bluuebunny/crossref_metadata_2025 huggingface dataset:
Doppler Line Broadening from the Asymptotic Cauchy Distribution
Authors: Lavenda B. H.
Published: February 2015

The half-width of Doppler broadening is derived without assuming Maxwell's distribution for the velocities of the radiating atoms. In the absence of Doppler broadening there is only natural radiation broadening, and by thermalizing the asymptotic Cauchy distribution one obtains asymp-totic double exponential distributions for the largest (blue) and smallest (red) values of the frequency shift. These are the relevant extreme value distributions for largest and smallest values. Since the mean values are opposite and equal there is a zero shift in the line, while the standard deviation gives an expression for the half-width to within 2% of the Doppler half-width obtained from the Maxwellian when the damping coefficient is taken as the ratio of the natural radiation damping coefficient to the fine structure constant.
Deterministic Chaos in the Dynamics of a Freely Jointed Chain with Three Degrees of Freedom
Authors: Siegert Georg R. , Winkler Roland G. , Reineker Peter
Published: February 2015

The dynamics of a short freely jointed chain of three segments is investigated numerically. The chain consists of mass points connected by massless rigid rods, its initial and final points being fixed. Thus the chain represents a holonomically constrained system with three degrees of freedom. It is shown that the motion of the mass points can be chaotic; the occurrence of chaos depends on the initial conditions of the motion, the end-to-end distance of the chain, and the angular momentum about the axis of the stretching direction. Moreover, the chain more likely exhibits regular than chaotic behavior. The numerical results are presented in the form of Poincare surfaces of section, including the use of a slice technique, as well as in the form of power spectra.
High-Resolution Vibrational Spectra of Furazan III. The A1 Fundamentals v3 at ~ 1316 cm-1 and v4 at ~ 1036 cm-1 from Fourier-Transform Infrared Spectroscopy
Authors: Stiefvater Otto L.
Published: February 2015

With prior information on vibrationally excited states from DRM microwave spectroscopy, two B-type high-resolution FT-IR bands of furazan were examined to yield the band origins v0
3 = 1316.2254 cm-1 and v0
4 = 1036.1689 cm-1 with an estimated absolute uncertainty of ±0.0001 cm-1 . The rotational and distortion constants of both fundamental states were refined by the combination of rotational with rovibrational data in the least-squares fits of the bands.
NMR and Dilatometric Studies on [N(CH3 )4]3 M2X9 (M = Sb, Bi; X = Cl, Br)
Authors: Medycki W. , Jakubas R. , Piślewski N. , Lefebvre J.
Published: February 2015

Thermal expansion studies on [N(CH3)4]3Sb2Cl9 and [N(CH3)4]3Sb2Br9 are reported. The relaxation times 1H T1 were measured for [N(CH3)4]3 Bl2Cl9 , [N(CH3)4]3Sb2 Br9 , and [N(CH3)4]3 Bi2 Br9 in the temperature range 100-290 K. To interpret the T1 data on [N(CH3)4]3Bi2Cl9 the method of T1 calculation reported by Takeda et al. has been applied successfully. Two different, inequivalent types of [N(CH3)4]3
+ cations for all tetramethylammonium crystals are found.
Highly Resolved MR Imaging of Arbitrary Subregions in Large Objects by a Whole-Body Imager
Authors: Pfeffer Karin , Pfeffer Markus , Jung Wulf-Ingo , Lutz Otto , Schick Fritz
Published: February 2015

Highly resolved images of defined regions of interest within extended objects were obtaind with a 1.5 T whole-bode imager and standard hardware. The high-resolution spin echo imaging sequence avoids aliasing and allows pixel resolutions down to 39 µm which are confirmed by phantom measurements. The application of the sequence to large biological objects such as, for example, an amaryllis bulb results in images which provide much detail which could not be resolved with standard sequences.
Composite Particle Theory in Quantum Electrodynamics
Authors: Stumpf H. , Fauser B. , Pfister W.
Published: February 2015

Without use of pathintegral formalism a composite particle effective dynamics is developed for spinor quantum electrodynamics. By algebraic evaluation of spinor quantum electrodynamics in Coulomb gauge a corresponding functional equation is derived. The commutation rules for the transversal electromagnetic field can be deduced as a consequence of this formalism. By application of weak mapping theorems the QED functional equation can be mapped onto a functional equation for composite particles with mutual interaction and interaction with the electromagnetic field. The formalism is demonstrated for positronium states. The incorporation of renormalization into this scheme is verified.
14N Nuclear Quadrupole Coupling Constants of Acetamide and α-Fluoroacetamide
Authors: Heineking N. , Dreizler H.
Published: February 2015

The 14N nuclear quadrupole hyperfine structures in the rotational spectra of acetamide, CH3CONH2 , and α-fluoroacetamide, FCH2CONH2 , have been resolved. From the observed patterns, the quadrupole coupling constants have been determined with high precision. The results provide evidence of considerable derealization of the nitrogen lone electron pair. For acetamide, the full coupling tensor has been determined from a combined analysis of the ground and first excited state of the methyl group internal rotation.

