bluuebunny/crossref_metadata_2025 huggingface dataset:
ClNO-katalysierter ClNO2-Zerfall in 1-Chlorperfluorheptan / ClNO-catalysed decomposition of ClNO2 in 1-chloroperfluoroheptane
Authors: Knauth H.-D. , Martin H. , Schlapkohl H.
Published: February 2015

The thermal decomposition of ClNO2 in the presence of ClNO was investigated between 353 K and 373 K in solution (C7F15Cl) by spectral photometric means. ClNO catalyses the decomposition by the steps

The Arrhenius parameters for the rate determining step of the catalysed reaction was found to be

A/cm3 mol-1 s-1 = 1012.17±0.32; E/kJ mol-1 = 79.5±2.1.
Third Virial Coefficients for Helium
Authors: Caligaris R. E. , Grangel J . C.
Published: February 2015

Third virial coefficient for helium is calculated using the realistic Beck pair potential. The first quantum correction and the triple-dipole dispersion interaction are included. The results are compared with experimental data and with theoretical values obtained using the MDD-2 pair potential.
Spectroscopic Observation Radiative Recombination of Ground State Oxygen Atoms
Authors: Hoffmann H . , Neiger M.
Published: February 2015

Measurements of uv-radiation emitted from a low current oxygen arc plasma show continuous emission, which can be attributed to radiative molecular recombination of ground state oxygen atoms.
Zur Korrektur von Einteilchenenergien mit statistischen Korrelationspotentialen / On Correcting One-Particle-Energies by Statistical Correlation Potentials
Authors: Schneider Wolfgang J .
Published: February 2015

HF-energies of outer atomic electrons have been correc­ted for correlation by Gombas’ statistical potential Vμ
K using his well known interpolation formula for the correl­ation energy of an electron gas as a function of density ρ. The choice of statistical electron distributions for ρ is ad­equate since in this way features in the derivation of Vμ
K are simulated, leading to good correction values.
Kinetics of the Reversible Transformation of 2,3-Dioxogulonic Acid into its Enol as a Function of the pH of the Medium
Authors: Zuluaga J. , Martínez P.
Published: February 2015

2,3-dioxogulonic acid and the disodium salt of its enol were synthesised, isolated and identified both chemically and spectroscopically. A kinetic study was carried out on its equilibrium by means of the “stopped flow” method for rapid processes, and the rate constants for the forward and backward reaction were determined as a function of the pH of the medium. The kinetic coefficients involved, equilibrium constant and Gibbs free energies were also determined.
Optical Spectra of Chlorophyll a and b Molecules and Complexes in PMMA and MTHF
Authors: Hägele W. , Schmid D. , Drissler F. , Nauš J. , Wolf H. C.
Published: February 2015

The optical spectra of chlorophyll a and chlorophyll b in PMMA and MTHF were studied over a wide range of concentration (8 X 10-6-1 X 10-3 mole/l in PMMA, and 10-6-10-1 mole/l in MTHF). In the absorption spectra it is possible to identify bands which originate from chlorophyll disolvates and chlorophyll monosolvates in MTHF as well as bands which are most probably due to isolated chlorophyll molecules in PMMA. In high-concentration samples of chlorophyll in MTHF some bands may be assigned to aggregates, but based on optical results only, no particular model can be proposed. The emission spectra are strongly influenced by reabsorption and energy transfer processes. However, the so-called Qy band of isolated molecules in PMMA and of chlorophyll monosolvates in MTHF as well as the Qx and the Qy bands of chlorophyll disolvates in MTHF can be identified unequivocally in the fluorescence spectra.
Notizen:Schwingungseigenschaften des TeO4
2- -Ions/ Vibrational Properties of the TeO4
2--Ion
Authors: Baran Enrique J.
Published: February 2015

A complete assignment of the fundamental vibrations of the tetrahedral TeO4
2- ion is proposed and its principal force constants have been calculated using the modified valence force field. Mean amplitudes of vibration and bond orders are also estimated. The results are briefly discussed and some comparisons with related species are made.
Notizen:Electron Diffraction Investigation of the Molecular Structure of Trifluoromethyl Sulphonyl Chloride
Authors: Brunvoll Jon , Hargittai István , Kolonits Mária
Published: February 2015

An electron diffraction investigation yielded the following geometric parameters for trifluoromethyl sulphonyl chloride rg(C-F ) 1.326(4), rg(S=0 ) 1.416(7), rg(S-Cl) 2.016(5), rg(S-C) 1.857(6) Å, ∢ O= S - C 108.3(7)°, ∢ C-S-Cl 98.7(4)°, ∢ O = S = O 122.4(10),° ∢ O = S - Cl 108.3(3)°, ∢ F -C-F 109.9(3)°. The S - C bond is in CF3SO2Cl by almost 0.1 Å longer than in CH3SO2Cl.
Notizen:Einige Bemerkungen zur Stabilität von WO2F2 / Remark on the stability of WO2F2
Authors: Bruijn J. de , Dettingmeijer J. H.
Published: February 2015

Based on equilibrium calculations on the W-O-F system [6], in which WO2F2 was found to be the predominant low temperature species, an attempt was made to synthesize WO2F2 from WO2 + NF3.

