: Reuter J. , Brückert T. , Würflinger A. 
Published: February 2015

Abstract
Differential thermal analysis has been performed on cyanocyclohexane (CCH), 1,2,3,4-tetrahydro-5,6-dimethyl-1,4-methanonaphthalene (TDMN), and 2-methyl-2-propanol (t-butanol) up to 300 MPa. The latter compound was also investigated dielectrically. CCH displays an ODIC phase that transforms only reluctantly to the low-temperature stable phase II. Annealing under pressure can appreciably accelerate this transformation. For all three compounds the phase diagrams were established. For CCH and TDMN also the pressure dependence of the glass transition has been determined.
A Broadband Microwave Fourier Transform Spectrometer, Especially Designed for Stark Effect Investigations of Almost Nonpolar Molecules; the Electric Dipole Moment and the Anisotropy in the Static Electric Polarizability Tensor of 1,1-Dideuteroallene, D2C = C = CH2
Authors: Meyer V. , Sutter D. H. 
Published: February 2015

Abstract
A bridge type microwave Fourier transform spectrometer, equipped with flat oversized Stark cells and an operational range from 8 GHz to 40 GHz is described. As application we report the experimental determination of the vibronic ground state dipole moment and of the anisotropy in the static polarizability of 1,1-dideuteroallene. Our experimental values are: μa = 0.0053(2) D for the dipole moment, and (α∥ - α⊥) = 4.26(6) • 10-24 cm3 , for the polarizability anisotropy.
Crystal Structure of Trimethylammonium Perchlorate in Three Solid Phases Including the Ionic Plastic Phase Obtainable above 480 K
Authors: Ishida Hiroyuki , Kubozono Yoshihiro , Kashino Setsuo , Ikeda Ryuichi 
Published: February 2015

Abstract
The crystal structures of (CH3)3NHClO4 in three solid phases were studied by X-ray diffraction techniques. X-ray powder patterns taken at ca. 500 and 445 K revealed that the plastic phase (Phase I) attainable above 480 K crystallizes in a CsCl-type cubic structure with a = 5.845 (1) Å, Z = 1, V = 199.7 (2) Å3, and Dx = 1.327 g cm -3, while Phase II, stable between 480 and 396 K, forms a tetragonal structure with a = 9.912 (4), c = 7.01 (2) Å, Z = 4, V = 689 (3) Å3, and Dx = 1.54 gem -3. The room temperature phase (Phase III) was studied by single crystal X-ray diffraction and found to form a monoclinic lattice with space group P21 , a = 5.749(1), b = 8.670(1), c = 7.5585 (9) Å, ß = 102.66 (1)°, Z = 2, V = 367.6 (2) Å3 , and Dx= 1.441 g cm -3. Thermal measurements, differential thermal analysis and differential scanning calorimetry, were carried out on these solid phases, and the obtained results were compared with those observed for (CH3)3NHBF4.
Search for an Admixture of a 17 keV Neutrino in the β Decay of 35S
Authors: Müller S. , Shiping Chen , Daniel H. , Dragoun O. , Dragounová N. , Hagn H. , Hechtl E. , Hiddemann K.-H. , Špalek A. 
Published: February 2015

Abstract
The β spectrum of a mass-separated thin 35S source has been measured with a small-volume Si photodiode. The energy-dependent response function of the total experimental set-up was calculated by the Monte Carlo method without any adjustable parameter. For an admixture of the hypothetical 17 keV neutrino, an upper limit of 0.59% (95% CL) was determined. Neglecting electron scattering on the spectrometer diaphragm was shown to generate a false 17 keV neutrino admixture of 0.3%.
Low Frequency Nuclear Quadrupole Resonance with SQUID Amplifiers
Authors: Clarke John 
Published: February 2015

Abstract
The dc SQUID (Superconducting QUantum Interference Device) can be configured as an ampli­fier of spin-echos with a noise temperature of approximately 10 mK (f/1 M Hz) at an operating temperature of 1.5 K. A Fourier transform spectrometer based on a SQUID with a superconducting input circuit and operated in a flux-locked loop is used to obtain nuclear quadrupole resonance (NQR) spectra in a broadband m ode over the bandwith 0 -1 M Hz. Spin-echo spectra of 14N in NH4ClO4 reveal sharp NQR resonances, obtained simultaneously, at 17.4, 38.8 and 56.2 kHz. At 1.5 K, the measured longitudinal and transverse relaxation times T1 and T2 for the 38.8 kHz transition are 63 ± 3 ms and 22±2 ms, respectively.
Nitrogen-14 NQR Multiple-Pulse Spin-locking in the Axial Electric Field Gradient
Authors: Furman G . B. 
Published: February 2015