The spectrum of α-fluoroacetamide-[15N] has been obtained for the first time, and a refined structure is proposed.
An Investigation of the Structure of Aqueous Electrolyte Solutions by Statistical Geometry
Authors: Kiselev M. , Poxleitner M. , Seitz-Beywl J. , Heinzinger K.
Published: February 2015

Statistical geometry is employed for a quantitative description of deviations from regular octahedrality of water around monovalent ions and from regular tetrahedrality of solvent water around water molecules. For these deviations a new criterion is presented by taking into account octahedral and tetrahedral spatial symmetry groups. A geometrical definition of structure making and structure breaking is proposed and illustrated on the basis of molecular dynamics simulations of 2.2 molal aqueous KCl and LiI solutions with the flexible BJH model of water.
Electron Distribution in Some Zincblende-Type Crystals
Authors: Uno Ryosei , Ozawa Haruo , Ishigaki Jun , Yukino Ken
Published: February 2015

The elctron density distribution in crystalline ZnSe and ZnTe has been measured by X-ray diffraction on powder samples and is compared with the results for other zincblende-type crystals. It is shown that the data for these two compounds corroborate the linear dependence on the bond charge that has been found earlier for the effective atomic charge from infrared reflection measurements, the optical dielectric constant and the ionicity estimated from pseudopotential band theory.
Charge Density Study on Bullvalene (C10H10 )
Authors: Koritsánszky T. , Buschmann J. , Luger P.
Published: February 2015

Low-temperature single-crystal neutron and X-ray diffraction data were collected for bullvalene (Figure 1). X -N Fourier and multipole static deformation electron density maps were calculated and compared. Atomic mean-square-displacement parameters were analysed in the framework of the rigid-body motion model and the residual amplitudes (UOBS - UTLS) were graphically interpreted. The preliminary results presented here reveal either a bias in the X-ray anisotropic displacement parameters (ADPs) due to improper modelling of the electron density or unresolved errors in the neutron data.
Electrostatic Properties of Molecules from the X-Ray Charge Density. Application to Deuterated Benzene, 1-Alanine and d,l-Histidine
Authors: Su Zhengwei , Coppens Philip
Published: February 2015

It has been shown (Z. Su and P. Coppens, Acta Cryst. A 48, 188 (1992)) that the electrostatic potential, the electric field, and the electric field gradient (EFG) can be expressed in closed forms in terms of the positions and the charge-density parameters of individual atoms, whose aspherical density is described by a pseudoatom model (e.g., N. Hansen and P. Coppens, Acta Cryst. A 34, 909

(1978)). A F o r t r a n program Molprop91 based on this method has been written (Z. Su, State Univ. of New York at Buffalo 1991). The method has been applied to the title compounds. Low-temperature X-ray diffraction data of fully deuterated benzene (G. A. Jeffrey, J. R. Ruble, Y. Yeon, and C. Lemann, private communication, 1991), /-alanine (R. Destro, R. E. Marsh, and R. Bianchi, J. Phys. Chem. 92, 966 (1988) and d,/-histidine (N. Li, Ph.D. thesis, State University of New York at Buffalo 1989) were analyzed using the least-squares deformation density refinement program Lsmol90 (a

modified version of M o l l y ) . Molprop91 was subsequently used to calculate the electrostatic-potential maps in selected sections, and at the nuclear positions. For the latter, the EFGs were also evaluated. The electrostatic potentials were used to fit net atomic charges and estimate the molecular energies. Errors in the derived quantities are given.
Spin Transfer through Hydrogen Bonding in [CO(NH3)5(OH2)][Cr(CN)6] ?
Authors: Figgis B. N. , Kucharski E. S. , Vrtis M.
Published: February 2015

A polarised-neutron diffraction experiment on [Co(NH3)5(H2O)][Cr(CN)6] shows the unexpected features of spin populations on the cobalt ((0.5(2) e) and the "ammine" hydrogen (0.8(1) e in total) atoms. A local density approximation DV-Xα calculation on a unit that models the molecular geometry in the crystal returns features that are broadly in agreement with the experiment. The calculation also reproduces the major features of a charge density experiment on the complex, including the low (±1.6 e) charges on the ions, in place of the formal ±3 e.
Nonnuclear Maxima in the Charge Density
Authors: Edgecombe Kenneth E. , Smith, Jr. Vedene H. , Müller-Plathe Florian
Published: February 2015

Basis-set and electron-correlation effects on the appearance and disappearance of nonnuclear maxima in the electron density are examined in Li2 , Na2 , Na4 and Na5 . It is shown that nonnuclear attractors can be removed in all cases except Li2 . The appearance of a pseudoatom in a lithium molecule correlates remarkably well with the size of the region, in an atomic calculation, of V2r(r) for the valence shell of the atom. This and the fact that the pseudoatom is also present in the promolecule indicate that the pseudoatoms are remnants of, or in fact are portions of, atoms that are not perturbed enough in the molecule to remove an essentially atomic characteristic.
Electron Charge and Current Densities, the Geometrie Phase and Cellular Automata
Authors: Sukumar N. , Deb B. M. , Singh Harjinder
Published: February 2015

Some consequences of the quantum fluid dynamics formulation are discussed for excited states of atoms and molecules and for time-dependent processes. It is shown that the conservation of electronic current density j(r) allows us to manufacture a gauge potential for each excited state of an atom, molecule or atom in a molecule. This potential gives rise to a tube of magnetic flux carried around by the many-electron system. In time-dependent situations, the evolution of the electronic density distribution can be followed with simple, site-dependent cellular automaton (CA) rules. The CA consists of a lattice of sites, each with a finite set of possible values, here representing finite localized elements of electronic charge and current density (since the charge density r

no longer suffices to fully characterize a time-dependent system, it needs to be supplemented with information about the current density j).Our numerical results are presented elsewhere and further development

is in progress.
A Comparison between Polyatecylene and Polycarbonitrile
Authors: Springborg Michael
Published: February 2015