However, yields of WOF4 instead of WO2F2 were obtained. This discrepancy between theory and experiment is shown to be due to an error in the estimation of the thermodynamic data of WO2F2 [1].
Diffusion Controlled Effective Reaction Rate for a Surface Reaction with Orientational Selectivity
Authors: Hess Siegfried
Published: February 2015

The influence of the orientational selectivity of a chemical reaction on the diffusion controlled effective reaction rate is investigated theoretically for the following situation: Nonspherical molecules with random orientation are put into a chemically inert solution at a plane which is a certain distance away from the parallel reaction plane. The reaction frequency at the surface shall depend on the orientation of the figure axis of a molecule relative to the normal of the reaction plane. With a special choice for the orientational dependence of the surface reaction, a continued fraction expansion is derived for the diffusion controlled effective reaction rate. This quantity is discussed and displayed graphically as function of the relevant parameters.
Error Bounds of Continued Fractions for Complex Transport Coefficients and Spectral Functions
Authors: Hänggi P.
Published: February 2015

We study the calculation of complex transport coefficients x (ω) and power spectra in terms of complex continued fractions. In particular, we establish classes of dynamical equilibrium and non-equilibrium systems for which we can obtain a posteriori bounds for the truncation error | x (ω) - x(n)(ω)| ≦ c (ω) | x(n)(ω) - x(n-1)(ω)| when the transport coefficient is approximated by its n-th continued fraction approximant x(n)(ω).
The Non-linear Relation between Average Size and Perimeter of Lattice Animals
Authors: Duarte J. A. M. S.
Published: February 2015

For
t, the average number of sites in two dimensional cluster configurations (“lattice animals”) with a fixed perimeter t, an asymptotic dependence of the form
t α t3/2 is found. This dependence, for which a scaling theory is still missing, is particularly accurate for the triangular lattice when t is measured by the number of broken bonds.
General Formulation of the (111,1̄11) Neutron Three Beam Case
Authors: Treimer W.
Published: February 2015

A formalism developed in a previous paper [1] is now applied in a general way to the special three beam case (111, 1̄11). The restriction for the incoming wave to be located in the symmetry plane is abolished. The individual behavior of the dispersion surfaces and reflection curves are determined and discussed.
Theoretical Study of Time Correlation Functions in a Discrete Chaotic Process
Authors: Fujisaka Hirokazu , Yamada Tomoji
Published: February 2015

One-dimensional discrete chaotic processes are studied from a statistical-dynamical point of view. A set of equations which describe the behavior of the time correlation functions is derived with the aid of Mori’s projector formalism. A condition under which a process is Markoffian is obtained, and an approximate method is developed for a non-Markoffian process. As an illustration, a time correlation function for a simple system is calculated and the comparison with results of computer simulations is made. The relation between the instability of a trajectory and the characteristic time of chaotic motions is also discussed.
Effect of Conductivity on Magneto-Gravitational Instability and Suspended Particles
Authors: Chhajlani R. K. , Vashistha P. , Bhand S. C.
Published: February 2015

The self gravitational instability of an infinite homogeneous magnetized gas-particle medium in the presence of suspended particles is investigated. The conductivity of the medium is assumed to be finite. The dispersion relation is obtained for such a medium. It is found that in the presence of suspended particles a sufficient condition of instability is obtained by Jeans’ criterion for a self gravitating magnetized conducting gas-particle medium.
“Constant-Volume Alloy” Formulation of Enthalpy of Mixing for Metallic Systems
Authors: Leribaux H. R. , Desre P. J.
Published: February 2015

We present an exact statistical thermodynamic expression for the partial enthalpy of mixing for metals which avoids the problems of evaluating the large internal energy of the pure metals from the plasma state. This method is applied to the homovalent alloys Al-Ga, Al-In and Al-Tl. The results show clearly the tendency towards a critical mixing point in these systems when using a pseudopotential theory for these metals. An estimate for the critical point of the Al-Tl system and reasonably correct values for the partial enthalpies at infinite dilution are obtained.
Microwave Spectra of Dimethylether (CH3)2O and (CD3)2O in Excited Torsional States
Authors: Lutz H. , Dreizler H.
Published: February 2015

The rotational spectra of the torsional excited states v̅n = 11,12,21, 22, 23 have been measured and assigned. The torsional fine structure was used to determine the coefficients V3 and V' 12 of the hindering potential. For (CH3)2O : V3 = 2618 ± 4 cal/mole, V'12 = 18 ± 8 cal/mole, for (CD3)2O : V3 = 2572 ± 6 cal/mole, V'12 = 29 ± 12 cal/mole, V12 was correlated to V3 .
A Cluster Expansion Formalism for Direct Calculation of Ionisation Potential and Excitation Energy of Many Electron Systems Using H-F Ground State as Vacuum
Authors: Mukherjee D. , Mukhopadhyay A. , Moitra R. K.
Published: February 2015

In this note, the authors’ recently developed non-perturbative open-shell theory is adapted for direct calculation o f ionisation potential and excitation energy of m any-electron systems. The H -F ground state is used as the “vacuum ” or “ core” in order to achieve a transparent separation o f the ground state energy. An application to a simple 4 π-electron system is discussed as an illustration o f the workability of the theory.
Measurement of Fluorescence Lifetimes of Coumarin Laser Dyes with a Mode-Locked Krypton Ion Laser
Authors: Richardson J. H. , Steinmetz L. L. , Deutscher S. B. , Bookless W. A. , Schmelzinger W. L.
Published: February 2015

The fluorescence lifetime of four coumarin laser dyes (C-7, C-30, C-102, and C-120) were measured in three different solvents (methanol, ethanol and water) a t dilute and lasing concentrations. The lifetime generally decreases for the more hydrophobic dyes as the solvent polarity increases. There is little change with concentration due to the large Stokes shift.
Properties of [N,N′-di(n-propyl)-4,4′-bipyridylium]2+ (7,7,8,8,-Tetracyanoquinodimethane)4
2–
Authors: Ashwell G. J. , Diaconu I. , Eley D. D. , Wallwork S. C. , Willis M. R.
Published: February 2015