Abstract
The behavior of a nuclear spin-1 system with the Hamiltonian including: a) the interaction of the electric quadrupole moment of nuclei with the axial gradient of the crystal electric field; b) a homonuclear and heteronuclear dipole-dipole coupling; and c) the interaction with a multiple pulse radiofrequency field of arbitrary orientation was considered. The effective Hamiltonian is con­structed by using the Floquet theory. The secular parts of the homonuclear and heteronuclear dipole-dipole interaction was found and the quasi-equilibrium magnetization was calculated.
Theoretical Investigation on the Nuclear Quadrupole Interaction of CH3Cl, CH2Cl2 and CHCl3
Authors: Frantz Gerald , Dufner Hagen , Schmidt P.C. 
Published: February 2015

Abstract
The nuclear quadrupole interaction of 35Cl in CH3Cl, CH2Cl2 and CHCl3 has been studied theoretically by the Hartree-Fock-Roothaan procedure. The influence of the crystal field on the nuclear quadrupole coupling constant is incorporated by the cluster approach and by using point charges that are consistent with the external potential.
Quadrupole Coupling Assignments in Inorganic Periodic Systems by ab initio Calculation of Electric Field Gradients
Authors: Palmer Michael H. , Blair-Fish John A. 
Published: February 2015

Abstract
Ab initio SCF calculations were performed in the unit cell environment, making use of the periodic behaviour to compute a wave-function for the bulk material. Electric field gradient (EFG) calcula­tions were performed on the resulting wave-functions, and these are compared with experimental quadrupole coupling parameters. Examples of inorganic molecular and ionic crystals (nitrogen, chlorine and lithium nitride) and minerals or partially covalent lattice structures (alumina, petalite, α-quartz, boron oxide, boron nitride and sulphur nitride) are described. The effects of the basis set in these calculations are considered, and the limitations imposed by the nature of the calculation are described.
A 35Cl NQR and MNDO study of 3,5-dichloro-1,2,4-triazole and its ionic forms
Authors: Dolgushin G.V. , Lazarev I.M . , Larina L.I. , Lopyrev V.A. , Voronkov M .G . 
Published: February 2015

Abstract
The 35Cl NQR spectra of 3,5-dichloro-1,2,4-triazole derivatives have been examined. MNDO calculations of chloroazoles (imidazole, triazole) including their ionic forms have been carried out. In 3,5-dichloro-l,2,4-triazole complexation and protonation occur of position 4 at the triazole ring.
35Cl NQR of 1,5,2-Diazaphosphorine Derivatives
Authors: Dolgushin G. V. , Nikitin P. A. , Sapozhnikov Yu. E. , Dmitrichenko M. Yu. , Rozinov V. G. , Voronkov M. G. 
Published: February 2015

Abstract
NQR frequencies and asymmetry parameters (η) of 35Cl chlorine-containing 1,5,2-diazaphosphorine derivatives are reported and discussed. NMDO calculations with total optimization of geometry have been carried out. The νcal and ηcal values, calculated by means of the Townes and Dailey theory, correlate well with the experimenal data.
Bromine NQR and Crystal Structures of Tetraanilinium Decabromotricadmate and 4-Methylpyridinium Tribromocadmate
Authors: Ishihara Hideta , Krishnan V. G. , Dou Shi-qi , Paulus Helmut , Weiss Alarich 
Published: February 2015

Abstract
The 79,81Br NQR spectra of tetraanilinium decabromotricadmate (1) and 4-methylpyridinium tribromocadmate (2 ) were studied as function of temperature and their crystal structures were determined. (C6H5NH3)4Cd3Br10 (1): Space group D1 5
2h - Pbca , Z = 4, a = 2507.8(7) pm, b = 1985.4(5)pm, c = 763.0(2)pm. Characteristic for the structure are trioctahedral units [Cd3Br10] condensed to planes. Within the units the octahedra are face connected and further condensed to planes via common corners. Two types of hydrogen bonds are observed. The 81Br NQR lines with frequencies (MHz, 298 K) of 62.98, 52.59, 43.39, 41.82, and 40.71 are little temperature dependent with positive and negative coefficients. The wide frequency range of the NQR lines is reflected by the wide range of the intraionic distances, 263 ≤ d(Br-Cd)/pm ≤300.
(4-(CH3)C5H4NH)CdBr3 (2): C5
2h - P21/n, Z = 4, a = 1228.8(5}pm, b= 1168.5(5)pm, c = 758.3(3)pm, β = 95.30(1)°; the CdBr⊖
3 ions are condensed to chains. The 81Br NQR spectrum is a triplet with frequencies (MHz, 298 K) of 66.01, 55.39, and 50.75. The temperature dependence is small, with positive and negative temperature coefficients. The distances d(Cd-Br) are 256 pm (Cd-Br(2)), 261 pm (Cd -Br(1)), and 284 pm (Cd-Br(3)) and in the chain [CdBr3]Br(1) and Br(3) are bridging atoms.
The relations between Br-NQR and crystal structures are discussed.
Effect of Deuteration on the Phase Transitions and on the Critical Dynamics in Ammonium Hexachlorometallates
Authors: Pelzl J. , Dimitropoulos C. 
Published: February 2015