Results of a theoretical, comparative study of the electronic properties of trans-polyacetylene and polycarbonitrile are reported. Polyacetylene consists of zigzag chains of CH units, whereas polycarbonitrile has every second CH unit replaced by an N atom. Ground-state properties (structure, electronic bonds and bands, densities of states, momentum distributions, and reciprocal form factors) of the periodic, infinite, isolated chains are studied by means of first-principles, density-functional calculations. It is demonstrated how the presence of the (nitrogen) heteroatoms in the backbone of polycarbonitrile leads to a partial localization of the electrons. In order to investigate charged chains, model calculations are subsequently performed. These indicate solitons but not polarons to be stable. In total, the analysis demonstrates how the combination of information that can be obtained from various experiments provides a detailed description of the compounds.
On the Inference of the One-Particle Density Matrix from Position and Momentum-Space Form Factors
Authors: Schmider Hartmut , Smith, Jr. Vedene H. , Weyrich Wolf
Published: February 2015

A modification of a recently developed method for the least-squares reconstruction of a one-particle reduced density matrix from experimentally accessible expectation values is applied to the test systems of atomic beryllium and neon. The improvement of the resulting matrices through inclusion of electron correlation is demonstrated. Their quality is judged by comparison of the moments of the position and momentum densities and of the spherically averaged density matrix in a suitable representation.
Nondiagonal Response of Electrons by Coherent Inelastic X-Ray Scattering
Authors: Kaprolat A. , Schülke W.
Published: February 2015

The experimental knowledge of the dielectric response of electrons within a solid is up to now mainly gained by inelastic scattering experiments, using a plane wave as initial state of the probe particle. These experiments allow the measurement of the dynamical structure factor, related to diagonal elements of the inverse dielectric matrix ε-1. We present a new type of scattering experiment that uses as initial state of the probe a standing wave field, thus allowing the experimental determination of non-diagonal elements of ε-1. Comparison of the experimental results with a plasmon-band model leads to direct experimental evidence for plasmon-banding in Si.
The Effect of Correlation on the Double Ionization of Helium by Fast Electrons
Authors: Joulakian B. , Cappello C. Dal
Published: February 2015

The double ionization of helium by fast electrons is studied by using a correlated double continuum wave function describing the two ejected electrons.
Recent Advances in Compton Scattering
Authors: Dobrzyński L.
Published: February 2015

A review of achievements in the field of Compton spectrometry in the years that elapsed from the last Sagamore meeting (1988) is presented. Some physical problems that have either appeared as new or became clarified are described. Special emphasis is put to the results obtained by means of magnetic Compton scattering.
Performance of the Compton Spectrometer at HARWI/HASYLAB
Authors: Schmitz J. R. , Schulte-Schrepping H. , Berthold A. , Mourikis S. , Schülke W.
Published: February 2015

Performance, resolution and spectral throughput both of the sagittally focusing monochromator and of the alternately installed two analysing systems, a Cauchois-type cylindrically bent crystal analyser for Compton-profile measurements, and a spherically bent crystal analyser for S(q, ω)-measurements, of the new Compton spectrometer at the HARWI (harter Röntgen Wiggler) of the DORIS storage ring are presented together with two typical applications.
The Dynamic Structure Factor of LiC6 and KC8 : Inelastic Synchrotron X-Ray Scattering Results
Authors: Berthold A. , Gabriel K.-J. , Schülke W.
Published: February 2015

The dynamic structure factor S(q, ω) of electrons in lithium-intercalated graphite (LiC6) and potassium-intercalated graphite (KC8) for momentum transfer q || c-axis has been measured by inelastic synchrotron X-ray scattering. The dielectric function ε(q, ω) was deduced from the data and compared with ε(q, ω) of pristine graphite.

The main feature in the different Im [ε(q, ω)]-spectra, a more or less intense peak around 14 eV, can be assigned to maxima of the symmetry-projected joint density of occupied and unoccupied electron states near the Fermi level. Knowing the position of the occupied bands by photoemission experiments, predictions about the unoccupied π and interlayer states can be made.

In the case of LiC6 , a shift and broadening of the first Im [ε(q, ω)]-peak was found, which can be explained by a decrease of the energy of the interlayer-band because of the strong hybridization of this graphite-derived band with the Li metal 2s-band.

In the case of KC8 , a weakening of the first peak of Im [ε(q, ω)] was observed, which we attribute both to a decreasing overlap of the occupied s-derived state with the empty interlayer state and to a change of symmetry of the occupied π-derived states as well as of the empty rc-derived states.
Anisotropy of the Electron Momentum Distribution in Pyrolytic Graphite Studied Using a WKa1 Spectrometer
Authors: Manninen S. , Honkimäki V. , Suortti P.
Published: February 2015

A new spectrometer construction based on a high-voltage W-anode x-ray tube has been used to measure the directional Compton profiles of a pyrolytic graphite crystal. Owing to the focusing geometry, the monochromatic WKα1 t beam is very well collimated, which improves the momentum resolution compared with conventional241 Am spectrometers, operated almost at the same energy. The experimental anisotropy in the basal plane and in the direction of the c-axis is found to be very close to that of a recent calculation, based on the pseudopotential local-density-functional model.
The Asymmetry of the Compton Profiles and its Dependence on the Geometrical Resolution
Authors: Anastassopoulos D. L. , Priftis G. D.
Published: February 2015

The asymmetry of Compton Profiles (CPs) measured with a 60-keV 241 Am source on an Al monocrystal, cut along [111], is reported for three different geometrical resolutions. It is found that the geometry of the spectrometer has a substantial effect on the asymmetry of the CP. The better the geometrical resolution the smaller the asymmetry of the CPs.
Positron Annihilation Studies of the Electronic Structure and Fermiology of High-Tc Superconductors
Authors: Smedskjaer L. C. , Bansil A.
Published: February 2015