The crystal structure and electrical properties of [N,N′-di(n-propyl)-4,4′-bipyridylium]2+ -(7,7,8,8-tetracyanoquinodimethane)4
2-, (DPrBP)2+(TCNQ)4
2-, are reported. The complex is monoclinic with the space group P21/c and lattice constants a = 13.334(1), b = 25.954(3), c = 7.877(1) Å, β = 93.66°, Z = 2. The single crystal dc resistivities at 300 K along a, b and c are 3300, 200 and 800 Ω cm respectively with activation energies of 0.36, 0.22 and 0.30 eV. The existence of a hopping mechanism in addition to a frequency independent conduction process is indicated by a. c. conductivity data obtained on a compressed disc between 10 and 105 Hz.
Optical and ODMR Investigations of the Lowest Excited Triplet State of Dinaphtho-(2′.3′:1.2); (2″.3″:6.7)-pyrene
Authors: Bräuchle Chr. , Kabza H. , Voitländer J.
Published: February 2015

On the basis of the phosphorescence spectrum of dinaphtho-(2′.3′:1.2); (2″.3″:6.7)-pyrene in n-dodecane (Shpolskii matrix) at T = 1.3 K a site and vibrational analysis was performed. With the help of ODMR measurements the symmetries of the vibrational bands were determined. In this way for most of the normal modes an assignment of the type of vibration became feasible. Because of their different zero-field splittings (ZFS) five sites could be identified. The signs of the ZFS parameters as well as the kinetic rate constants of population and depopulation of the zero-field levels (ZFL) of T1 were determined. Like the ZFS the kinetic rate constants too were different for each site reflecting different interaction of the molecules with the host matrix. Radiative and radiationless processes are discussed in terms of spin-orbit coupling (SOC).
Clusius’ Separation Column as a Reactor to Produce Highly Concentrated Hydrogen
Authors: Hirota Kozo , Aizawa Kazuo , Nishizawa Tsuneyuki
Published: February 2015

A Clusius’ separation column of hot wall catalytic activity was applied as a reactor to produce highly concentrated hydrogen. Satisfactory results are obtained in the decomposition of hydrogen sulfide and the conversion of carbon monoxide with water.
The Langmuir-Hinshelwood Reaction between Oxygen and CO at Ir(111) Surfaces
Authors: Küppers J. , Plagge A.
Published: February 2015

The reaction of oxygen and CO to form CO2 has been investigated using an Ir (111) surface as an acting catalyst. Both instationary and stationary reaction processes have been established via separate gas exposing techniques. The instationary reaction process, achieved from coadsorbed CO and O which per se is an LH reaction is found to be controlled by an apparent activation energy of 10.7 kcal/mole. The stationary reaction with both CO and O2 continuously present in the gas phase has been simulated using a proper computer program, involving both LH and ER reaction steps. By comparison with experimental results, close agreement is found when ruling out any ER reaction step from the reaction path.
δ13C Record in an Undisturbed Forest Soil
Authors: Schleser G. H. , Pohling R. , Meyer B.
Published: February 2015

13C/12C variations of organic carbon have been investigated in an undisturbed forest soil with perched surface water. The measurements reveal a very distinct decrease of the 13C-content with increasing depth of the soil horizons. Within 20 cm the δ13C-value is depleted by 1.5/0
00. At present it is however not possible to verify, whether this behaviour is characteristic for undisturbed soils in general.
Variational Principle for Slow Viscous Flow of Fluids with Anisotropic and Spatially Inhomogeneous Viscosity, Upper and Lower Bounds on the Frictional Force and Torque
Authors: Hess Siegfried
Published: February 2015

The frictional force and torque excerted by a fluid on a solid body which performs a slow translational or rotational motion is related to the rate of entropy production. Starting from the Navier-Stokes equation, a variational principle is derived for this quantity. Provided that the antisymmetric part of the viscosity tensor is smaller than its symmetric part upper and lower bounds on the force and torque are established. These bounds can be calculated with certain trial functions for the flow velocity field
Die spezifische Wärme der zweiten Relaxationsstufe der Essigsäure
Authors: Asenbaum A.
Published: February 2015

The The relaxation time σv in liquid acetic acid was measured by Brillouin scattering for temperatures in the range between 20 °C and 60 °C. At 20 °C σv is equal to 56,2 ps corresponding to a relaxation frequency fR2 of 2,51 GHz. fR2 is increasing with increasing temperature and there-fore shows the same behaviour as the first relaxation frequency fR1 measured by Lamb and Pinkerton. From σv and the hypersound-velocity and hypersound damping data the relaxing specific heat ci2 has been calculated (ci2 = 0,125 cal/g K at 20 °C). In contrast to the specific heat ci1 of the first relaxing step of acetic acid ci2 seems to be temperature independent within the experimental error
Polarized Crystal Absorption Spectra of Pd(II) and Pt(II) Tetrahalo and Tetrathiocyanato Complexes
Authors: Tuszynski W. , Gliemann G.
Published: February 2015

Single crystal absorption spectra of tetrachloro, tetrabromo, and tetrathiocyanato complexes of Pd(II) and Pt(II) have been measured in the visible and near-ultraviolet region at temperatures between 10 K and 295 K. A spectral assignment of the observed d-d transitions based on ligand field theoretical calculations including electron-electron interaction and spin-orbit coupling is proposed which is consistent for all the systems investigated
Laser Power Noise Measurements on a Cataphoretic He-Cd+ Laser
Authors: Neiger M. , Nemec V.
Published: February 2015

Laser power noise has been measured on a cataphoretic He-Cd+ laser. Care was taken especially to stabilize the temperature of the external cadmium source and to thermally insulate the discharge capillary. It was found that high and low noise operating regions exist with noise values below 1% rms at power levels up to 80% of the maximum obtainable ones
Unitarization in Nonlinear Spinor Field Quantum Theory
Authors: Stumpf H. , Scheerer K.
Published: February 2015