Abstract
Recent and novel data obtained from chlorine NQR measurements on natural and deuterated (NH4)2MCl6 compounds are discussed with special regard to the influence of the ammonium-ion dynamics on the structural stability of these crystals. The temperature dependence (4.2 K to 350 K) of the chlorine NOR frequency vQ and relaxation rates T1
-1 , T2
-1 obtained from the natural ammonium salts of Sn, Pd, Os, Pb, Te, Se and from the deuterated salts of Sn, Te and Se are analysed. Slight deviations from the normal temperature behaviour of vQ and T1
-1 are found in Sn, Pd and Os compounds which stay cubic in the whole temperature range. The ammonium compounds of Pb and Te undergo a structural transformation between 80 K and 90 K from the cubic to a trigonal phase which is distinguished by the preservation of the single line spectrum of the chlorine NQR below rel. The observed divergence of T1
-1 at the transition point can be described in terms of a spin-phonon process in the presence of an overdamped soft mode. Deuteration of (NH4)2TeCl6 only slightly affects the transition of Tc2 but leads to new structural changes at lower temperatures. Whereas the natural compound stays trigonal down to 4.2 K the deuterated crystal undergoes two additional structural transformations at Tc2 = 48 K and Tc3 = 28 K which are correlated with a slowing down of the deuteron motion. Approaching Tc2 from above, the spin-lattice relaxation rate and the spin-spin relaxation rate of the chlorine NQR exhibit distinct anomalies which are attributed to limited jumps of the octahedron in a shallow potential. The barrier height of this potential deduced from the chlorine NQR spin-lattice relaxation rate is 400 K. The transition at Tc2 is explained by the condensation in one minimum of this potential. At Tc3 a long range correlation is formed which is accompanied by a rotation of the octahedron about its fourfold axis. A similar mechanism is adopted for the transitions observed in (NH4)2SeCl6 at Tc= 24 K and in (ND4)2 SeCl6 at Tc = 48 K.
Study of the Molecular Dynamics from Deuterium Zeeman and Quadrupolar NMR Relaxation of 4,4´-di-n-Heptylazoxybenzene in the Nematic and Smectic A Phases
Authors: Forte C. , Geppi M. , Veracini C. A. 
Published: February 2015

Abstract
The deuterium spin-lattice (T1Z) and quadrupolar (R1Q) relaxation times of the liquid crystal 4,4´-Heptyl-azoxybenzene (HAB), deuterated on the aromatic rings and the first methylene group of the chains, have been measured by means of the Jeener-Broekaert pulse sequence at two different frequencies (10 and 46.04 M Hz) and throughout the nematic and the smectic A phase. By applying suitable models, we have determined rotational and reorientational diffusion coefficients and evalu­ated the contribution of the different motions (internal, molecular and collective) to the relaxation. In particular we have found a non negligible contribution from order director fluctuations.
A comparison between the T1Z and T1Q measurements performed by means of Jeener-Broekaert and Wimperis pulse sequences is also shown.
X-Ray Diffraction Study of Methanol-Water Mixtures
Authors: Bakó I. , Pálinkás G. , Heinzinger K. 
Published: February 2015

Abstract
X-ray diffraction patterns o f m ethanol-water mixtures with mole fractions of methanol molecules o f 0.1, 0.25 and 0.9 have been measured. The experimental structure functions of mixtures are compared with those of pure solvents and with recent Molecular Dynamics results. Difference structure functions similar to thermodynamic excess functions are introduced for the analysis of methanol-water interactions. The comparison of the total and the difference structure functions from experiments and simulations shows an overall good agreement.
Scalar Potentials and the Dirac Equation
Authors: Bergerhoff Bastian , Soff Gerhard 
Published: February 2015

Abstract
The Dirac equation is solved for various types of scalar potentials. Energy eigenvalues and normalized bound-state wave functions are calculated analytically for a scalar 1 / r-potential as well as for a mixed scalar and Coulomb 1 / r-potential. Also continuum wave functions for positive and negative energies are derived. Similarly, we investigate the solutions of the Dirac equation for a scalar square-well potential. Relativistic wave functions for scalar Yukawa and exponential potentials are determined numerically. Finally, we also discuss solutions of the Dirac equation for scalar linear and quadratic potentials which are frequently used to simulate quark confinement.
The Structure of Amorphous Platinum Disulfide as Studied by Anomalous X-ray Scattering
Authors: Saito Masatoshi , Wakeshima Makoto , Sato Nobuaki , Fujino Takeo , Waseda Yoshio , Matsubara Eiichiro , Jacob K. Thomas 
Published: February 2015

Abstract
Anomalous X-ray scattering (AXS) has been applied to study the structure of amorphous plati­ num disulfide, Pt1-xS2, prepared by the precipitation process. The local atomic arrangement in amorphous Pt1-xS2 was determined by the least-squares variational method so as to reproduce the experimental differential interference function at the Pt Lm absorption edge by the AXS method as well as the ordinary interference function by Mo K α. The structural unit in amorphous Pt1-xS2 is found to be a PtS6 octahedron, similar to that in crystalline PtS2. These octahedra share both their corners and edges, while only edge-sharing linkages occur in crystalline PtS2