We discuss the application of the positron annihilation angular correlation (ACAR) spectroscopy for investigating the electronic structure and Fermiology of high-Tc superconductors, with focus on the YBa2Cu3O7 system where most of the experimental and theoretical work has to date been concentrated. Detailed comparisons between the measured 2D-ACAR positron spectra and the corresponding band theory predictions show a remarkable agreement (for the normal state), indicat-ing that the electronic structure and Fermi surface of this material is described reasonably by the conventional picture.
High-Resolution Neutron Spectroscopy for the Investigation of Hydrogen Diffusion and Molecular Rotations in Solids
Authors: Springer T.
Published: February 2015

An introductory survey on applications of high-resolution neutron spectroscopy is presented, dealing with the motion of hydrogen in solids, namely concerning (i) random rotational motions or stationary tunneling states of NH+
4-ions or CH3-groups, and (ii) diffusion of hydrogen in alloys. For the rotation of hydrogenous groups in solids, at higher temperatures rotational jumps can be found, whereas quantum states are observed by μeV-spectroscopy at temperatures below 50 K. On the other hand, hydrogen diffusion does not reveal pronounced evidence of quantum effects, except for hydrogen in a metal containing impurity atoms.
Deep Inelastic Neutron Scattering Studies of Atomic Momentum Distributions in Condensed Argon and Neon
Authors: Fradkin M. A. , Zeng S.-X. , Simmons R. O.
Published: February 2015

Using deep inelastic neutron scattering, direct measurements have been made, i) of the dynamic structure factor of a series of condensed argon samples over the temperature range 18 to 85 K, near melting (for wave-vector transfers 12 to 26 Ä -1) and ii) of liquid neon, near 27 K (for wave-vector transfers 10.4 to 27.6 Ä -1). Neutron time-of-flight chopper spectrometers were employed. Single-particle kinetic energies, £ k , can be obtained from the analysis of the Doppler-broadened recoil spectrum of the target particles. For argon the temperature dependence of £ k can be compared to expectations from theory, from thermodynamic data, and from previous neutron scattering measurements on collective vibrational modes. For liquid neon the wave-vector-transfer dependence of J{y), the longitudinal momentum distribution function, is being analyzed for final-state effects.
Investigations of the Anisotropic Optical Reflectivity of Binary and Ternary Nb-W Oxides Possessing Block-Type Crystal Structure
Authors: Rüscher C. H. , Zimmermann M. , Götte M.
Published: February 2015

We have studied the anisotropic optical properties of binary NbO2.5-δ (0 < δ ≤ 0.083) and ternary Nb18-εW8+εO69 (ε = 0, 1,..., 9) compounds using the polarized regular-reflection method. We observed strong anisotropic behaviour for all reduced phases. The anisotropic effect can be related to the crystallographical structure principle and to the doping of charge carriers by the reduction of oxygen (δ) or substitution of W for Nb (ε) in the binary and ternary oxides, respectively. Our results indicate that the charge carriers are confined to the structural block units. For increasing δ and ε, metal-like properties occur (δ≥ 0.1, ε > 8) in the infinite block direction only.
Experimental Investigation of the Magnetic Fluctuations in a Toroidal Plasma
Authors: Shi-yao Zhu , Chao Zhou , Cheng Wang
Published: February 2015

This paper presents experimental results on the magnetic field fluctuations in the KT-5C tokamak plasma, including magnetic field fluctuation frequency spectra and the radial profile of the fluctuation amplitudes. These results show that the low frequency components are dominant for the magnetic field fluctuation signals, and that the magnetic field fluctuation levels decrease towards the edge of the plasma. A remarkable influence of the gas puffing level on the amplitude of the magnetic field fluctuations was observed.
The Repulsive Potentials in Alkali Halide Molecules
Authors: Sinistri C. , Margheritis C.
Published: February 2015

On the basis of literature values of various spectroscopic quantities, the "experimental" five derivatives (1st to 5th) of the repulsive functions at the equilibrium distance were evaluated for the 20 alkali halide molecules, retaining the truncated Rittner model for the attractive forces. A self-con-sistency test showed that the used experimental values are reliable.

Different analytical forms of the repulsive potential were then critically evaluated by comparison with the experimental derivatives. The repulsive functions were characterized by two, three, four or five empirical parameters. It has been shown that only functions with at least three parameters are sufficiently accurate to reproduce spectroscopic quantities such as ße and γe : the classical two parameter functions appeared too crude in this context.
Enumeration of Chemical Isomers of Polycyclic Conjugated Hydrocarbons with Different Ring Sizes
Authors: Brunvoll J. , Cyvin B. N. , Cyvin S. J.
Published: February 2015

Polygonal systems, corresponding to completely condensed polycyclic conjugated hydrocarbons with arbitrary ring sizes, are studied. For all the cases up to four rings inclusive, the numbers of CnHS isomers are reported, as well as for some classes of the systems with five rings. Explicit combinatorial expressions and the solutions in terms of generating functions are given in some cases. These solutions were corroborated and extended by computer programming. Chemical applications are reported with references to hydrocarbons which are known in organic chemistry.
The Maximum Number of Kekule Structures of Cata-condensed Polyhexes
Authors: Hansen Pierre , Zheng Maolin
Published: February 2015