Heisenberg performed a dipole ghost regularization of the Lee-model and a subsequent uni-tarization of the corresponding state space. If this method is transferred to the relativistic non-linear spinor field model, insoluble difficulties appear as long as no explicit state representations are used. In preceding papers such state representations for the spinor field have been derived and in the present paper it is demonstrated how they can be successfully used to perform the relativistic analogon to Heisenberg's Lee-model unitarization. As the state representations have to be derived by construction, the method is demonstrated for the two particle fermion sector which is sufficiently well-known.
Schwingungsspektrum von CSFCl Vollständiger Satz von Anharmonizitätskonstanten; harmonische Schwingungsfre- quenzen ; korrigiertes harmonisches inneres Kraftfeld / Vibration Spectrum of CSFCl
Authors: Hamm R.
Published: February 2015

The measurement of the infrared spectrum of CSFCl over a large spectral range from 300 cm -1 to 4000 cm -1 was done with a special cell allowing a path-length of up to 20 m. In that way it was possible to obtain a full set of anharmonicity constants by exploring combination and over-tone bands. Hereby the vibration frequencies of the fundamentals could be corrected for anharmonicity. The corrected values of the main species and of a further isotopic species were used to calculate the internal harmonic force field. The harmonic vibration correction terms needed for the determination of the rz-structure turned out to be changed only by 1% as com-pared with those values that were infered from a preliminary force field formerly.
Ground State Wave Function and Superexchange Interaction in CuCl2 · 2NC 5 H 5
Authors: Amoretti G. , Varacca V. , Vera A.
Published: February 2015

A model of superexchange, which takes into account the contributions of the polar states, is applied to the case of CuCl2 · 2 NC5H5. As pointed out in a preceding paper, the experimental exchange constant Jeff can be fitted in a reasonable range of parameters of the ground state wave function, which, on the other hand, is tested by means of ESR experimental data. The results are compared with those obtained for CuCl2 · 2 H2O and the approximations introduced are discussed and justified.
Spin-Gitter-Relaxationszeit T1 von Nitrilkohlenstoffen / Spin-Lattice-Relaxation Time T1 of Nitrile Carbon-atoms
Authors: Sterk H. , Kalcher J. , Kollenz G. , Waldenberger H.
Published: February 2015

It is shown that in almost all nitrile carbon-atoms T1 depends first of all on the inter-and/or intramolecular dipol-dipol-relaxation mechanism. Only acetonitrile, as is already known, shows a remarkable dependence on the spin-rotation-relaxation mechanism. This influence is strongly decreasing with an increasing number of atoms, specially hydrogen atoms, in the molecule. The significance of the correlation time r is discussed extensively and the experimental results are verified by calculation of T1 using the viscosity and the inertial moments as parameters.
On the Deconvolution of Measured Curves with Measured Apparatus Functions and the Information Content of Curves
Authors: Hühnermann H. , Menzel N.
Published: February 2015

A general problem in natural science is the analysis of experimental curves, which are quite often distorted due to the measuring devices. However, in some cases the apparatus function can be measured separately so that one can hope to restore the original curve by means of a suited mathematical procedure. Based on experimental examples taken from atomic physics and without complicated mathematical formalism, we show possibilities and limitations of the deconvolution of measured curves with measured apparatus functions. The choice of the Fourier transformation algorithm makes it possible to compute the information content of curves quite easily. This may be used to optimize the performance of an experiment.
Generation of a Steady-State Overdense Plasma by Microwaves near the Dipole Resonance of a Coaxial Discharge Device
Authors: Kampmann B.
Published: February 2015

At electron densities above the dipole resonance of a coaxial plasma-waveguide-system a steadystate discharge has been generated. The measured complex wave vector is compared to the calculated electromagnetic dispersion relation and allows conclusions concerning electron densities as well as relative electron density profiles. Attention is paid to the occurrence of parametric decay
Plasmaparameter in der Anfangsphase eines Q-switch-Laser-Funkens in Stickstoff / Plasmaparameters in the Initial Stages of Plasmas produced by a Q-switch Laser in Nitrogen
Authors: Meyer I. , Stritzke P.
Published: February 2015

An experimental investigation of the breakdown in Nitrogen at 1.5 atm under intense radiation from a Q-switched Nd: glass Laser (peak power 1 MW) is presented. Two main techniques were used: Spectroscopic methods gave information on the axial and radial growth of the emitted light intensities. The image converter streak technique and Schlieren photography were used to investigate the propagation of the shock waves. This paper includes the radial and temporal distribution of the plasmaparameters temperature and electron density in the focus region, but also in distances of 240 /μm from the focus. It was found that local thermal equilibrium is established within about 10-14 ns, but only in a small part of the spark
The Rotational Zeeman Effect of Methyl-and Silylbromide
Authors: Dössel K.-F. , Sutter D. H.
Published: February 2015

The rotational Zeeman effect of the J→J' = 0→1, K = 0 transition has been investigated for CH3
81Br and SiH3
81Br under high resolution. The shielding constant for the 81Br-nucleus in these molecules has been determined from the spectra and is compared to the values calculated from the spin-rotation coupling constants. The sign of the electric dipole moment in SiHßBr is shown to be ⊕H3SiBr⊕. From the Zeeman effect of two K ≠ 0 transitions of SiH3Br, g|| is determined to be negative for SiHaBr, in contrast to CH3Br, where g|| is positive
The Microwave Spectrum of Silylisothiocyanate, SiH 3 NCS III. The Rotational Zeeman Effect
Authors: Dössel K.-F. , Sutter D. H.
Published: February 2015