Let H denote a simply-connected cata-condensed polyhex. It is shown that if H has three hexagons in a row it does not have a maximum number of Kekulé structures. Otherwise, its number of Kekulé structures is equal to its number of sets of disjoint hexagons (including the empty set). These results lead to an efficient algorithm to determine simply-connected cata-condensed polyhexes with a maximum number of Kekulé structures. A table of such values of H with up to 100 hexagons is provided.
Nonintegrable Stadium Billiard seen as Mirror Cabinet
Authors: Kruelle C. A. , Kittel A. , Huebener R. P.
Published: February 2015

The Bunimovich stadium billiard is treated as a mirror cabinet seen from inside. The resulting system of virtual images of the mirror walls reveals a fractional structure which corresponds to the chaotic trajectories of light rays or billiard balls inside the stadium.
Diode Laser Spectroscopy of NaD, KD, RbD, and CsD: Determination of the Mass Independent Parameters and Mass Scaling Coefficients of the Alkali Metal Hydrides
Authors: Essig Kay , Urban Rolf-Dieter , Birk Helmut , Jones Harold
Published: February 2015

The infrared spectrum of the monodeuterides of the alkali metals, sodium, potassium, rubidium, and cesium have been measured with a nominal accuracy of ±0.001 cm-1 using a diode laser spectrometer. Spectral lines of both the fundamental and the first hot band were observed for all the deuterides except RbD where only the fundamental was measured. The accuracy of previously published data on KH was also improved.

Combination of these new data with similar results obtained previously for the equivalent monohydrides allowed the determination of a set of mass-independent parameters and mass-scaling coefficients for the hydrides of all of the alkali metals. This has allowed the relative magnitudes of the parameters to be compared for the first time. The results indicate that non-adiabatic effects are most prevalent in CsH.
Inversion of First Kind Volterra Equations: Back to Direct Methods?
Authors: Bilbao Luis E. , Grondona Diana E.
Published: February 2015

Numerical inversion of the first kind Volterra equation (the Abel inversion included) has been extensively studied. Direct methods were probably the first methods used to attempt the inversion. Together with the computer hardware evolution, new methods were devised in order to deal with the inherent problem of this kind of equation, that is, error magnification. Using a large number of data points (several thousands) most methods are difficult to use, specially when the inversion and its error are required on line, that is, while performing the experiments. Further, error propagation (coming from the input data and from the parameters of the problem) is, usually, a difficult task and has not been extensively studied. On the other hand, direct methods together with an adequate filter give good resolution, are fast, and error propagation is easily performed. In this work we used the so called Matrix Method for inverting three different equations, showing how to build the resolvent nucleus and how errors propagate through the solution.
Isomerization of Diphenyl Polyenes. Part VII. The effect of Daylight and Direct Irradiation on the Photoisomerization of Ph-(CH = CH)n-Ph for n = 2, 3, 4 in Poly(vinyl alcohol) Films
Authors: Kawski A. , Kukliński B. , Kubicki A.
Published: February 2015

Photoisomerization of 1,4-diphenyl-1,3-butadiene (DPB), 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,8-diphenyl-1,3,5,7-octatetraene (DPO) in poly(vinyl alcohol) (PVA) films was studied unter daylight and direct irradiation. The most efficient photoisomerization occurs in the DPB molecule, the smallest among the compounds investigated. For the greatest, DPO, molecule no distinct isomerization was observed in daylight and only a temperature effect was noted. Therefore, the DPO molecule in the PVA film heated to 423 K may serve as a fluorescence standard.
Internal Cation Mobilities in the Molten Systems (Ag, Rb)NO3 and (Ag,Cs)NO3 Remeasured by the Klemm Method
Authors: Chou Pao-hwa , Matsuura Haruaki , Okada Isao
Published: February 2015

Internal mobility ratios in the molten binary systems (Ag,Rb)NO3 and (Ag,Cs)NO3 have been measured by Klemm's countercurrent electromigration method at various temperatures and compositions. From these and the available data on the densities and conductivities, the cation internal mobilities b have been calculated. Over the investigated regions of temperature and composition bAg is greater than bRb and bCs . The internal mobility of Ag+ is well expressed by bAg = [A/(V - V0)] • exp(-E/RT), where V is the molar volume of the mixtures, A, V0 , and E being constants nearly independent of the coions. A comparison of the present data with those previously obtained by the EMF method certifies that the Klemm method yields more precise data.
33S Nuclear Hyperfine Structure in the Rotational Spectrum of Thiazole
Authors: Kretschmer U. , Dreizler H.
Published: February 2015

We investigated the 33S nuclear quadrupole coupling of thiazole- 33S in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8529.29268 (70) MHz, B = 5427.47098 MHz, and C = 3315.21676 (26) MHz, quartic centrifugal distortion constants and the quadrupole coupling constants of 33S χaa = 7.1708 (61) MHz and χbb= -26.1749 (69) MHz and of 14N χ aa = -2.7411 (61) MHz and χbb = 0.0767 (69) MHz.
Internal Cation Mobilities in the Molten Binary Systems (Li, Na)Cl and (Na, K)Cl
Authors: Yang Chao-Cheng , Lee Bor-Jih
Published: February 2015

Internal mobility ratios of the two cations in the molten binary systems (Li, Na)Cl and (Na, K)Cl have been measured with Klemm's column method. From these and available data on the densities and conductivities the internal mobilities bLi , bNa and bK have been calculated. In (Li, Na)Cl, bLi is smaller than bNa in the investigated composition and temperature range, and in (Na, K)Cl, the Chemla effect occurs, that is a crossing of the isotherms is observed.