The rotational Zeeman effect has been investigated for four different isotopic species of SiH3NCS. From the observed g-values we have determined the sign of the electric dipole-moment in SiH3NCS to be ⊕H3SiNCS⊖. Thus the previous choice of sign which had been based on the results of a quantum chemical CNDO/2 calculation had to be revised. For the master isotope g⊥, g|| and (x⊥-X||) have been determined and were used to calculate the molecular electric quadrupole moment, the paramagnetic and diamagnetic susceptibilities and the second moments of the electronic charge distribution
Eine CNDO/2-INDO-Studie zum Mechanismus der thermischen Dimerisierung von Dimethylketen / A CN DO/2-IN DO-Study of the Mechanism of the Thermal Dimerization of Dimethylketene
Authors: Schleker Wolfgang , Fleischhauer Jörg
Published: February 2015

The thermal dimerization of dimethylketene leads to a cyclobutane-1,3-dione. The [π2S + π2S]- and [π2S + π2a] -reaction routes are examined by CNDO/2- and INDO-calculations. It is shown that the latter is lower in activation energy. The structure of a possible transition state in a nonconcerted mechanism is discussed. Viewpoints like the [π2a + π2a]-way, the biradical mechanism, and the formation of 1,2-diones are considered
Heavy Atom-and Deuterium Isotope Effect in Bis-(Phenylethinyl)-Mercury
Authors: Weinzierl G. , Friedrich J. , Griebel R.
Published: February 2015

The influence of mercury as a heavy atom on the spin orbit coupling is investigated in bis- (phenylethinyl)-mercury and its deuterated derivative. From the experimental results we draw the following conclusions: a) the symmetry of the molecule is D2, b) the large spin orbit coupling of the mercury atom is introduced via dπ pπ-interaction, c) local σ π-transitions and vibronic coupling are of no importance, d) the weak deuterium effect in the radiationless decay is a consequence of the fact that the triple bonds act as strong energy acceptors
Broadening Effects of the 632.8 nm Nel Line Due to a Helium-Neon Mixture
Authors: Bielski A. , Darowicki H. , Szudy J.
Published: February 2015

An experimental test of the additivity of perturbation energies produced by collisions of the radiating atom with perturbers is made by measuring the Lorentzian half-width of the 632.8 nm line of Nel under various pressures and with various concentration ratios of a mixture of Ne and He. The Lorentzian half-width produced by the mixture is found to be the sum of half-widths due to each component gas
Winfree Meandering in a 2-Dimensional 2-Variable Excitable Medium
Authors: Rössler . E. , Kahlert C.
Published: February 2015

Two-dimensional excitable media, for example the excitable version of the Belousov-Zhabotin-sky reaction, are capable of forming spiral-shaped self-sustaining rotating wave patterns (rotors). In order to explain Winfree's experimental observation of an irregular "meandering" of the rotor's core region, we present a numerical simulation of a continuous, two-variable excitable medium in two space dimensions. Two phenomena occur: 1) an irregular motion of the rotor's core; 2) a non-stationary peak inside the core region. Thus, "meandering" is obtained, together with a new phenomenon, the "peak". A sufficient condition for both phenomena is that the underlying (local) system be stiff, that is, admit two time scales for its approximate description. In this case, (1) the "reaching distance" of diffusion is small as compared with the core's radius, and (2) rotation symmetry of the core implies a gradation in local frequencies (increase toward the center), supposing radial decoupling. We propose that both constraints act together to induce a spontaneous breakdown of rotation symmetry under an increase of stiffness. Immediately (or soon) thereafter, the core is no longer synchronized by the wave circling around it; instead, excitation from the surrounding wave penetrates the core along a new path from time to time, causing a non-repetitive short-cut.
Electron Energy Distribution Functions of Hydrogen: The Effect of Superelastic Vibrational Collisions and of the Dissociation Process
Authors: Capitelli M. , Dilonardo M.
Published: February 2015

Electron energy distribution functions (EDF) of molecular H2 have been calculated by numerically solving the Boltzmann equation including all the inelastic processes with the addition of superelastic vibrational collisions and of the hydrogen atoms coming from the dissociation process. The population densities of the vibrational levels have been obtained both by assuming a Boltz-mann population at a vibrational temperature different from the translational one and by solving a system of vibrational master equations coupled to the Boltzmann equation.

The results, which have been compared with those corresponding to a vibrationally cold molecular gas, show that the inclusion of superelastic collisions and of the parent atoms affects the EDF tails without strongly modifying the EDF bulk. As a consequence the quantities affected by the EDF bulk, such as average and characteristic energies, drift velocity, 0-1 vibrational excitation rate are not too much affected by the inclusion of superelastic vibrational collisions and of parent atoms, while a strong influence is observed on the dissociation and ionization rate coefficients which depend on the EDF tail.

Calculated dissociation rates, obtained by EDF's which take into account both the presence of vibrationally excited molecules and hydrogen atoms, are in satisfactory agreement with experimental results.
Enthalpies of Mixing for the Liquid System Formic Acid + Acetic Acid
Authors: Haase R. , Jansen H.-J. , Puder K. , Winter B.
Published: February 2015

After a short description of the evaluation of the calorimetric measurements, we give the results for the enthalpies of mixing in the liquid system formic acid + acetic acid. The molar excess enthalpy H̄E has been determined as a function of the mole fraction x of acetic acid at 18 °C, 20 °C, 25 °C, 30 °C, and 40 °C. The function H̄E (x) is always positive and nearly symmetric (with a maximum at about x = 0.5) and increases with increasing temperature. A three-parameter fit of the function H̄E (x) has been achieved for each temperature.
Das UV/VIS-Absorptionsspektrum des 9.9′-Dianthryl-disulfids / The UV /VIS Absorption Spectrum of 9,9′-Dianthryl disulphide
Authors: Zander M. , Zellerhoff R. B.
Published: February 2015

9,9′-Dianthryl disulphide is the first example studied for a diaryl disulphide whose uv/vis absorption spectrum exhibits a distinct vibrational structure whereas the formerly investigated spectra of diphenyl disulphide and the isomeric dinaphthyl disulphides are characterized by the complete lack of vibrational structure. Different interpretations have been given in the literature for this particular property of the diphenyl disulphide and dinaphthyl disulphide spectra. The long wave-length region of the dianthryl disulphide spectrum is interpreted with the assumption of three electronic transitions. Two of them are localized in the anthracene or dithio anthracene chromophore, respectively, whereas the third transition is assumed to be non-localized including the whole system with the S-S bridge acting as a conjugative (butadienoid) link. This assignment is consistent with a pπ-model without pπ/dπ-participation in agreement with results of photoelectron spectral investigations on disulphides reported in the literature.
On the Applicability of Redington's Method of Determination of Force Field to Bent XYZ Type Systems
Authors: Namasivayam R. , Mayilavelan S.
Published: February 2015

Force fields of NSF, NSCl, NSBr, SSO, HCO, HOF, HOCl, HOBr and HOI have been computed using Redington’s method. The angle parameters φ12, φ13 and φ23 are fixed through Fsteep critical point solution. The parametrised eigenvector matrices obtained are found to possess the properties predicted by Peacock et al. Mean amplitudes of vibration, Coriolis coupling constants, inertia defects and centrifugal distortion constants have also been calculated and compared with literature values. Redington’s approach is found to reproduce all the molecular constants with accuracies comparable with conventional methods.
An Analysis of Lattice Dynamical Angular Force Models for Body Centered Cubic Metals
Authors: Khanna R. N. , Rathore R. P. S.
Published: February 2015

Present angular force models for lattice dynamical behaviour of body centered cubic (bcc) metals have been analysed for the satisfaction of rotational invariance and general equilibrium conditions. It has been found that most of the angular force models (except that due to Clark et al.) are deficient and leave the lattice under stress. Further it has been inferred that either the axially symmetric or the central pair potential schemes, incorporating the concept of electron pressure, provide the realistic picture of lattice excitations in metals.
Elektronisches Resonanz-Raman-Spektrum von ((C2H5)4N)2[ReI6]/ Electronic Resonance-Raman Spectrum of ((C2H5)4N)2[ReI6]
Authors: Homborg H.
Published: February 2015

The electronic Raman spectrum of hexaiodorhenate (IV) has been measured at 80 K. Under resonance-Raman conditions an enhancement of the Raman intensity occured for the totally symmetric a1g -vibrational mode coupled to the electronic transition Γ8(4A2g) → Γ8(2T1g) .
Measures on Operational Logics
Authors: Bugajski Slawomir
Published: February 2015

It is demonstrated, that any measure on effects is generated by a state, whereas a similar statement for operations is not true.
IR-Active Phonons of Boron and Boron Carbide
Authors: Binnenbruck H. , Werheit H.
Published: February 2015

The possible IR- and Raman-active phonons of α-boron. β-boron, and boron carbide have been obtained by group theoretical methods. Reflectivity and absorption measurements in the spectral range from 10 to 1450 cm-1 and a classical dispersion analysis yield the entire spectra of the anisotropic optical constants in the lattice vibration range of β-boron and beyond. From the reflectivity spectrum of boron carbide the resonance frequencies of the phonons and estimated values of their other characteristic values have been derived. The absorption spectrum of amor­phous boron has been included in the discussion. - Certain frequency ranges can be attributed to vibrations of the icosahedra split in the crystal field. Single vibrations with E∥c displaced to higher frequencies are attributted to the central atoms in the unit cells of β-boron and boron carbide. The phonon shift depending on temperature can be described by the Grüneisen shift. Three- and four-phonon processes are necessary to describe the temperature dependent damping constants of the lattice vibrations.
On the Application of Neutron Small Angle Scattering to the Study of Fluctuations Near the Liquid-liquid Critical Point in Binary Mixtures
Authors: Damay P. , Chieux P.
Published: February 2015

A comparative survey is made of the neutron and light scattering techniques as applied to structural investigations in the vicinity of critical points in fluids. For neutron scattering as applied to fluctuations in binary mixtures, some criteria for a good contrast in order to optimize the scattering parameters such as the isotopic composition or the concentration are considered. This leads us to show how to write the partial structure factors in binary mixtures in order to remove the coupling between concentration and density fluctuations artificially introduced bv Bhatia and Thornton when the components are of different size. Finally, the amplitudes of the concentration fluctuations near a critical point are discussed.
Symmetry Coordinates and Force Field Analysis of a Heptamolybdate, Mo7O24, Model
Authors: Lyhamn Lennart E. , Cyvin S. J.
Published: February 2015

A complete vibrational analysis is performed for a heptamolybdate, Mo7O24, niodel of C2V symmetry. The symmetry coordinates are classified into those of (a) framework vibrations, (b) ligand vibrations, (c) framework-ligand couplings, and (d) interligand vibrations. A simple valence force field is estimated, and a relative scale for the force constants of the angles is pre­sented. Vibrational frequencies are calculated and the influence of inclusion of redundancies is investigated. The final result is compared with experimental data from infrared and Raman. In the calculation of species A1 a correlation is found to all except one of the polarized Raman frequencies.
Notizen: On a Field-Theoretic Formulation of Scaling Laws in Molecular Scattering
Authors: Varracchio E. Ficocelli
Published: February 2015

Vibro-rotational excitation processes, in particle-diatom scattering, are considered from a field-theoretical point of view. It is shown that a relaxation of the relationship directly connecting boundary conditions and reference state, of the Green's functions of the theory’, can lead to a formulation of ab initio “scaling laws”, for both elastic and inelastic scattering.
Notizen: Measurement of the Hypersonic Velocity in the Molten Salts NaCl and KCl
Authors: Torell Lena M. , Knape H. E. Gunilla
Published: February 2015