The internal cation mobilities bM are well expressed by the empirical relation

bM = [A/(V-V0)]exp(-E/RT),

where A, E and V0 are constants depending on the cation M and V is the molar volume of the mixture.
Dielectric Relaxation of Liquid Polyethyleneglycol on Addition of Polyvinylpyrrolidone
Authors: Stockhausen M. , Abd-El-Rehim M.
Published: February 2015

The set of relaxation times describing the dynamic dielectric properties of liquid polyethyleneglycol 200 at 20 and 40 °C is found to be practically independent of the admixture of polyvinylpyrrolidone, though the viscosity is appreciably increased. This is compared to the rather similar behaviour of small molecular solvents.
The Room Temperature Dielectric Spectrum of 2,2-Dimethyl-1 -butanol
Authors: Edelmann R. , Würflinger A. , Hornhardt S. v. , Stockhausen M.
Published: February 2015

The dielectric spectrum of the title substance ('neohexanol') in its pure liquid state is reported for 293 K up to 71 GHz and, for a restricted frequency range, also for lower temperatures (down to 253 K). The room temperature spectrum resembles that of alicyclic alcohols, in particular cyclopentanol, with respect to spectral shape, main relaxation time and the relation of the latter to viscosity, which similarity may be connected with the fact that these alcohols are able to form 'plastic crystals'.
Magnetischer Circular Dichroismus (MCD) von cyclischen π-Elektronensystemen mit 4N±1 Elektronen
Authors: Kramer B. , Fleischhauer J.
Published: February 2015

The theory of the magnetic circular dichroism (MCD) of cyclic re-electron systems with 4 N ± 1 electrons, such as the radical anion of [16] annulene, has been investigated in the perimeter model approximation. General solutions and formulas for the calculation of the Faraday parameters A, B, and C are derived analytically. The calculated and measured spectra of the 17 π-electron [16] annulene radical are in good agreement.
Comments Concerning "The Effect of Temperature on the Fluorescence Quenching of Perylene by Tetrachloromethane in Mixtures with Cyclohexane and Benzene"
Authors: Acree William E.
Published: February 2015

An indirect spectrofluorometric probe method is developed for calculating equilibrium constants for formation of heterogeneous solvent-solvent molecular complexes from measured fluorescence emission intensities in select systems that exhibit parabolic-shaped Stern-Volmer quenching plots.
Nonlinear Behavior of Circularly Polarized Laser Beams Propagating through Sodium Vapor
Authors: Röhricht B. , Eschle P. , Dangel S. , Holzner R.
Published: February 2015

A variety of surprising effects arise from the nonlinear light-matter interaction of circularly polarized laser light propagating through sodium vapor. We present experimental evidence for an asymmetry in the absorption of left hand and right hand circularly polarized light as well as for the creation of a collimated light beam of apposite polarization within the light-matter interaction region. Both effects are not yet explained by common theories.
Anomalous Frequency Scaling of a Saddle-Node Bifurcation on a Limit Cycle Disclosed in a Semiconductor Experiment
Authors: Richter R. , Kittel A. , Parisi J.
Published: February 2015

During low-temperature impact ionization breakdown in extrinsic germanium, spontaneous current and voltage oscillations can be observed. The onset of periodic oscillatory behavior is governed by a saddle-node bifurcation on a limit cycle. Besides the well-known square-root law of control parameter dependence, we find a different scaling in the vicinity of the bifurcation point. Such anomalous behavior is reproduced by a simple model approach.
Explicit Realization of Chaos Control in an NMR-Laser Experiment
Authors: Parisi J. , Badii R. , Brun E. , Flepp L. , Reyl C. , Stoop R. , Rössler O. E. , Kittel A. , Richter R.
Published: February 2015

The usefulness of the Ott-Grebogi-Yorke control method is demonstrated by stabilizing a chaotic NMR-laser system around an unstable period-one orbit. We have used a six-dimensional delay-coordinate embedding technique in order to fully determine the stability properties of the orbit controlled. Our analysis yields small time-dependent perturbations of the system quality factor capable to perform real-time control.
Modelling of Instabilities in Coupled Electrochemical and Biochemical Reaction Systems
Authors: Baier Gerold , Sahle Sven , Urban Peter
Published: February 2015

A three-cell model of an enzymatic electrocatalytic experiment is introduced. Inhibition of a Michaelis-Menten type of reaction leads to bistability and oscillations under potentiostatic conditions.
On a Fractal Model for Turbulence
Authors: Peinke Joachim
Published: February 2015

An interpretation of a recently proposed generic model for fractal basin boundaries in terms of a cascade-like model for turbulence is presented. Intermittency effects are shown by the analysis of structure functions and non-Gaussian probability density functions.
Ab initio Study of the Electric Field Gradients in SCl2
Authors: Wang Jiahu , Smith Vedene H
Published: February 2015

The electric field gradients (EFG) in SCl2 have been computed with both self-consistent-field (SCF) and configuration-interaction (Cl) methods. The predicted EFG, along with the nuclear quadrupole moment QN of 35Cl and 37Cl from other sources, allows us to compare theoretical quadrupole coupling constants with new experimental results. The best values obtained agree with the experiment within 3%. It has been found that the principal axis of the coupling tensor does not coincide with the S-Cl internuclear axis, and the tilt angle has been predicted close to that from experiment.
Centrifugal Distortion Analysis and Study of T 2 -Relaxation for l-Type Doublet Transitions of Nitrous Oxide ( 15N2O) by a Microwave Pulse Technique
Authors: Nicolaisen H. W. , Mäder H.
Published: February 2015