The hypersonic velocity of molten sodium and potassium chlorides has been measured over a temperature range of about 100°C above the melting points. The measurements were carried out at scattering angles 90° and 140°, cor­responding to a 6-10 GHz frequency range. No deviation from previous ultrasonic values of velocity was observed at these frequencies, indicating that the measurements were performed at frequencies lower than any relaxation fre­quency.
Notizen: Zur Lumineszenz von aromatischen Verbindungen mit Schweratom-Substituenten in unterschiedlichen Bindungssituationen / On the Luminescence of Aromatic Compounds with Heavy Atom Substituents in Different Bonding Situations.
Authors: Blümer G.-P. , Zander M.
Published: February 2015

Compounds like III(4,9,10,11,12,13,13-Heptachloro-8b,9,12,12a-tetrahydro-9,12-methano-benzo[e]pyrene) are ex­amples for systems with heavy atom substituents in two different bonding situations. The halogen directly connected with the 7-electronic system causes an internal heavy atom effect whilst the halogens isolated from the .7-system by aliphatic carbons produce a “quasi external” heavy atom effect. The observation that the internal heavy atom effect in III is weaker than in halo phenanthrenes is explained with the lower electron density in the phenanthrene unit of III compared to phenanthrene. this lower electron density being a result of field and inductive effects of the peripherically arranged chlorine atoms.
Notizen: On the Structural Differences between Trifluoromethyl Sulphonyl Chloride (CF3SO2Cl) and Methane Sulphonyl Chloride (CH3SO2Cl)
Authors: Mayer István , Hargittai István
Published: February 2015

CXDO/2 MO calculations show the elektron withdra­wing ability of the CF3 group versus the electron releasing of the CH3 group to be the primary source of the consi­derable S-C bond lengthening in CF3SO2Cl as compared with CH3SO2Cl.
Raman-Spektroskopische Untersuchungen an PCl5. IV. Das System PCl5 —SnCl4 / Raman Spectra of the System PCl5 -SnCl4
Authors: Brockner W. , Demiray A. F.
Published: February 2015

Raman spectra of some solid and molten PCl5- -SnCl4- mixtures have been recorded. According to the stoichiometry SnCl5
- and additional SnCl6
2- complex ions are present in the solid state. The 1 : 1 melt is built up by PCl4
+ and SnCl5
- ions. PCl5 rich melts contain PCl5 molecules in addition, but almost no SnCl6
2-. SnCl4 rich melt mixtures are composed of PCl4
+ , SnCl5
- and SnCl4 .
Pair and Triplet Distribution Functions of Molten KCl from an MD-Simulation
Authors: Schäfer L. , Klemm A.
Published: February 2015

Pair and triplet distribution functions of the NaCl-type lattice and MD-simulated molten KCl are compared. Some similarities in the arrangement of the nearest neighbours are observed.
Interaction of the Quinoline Derivatives with Coenzyme Q10
Authors: Al-Khuzzaii Suhaila , Al-Rufaie Elham M. , Khalil Salim M. , Shanshal Muthana
Published: February 2015

The interaction of the quinoline derivatives with CoQ10 is studied both experimentally, using Polarographie and spectrophotometric techniques, and theoretically, applying the perturbation molecular orbital theory. The E1/2 potentials of a series of 1:1 solution mixtures of quinoline derivatives with CoQ10 are measured and compared with E1/2 of the coenzyme alone (0.52 V). An increase in the E1/2-magnitude of the coenzyme is detected (⊿E1/2 ≈ 0.03-0.13 V). Simple perturbation molecular orbital treatment shows an increase in the energy of the lowest unoccuppied molecular orbital of the coenzyme due to the same interaction, in agreement with the Polarographie results. The complexation constants of the same quinoline derivatives, as well as the antimalarials quinine, primaquine and chloroquine, with CoQ10 are determined spectrophotometrically and found to be in the order of 105 . The K value for each complex is determined at 10 different wavelengths and 7 different constituent concentrations of the solution. The complexation enthalpies are all small and positive (0.98-4.53 kcal/mol), the entropies are big and positive (29-41 cal/deg.mol). The big entropy change suggests an increase in the internal motion of the complexing molecules. It is suggested that the increase in the internal motion is due to the increase in the motion of the isoprenoid side chain of the coenzyme.
An Investigation of the Positive Column of a Hollow Cathode Arc in a Magnetic Field. Part I
Authors: Boeschoten F. , Komen R. , Sens A. F. C.
Published: February 2015

The positive column of the hollow cathode arc consists of a highly ionized ( > 90%) and -magnetized (ωei τi,i > 1) plasma. In order to obtain as much as possible information about this plasma its parameters were measured as functions of radius, r, and axial distance, z. They were varied by changing the discharge parameters - arc current I , gas feed Q, magnetic field strength B, arc length L and core diameter d. Generally the discharge was fed with Argon, but Neon, Helium, Nitrogen and Hydrogen were also used.

- The radial plasma density distribution, ne(r), is approximately Gaussian for 0 ≦ r < 4 cm (ne(0)≅ 2 X 1014 part./cm3); in axial direction the plasma density does not vary much.

-The ion temperature, Ti, is constant with radius, contrary to the electron temperature, Te, which drops sharply near the core of the arc. In axial direction Ti drops by a factor ten from the cathode to the anode (Ti ≅ 1- 30 eV). Ti (z = 0) increases with arc length L.

- The whole plasma moves in axial direction from the cathode towards the anode ( υz ≅ 6 X 104 cm/s); the angular mass velocity (Ω ≅ some 105 rad/s) is strongly sheared and decreases with temperature.

- The axial electrical field is small (0.1 to 0.2 V/cm) corresponding to a normal electrical conductivity. The radial electrical field points inwardly and varies strongly with radius (0 ≧ Er ≳ - 10 V/cm).

- Strong (nonlinear) low frequency oscillations (υ ≅ 15 kHz) are generated spontaneously in the plasma; these oscillations are due to the Kelvin-Helmholtz instability.

As is shown in Part II of this investigation, the observed behaviour of the plasma column may be satisfactorily explained by the two fluid model with MHD ordering. Due to viscous effects (i, i collisions) the sheared plasma rotation has big consequences for the transport of particles and energy.
Nuclear Magnetic Resonance in Solid Zinc
Authors: Herberg H. , Abart J. , Voitländer J.
Published: February 2015

The nuclear magnetic resonance of 67Zn in hexagonal close-packed Zn metal has been observed at 4.2 K by pulsed NMR with three different frequencies. The spin echo profile showed a well resolved powder pattern due to electric quadrupole interaction. The quadrupole coupling constant was determined to be e2 q Q/h = 12.0 (4) MHz. The spin-spin and spin-lattice-relaxation times were measured to be T2 = 58 ± 2 ms and T1 = 0.45 ± 0.2 s, respectively. The isotropic Knight shift is found to have the value Kiso = 0.1 ± 0.05%.
Evidence for Polymorphism within the So-called "Blue Phase" of Cholesteric Esters. IV. Temperature and Angular Dependence of Selective Reflection
Authors: Bergmann K. , Stegemeyer H.
Published: February 2015

From selective reflection (SR) measurements as a function of temperature it has been shown that cholesteryl myristate exhibits two "blue phases" (BP) between the isotropic and the cholesteric state. The SR of the two BP shows the same angular dependence as found in the cor-responding cholesteric state. From our results a model of the BP is proposed with the molecular axes inclined to the helix axis by a critical angle of 54.74° explaining the absence of birefringence as well as the cholesteric-like optical properties.
Dipole Moments, Polarizabilities and the Fluorescence Behaviour of 4-(9-anthryl)-N,N-dimethylaniline
Authors: Baumann Wolfram , Petzke F. , Loosen K.-D.
Published: February 2015

It is shown that the solvent dependence of the fluorescence wavenumber and decay time as well as the solvent dependent effect of an external electric field on the absorption and fluorescence spectra of 4-(9-anthryl)-N,N-dimethylaniline can be fully understood taking into account reaction field induced polarizability effects.
Infrared Spectra of Matrix Isolated Alkali Tetrafluoroaluminates, AlkAlF4 (g)
Authors: Huglen Reidar , Cyvin Sven J. , Øye Harald A.
Published: February 2015

The 1 : 1 adduct compounds which are the prevailing vapour species over equimolar mixtures of AlkF and AlF3 (Alk = Li, Na, K, Rb and Cs) in the temperature range 450-750°C have been isolated in argon and nitrogen matrices and examined bv infrared spectroscopy. Seven frequencies which are assigned to matrix isolated alkali tetrafluoroaluminate molecules have been found for all systems investigated. Group theoretical analysis and subsequent normal coordinate computations of the reassigned frequencies confirm a structural model for the AlkAlF4 molecules having the symmetry C2v-However, the results from this analysis cannot be taken as a definite confirmation of a true bidentate structure for these molecules in the vapour phase. The alkali metal-fluorine bond is found to be rather weak, and the Al-F terminal bond is found to be stronger than the Al-F bridge bond. Qualitative relations between matrix as well as vibrational shifts and potential energy distribution are discussed.
The Molecular Structure of 2-Methyloxacyclobutane, as Studied by Electron Diffraction
Authors: Schultz György , Bartók Mihály
Published: February 2015

A gas electron diffraction study of 2-methyloxacyclobutane has been carried out at room nozzle temperature. The four membered ring takes a planar conformation. The mean ra values for the O-C, C-C and C-H bonds are 1.448(5)A, 1.534(4)A and 1.118(3) Å, respectively. The endocyclic bond angles are C-C-C = 85.5(18)° and C-C-O=91.2 (15)°, while the angle C-O-C was assumed to be 92°. The position of exocyclic carbon atom was characterized, in addition by < Cexocyclic-C-O = 110.7(7)° and torsional angle Cexocyclic-C-O-C = 59.6(40)° (0° corresponds to the anti position of Cexocyclic-C and O-C bonds).
Lattice Animals as Limits of Clusters in Percolation Theory
Authors: Rocksloh B. , Stauffer D.
Published: February 2015

We investigate if the limits p → 0 or p → 1 for large percolation clusters at concentration p correspond to large lattice animals for fixed size s or fixed perimeter t, respectively. A numerical analysis for the asymptotic number of lattice animals with fixed large perimeter shows that the limit s → ∞ can be interchanged with the limit p → 0, but the two limits t → ∞ and p → 1 cannot be interchanged.
ESR-Relaxation von FeCl4
- -Komplexen in elektrisch polaren organischen Lösungsmitteln
Authors: Dietz W.
Published: February 2015

ESR-linewidths at X-band and Q-band frequencies of FeCl4
- in dilute organic solvents (ketones, nitriles, amides and aliphatic alcohols up to n-decanol) at room-temperature are reported. Correlation times and structural parameters of zero field splitting (ZFS) modulation are discussed with respect to the effective relaxation process. It can be shown that for the non-associating solvents the modulation of the ZFS is due to collisions with molecules tumbling in the solvent sheet. In alcoholic solution the rotating hydroxyl group of not associated molecules in the neighbourhood of the chlorine ligands must be assumed to determine the dynamics of the ZFS-modulation.