We investigated l-type doublet transitions of 15N20 in the first excited state of the degenerate bending vibration v2 with 14 < J < 34. From analysis of the J-dependence of the line center frequencies, the doubling constant q(0) was obtained together with the first and second order centrifugal distortion constants q(1) and q(2) respectively. For the lines in the J-band (4 to 8.2 GHz) and K-band (18 to 26.5 GHz) we have also investigated the pressure broadening due to self-collisions with use of the transient emission technique. The experimental results for the pressure broadening parameter Γp are compared with predictions from binary collision theory, based on the modified Murphy-Boggs perturbative treatment.
The Rotational Spectra of the 32S-, 33S-, and 34S-Isotopomers of Thiophene
Authors: Kretschmer U. , Stahl W. , Dreizler H.
Published: February 2015

The rotational spectra of the 32S-, 34S- and 33S-isotopomers of thiophene have been studied in their natural abundances using microwave Fourier transform spectroscopy. For the 32S-isotopomer the rotational and centrifugal distortion constants were found to be A' = 8041.59407(46) MHz, B' = 5418.26219(17) MHz, C' = 3235.78061(16) MHz, D'J = 0.6967(96) kHz, D'JK = 0.530(14) kHz, D'K = 1.789(49) kHz, δ'K = 0.3067(21) kHz, R'6 = - 0.0738(12) kHz. For the 34S-isotopomer A' = 8041.7055(84) MHz, B'= 5274.1837(23) MHz, C' = 3183.8432(23) MHz, and for the 33S-isotopomer A'= 8041.651 (10) MHz, B' = 5344.2988(15) MHz, C' = 3209.25777(66) MHz with almost the same centrifugal distortion constants were obtained. The 33S-quadrupole coupling constants of the 33S-thiophene are χaa = 6.8610(64) MHz and χbb - χcc = -48.766(11) MHz.
About the Usage of Scaling Parameters in the Scaled Particle Theory of Mixtures of Non-Additive Hard Spheres
Authors: Schaink H. M.
Published: February 2015

A new simple equation of state is derived for symmetric and asymmetric mixtures of non-additive hard spheres. The derivation of the equation of state is reminiscent of the scaled particle theory. However, this method uses two scaling parameters, which depend on the composition of the mixture. As a result, the equation of state presented here approaches in a natural way the limit of the one component fluid. This feature of the present theory stands in sharp contrast to common scaled particle theories for non-additive hard spheres, where the one component limit has an unphysical dependence on the non-additivity. The equation of state can be used for mixtures of particles that differ in size and has a second and a third virial coefficient which are exact up to first order in the non-additivity. The compressibility factors and the demixing densities predicted by the present equation of state are in fairly good agreement which available MC data.
Eine Anmerkung zum langwelligen UV-Übergang in alternierenden und dazu isomeren nichtalternierenden polycyclischen aromatischen Kohlenwasserstoffen
Authors: Zander Maximilian , Friedrichsen Willy
Published: February 2015

Based on the HMO formalism and for an infinite number of carbon centers an analytical solution for the ratio x = ∆ε(HOMO-LUMO)[NAH]/∆c(HOMO-LUMO)[AH] of nonalternant polycyclic aromatic hydrocarbons (NAH) and its respective counterparts (AH) is given. It is shown that generally x ≥ 1, which is in agreement with experimental observations.
Externally Driven Nonlinear Oscillator, PainlevéTest, First Integrals and Lie Symmetries
Authors: Steeb W.-H. , Euler N.
Published: February 2015

For arbitrary constants c1 , c2 and an arbitrary smooth functions f the driven anharmonic oscillator d2u/dt2+c1du/dt + c2u + u3 =f(t) cannot be solved in closed form. We apply the Painleve test to obtain the constraint on the constants c1 , c2 and the function f for which the equation passes the test. We also give the Lie symmetry vector field and first integrals for this equation
Small Oscillations, Sturm Sequences, and Orthogonal Polynomials
Authors: Baake Michael
Published: February 2015

The relation between small oscillations of one-dimensional mechanical n-particle systems and the theory of orthogonal polynomials is investigated. It is shown how the polynomials provide a natural tool to determine the eigenfrequencies and eigencoordinates completely, where the existence of a specific two-termed recurrence formula is essential. Physical and mathematical statements are formulated in terms of the recurrence coefficients which can directly be obtained from the corresponding secular equation. Several results on Sturm sequences and orthogonal polynomials are presented with respect to the treatment of small oscillations. The relation to the numerical treatment of the generalized eigenvalue problem is discussed and further applications to physical problems from quantum mechanics, statistical mechanics, and spin systems are briefly outlined.
A Simplified Algorithm for Finding Partially Invariant Solutions of Quasilinear Systems
Authors: Becker Dirk-A.
Published: February 2015

The method of partially invariant solutions of PDE systems was introduced by Ovsiannikov as a generalization of the classical similarity analysis. It offers a possibility to calculate exact solutions possessing a higher degree of freedom than similarity solutions. Ovsiannikov's algorithm, however, is somewhat hard to apply because one has to deal with three equation systems derived from the original PDE system. By means of the two-dimensional Euler equations, we show how the algorithm can be essentially simplified if classical similarity solutions are already known. Further, we prove a necessary criterion for the simplified algorithm to be senseful.
Ultrasonic Velocity and Absorption in(Li,Ag)NO3, (Na,Ag)NO3,(K,Ag)NO3, (Cs,Ag)NO3, (Li,Rb)NO3, and (Na,Rb)NO3 Melts Measured by the Pulse Transmission Method
Authors: Rejek E. , Richter J. , Stark A. , Vogt M.
Published: February 2015

Ultrasonic velocity and absorption have been measured in molten (Li,Ag)NO3, (Na,Ag)NO3, (K ,Ag)NO3, (Cs,Ag)NO3, (Li,Rb)NO3, and (Na ,Rb)NO3 , and (Na,Rb)NO3 as functions of composition in the tem­perature range 230 to 300 °C. An improved pulse transmission device was applied. The obtained accuracy was 2‰o for the velocity and 2-4% for the absorption data. The ultrasonic velocity and absorption coefficient (25 MHz) were found to depend linearly on temperature. The dependence of the velocity on the mole fraction could be represented by a cubic polynomial. For the absorption values (referred to the square of frequency) a reasonable general dependence on composition could not be given. The adiabatic compressibility of all mixtures has been calculated from the measured sound velocity. The ratio bulk/shear viscosity and the bulk viscosity itself follow from the measured absorption values together with the velocity values. The conclusion from these data is that ultrasonic absorption in the six investigated systems is governed by the bulk viscosity and that structural rearrangements rather than structural relaxation of the molecules, are the reason for high bulk viscosities in ionic melts.
Flash Photolysis Studies of 4-Chloroanisole in Aqueous Solution
Authors: Abd El-Hameed Faten S. M. , Krajnik Paul , Getoff Nikola
Published: February 2015

The photoinduced formation of transients in aqueous 4-chloroanisole (4 ClA), at pH 7 and 9, were studied by conventional flash photolysis. The absorption spectra of various transients in airfree as well as in aqueous solutions saturated with N2O , air or pure oxygen, are presented and discussed.
Effective Boson-Fermion Dynamics for Subfermion Models
Authors: Grimm G.
Published: February 2015

Effective composite particle dynamics can be derived by weak mapping of quantum fields. This method was already applied to derive effective boson or boson-fermion coupling theories from a nonlinear subfermion field. In this paper we present an extension of those calculations to the general group theoretical treatm ent of two-fermion bound states and their coupling to (elementary) fermions within an arbitrary nonlinear spinor-isospinor field model. The resulting effective field equations are com pared with the corresponding phenomenological expressions which for example underly the standard electroweak theory.

PACS 11 .10 - Field theory.

PACS 12.10 - Unified field theories and models.

PACS 12.35 - Composite models of particles.
Anharmonic Self-Consistent Theory of Crystals. II. The 2d and 3d Quartic Crystal Models
Authors: Soulayman S. Sh. , Marti C. Ch. , Guilpin Ch. Ch.
Published: February 2015

In this paper we apply the method developed in part I for describing the crystalline state of two and three dimensional inert gases. For strong anharmonicity of fourth order, the equations of state of these gases are obtained. This way we calculate the thermoelastic properties of two and three dimensional argon, krypton and xenon using the Lennard-Jones potential. The corrections to the Helmholtz free energy and thermodynamic properties due to quantum effects are considered. The results are compared with the available experimental data.
35Cl Nuclear Quadrupole Relaxation in Antimony Trichloride
Authors: Okubo Noriaki , Abe Yoshihito
Published: February 2015

The 35Cl NQR frequency and spin-lattice relaxation time in SbCl3 have been measured between 10 K and the melting point. The relaxation at low temperatures is attributed to the Raman process. A Debye temperature of 141 K and covalencies 0.390 and 0.356 are obtained. The latter values correspond well to those obtained from the NQR frequencies. For the relaxation above 200 K two more mechanisms are considered.
Nuclear Quadrupole Resonance of Antimony in Ln3Sb5O12 Crystals
Authors: Raevsky A. M. , Gukalova A. G. , Semin G. K.
Published: February 2015

Complete 121,123Sb NQR spectra of crystalline rate earth antimonites Ln3Sb5O12 (Ln = La, Nd, Er, Lu) were recorded at 77 K. The quadrupole coupling constants and asymmetry parameters of the electric field gradient were measured. A “lanthanide compression” effect on the antimony NQR was observed. Using relations found for the antimonites under study, the Sb spectral parameters of other lanthanide compounds can be predicted.
Internal Cation Mobilities in Molten (Ca,Ba)Cl2
Authors: Matsuura Haruaki , Okada Isao
Published: February 2015

Internal cation mobility ratios in molten (Ca, Ba)Cl2 have been measured by the Klemm method for χBa (mole fraction of barium chloride) = 0.25 -0.51 at 973 K and χBa = 0 -0.61 at 1073 K. From these and available data on the densities and conductivities the internal cation mobilities b have been calculated, assuming additivity of the molar volume. Although bCa in pure CaCl2 is greater than bBa in pure BaCl2, bCa is smaller than bBa in all the investigated mixtures at the respective temperatures. With increasing molar volume at constant temperature both bCa and bBa decrease. Since the profile of the isotherms is similar to that for the binary monovalent chloride systems so far studied, monoatomic ionic species are assumed to carry the current also in the alkaline earth chloride melts.
The Dielectric and Dilatometric Single Crystal Studies of Phase Transitions in a New Member of Family of Halogenoantimonates(III) [C(NH2)3l2SbCl5· [C(NH2)3]Cl
Authors: Zaleski J. , Jakubas R.
Published: February 2015

The results of dielectric, dilatometric and DSC studies on a new member of the family of alkylammonium halogenoantimonates ([(C(NH2)3]2SbCl5 • [(C(NH2)3]Cl) are presented. This compound undergoes three phase transitions at 146 K, 162 K, and 366 K. The two low temperature transitions are suggested to be of the displacive type and the high temperature one of the order-disorder type. The character of temperature changes of the electric permittivity at the lowest temperature transition suggest a polar phase below the transition temperature.