bluuebunny/crossref_metadata_2025 huggingface dataset:
Triplet State Properties of Binary Mixed Crystals of Dibenzofuran and Fluorene
Authors: Schweitzer D. , Zimmermann H.
Published: February 2015

Phosphorescence spectra and ODMR measurements at 1.3 K on a series of 13 mixed crystals of dibenzofuran (DBF) and fluorene (F) as well as of neat crystals of DBF and F (X-traps) are reported. Drastic changes in the spectra with different F:DBF ratios are observed, demonstrating the possibility of investigations of the electronic properties of F monomers, dimers, trimers and larger aggregates in this mixed crystal system of two chemically different molecules.
Elektrotransportversuche mit epitaktischen Goldschichten
Authors: Kleinn W. , Hübner H.
Published: February 2015

Electrotransport Experiments with Epitaxial Gold Films Electrotransport in gold films of 60 nm thickness grown epitaxially onto hot (100) NaCl substrate is determined from the growth rate of voids forming in the temperature gradient in short specimens observed in the transmission electron microscope while loaded with direct current densities of several 106 A/cm2 . For the temperature range 631 -1214 K an activation energy (1,19 ± 0,05) eV is found.
Variational Principle for Linear Relaxation Relations
Authors: Grossmann S.
Published: February 2015

A variational principle for linear relaxation phenomena is considered. I t connects relaxation with anti-relaxation. The latter one is governed by the transposed transport matrix and, in addition, by the diffusion matrix, which drops if Onsager-symmetry holds. This generalizes an earlier result by L. Waldmann
The Nature of Chaos in a Simple Dynamical System
Authors: Shibata Akira , Mayuyama Toshihiro , Mizutani Masahiro , Saitô Nobuhiko
Published: February 2015

A simple one-dimensional transformation xn = axn-1 + 2 - a (0 ≦ xn-1 ≦ 1 - 1 / a ) ,

xn = a( 1 - xn-1) (1 - 1 a ≦ xn-1 ≦ 1) (1 ≦ a ≦ 2) is investigated by introducing the probability distribution function Wn(x). Wn ( x ) converges when n → oo for a > V 2 , but oscillates for 1 < a ≦ V2. The final distribution of Wn(x) does not depend on the initial distributions for a > V2, but does for 1 < a ≦V2 Time-correlation functions are also calculated
Hyperfine Structure in the Rotational Spectrum of CuBr
Authors: Hoeft J. , Nair K. P. R.
Published: February 2015

The hyperfine structure of the J = 2 ← 1 rotational transition of CuBr has been measured in the 12 GHz frequency region using a Stark modulated high temperature microwave spectrometer. The molecules were produced by the reaction of Br2 vapour with copper in the heated zone of a splitted wave guide at a temperature of 800 °C. The analysis of the hyperfine structure yielded the following quadrupole coupling constants
On the Electronic Structure of Metal Hydrides I. Exposition of a Many-Electron Theory
Authors: Wahl F. , Baumann G.
Published: February 2015

We present the concept of a many-electron theory for the calculation of the energy difference between an undisturbed metallic host lattice and a crystal disturbed by stored hydrogen atoms. With the help of an elimination procedure a multidimensional system of equations is reduced to a one-particle Schrödinger equation for the electron of the hydrogen. The interaction with the electrons of the metal is then described by a dynamical potential depending on the state of the electron itself. A first order approximation with static screening is discussed and then generalized to a self-consistent calculation of one-electron functions which are used as a basis for expansions.
Mikrowellen-Spektrum und Struktur des Methyldichlorsilans / The Microwave Spectroscopy and the structures of Methyl-di-chloro-Silane
Authors: Kraft H.-G. , Haas B. , Zeil W.
Published: February 2015

By microwave spectroscopy (Stark-spectroscopy and microwave/microwave double resonance spectroscopy) we determined the structure of Methyl-di-chloro-silane. A partial rs-and complete r0-structure is given. The structure is in good agreement with some relationships concerning the structure of related molecules given by other authors.
Infrarotabsorption von reinem Dichlormethan bis zu hohen Drücken und Temperaturen / Infrared Absorption of Pure Dichloromethane Measured up to High Pressures and Temperatures
Authors: Buback M. , Franck E. U. , Lendlc H.
Published: February 2015

The infrared absorption of the ν1 and ν6 stretching fundamentals and of the ν2 CH2-bending mode in pure dichloromethane has been measured up to pressures and temperatures of 2 kbar and 200 °C, respectively. The optical high pressure cells were equipped with CaF2 single crystal windows. The applicability of this window material at high pressures and temperatures was investigated.

With increasing density the wavenumbers of maximum absorption of ν1 and ν2 shift to lower and of ν6 to higher values. The integrated molar absorptivity of ν2 and ν6 increases with in-creasing density while it remains nearly constant for the ν1 vibration.

The results obtained for the C-H modes clearly differ from those measured for O-H or N-H vibrations in polar materials. They are attributed to the action of repulsive forces in dense CH2Cl2.
Molecular Orbital Calculations on Penta Coordinated Ferric Dithiocarbamates Exhibiting Intermediate and Low Spin Ground States
Authors: Ganguli P. , Hasselbach K. M.
Published: February 2015

SCCEHMO calculations show that the ground state in [Fe(dtc)2X], X = Cl, Br, I and NCS, is 4A2: (x2 - y2)2(xz)1(yz)1(z2)1(xy)0 and for X = NO is 2A1: (xz)2(yz)2(x2-y2)2(z2)1(xy)0. The calculated quadrupole splittings of iron and iodine included the valence shell, overlap charge, and the ligand and lattice contributions to the EFG tensor at the nuclei. In addition, the elec-tron densities at the iron nucleus are compared with the measured isomer shifts. The spin densi-ties may be interpreted in terms of a π-delocalization. The results are discussed on the basis of the molecular orbital energy level schemes.
Binding Energies in Zr from (d, p) and (d, t) Reactions
Authors: Borello-Lewin T. , Dietzsch O.
Published: February 2015

Neutron separation energies in 91Zr, 92Zr, 93Zr and 95Zr were determined by measurements of relative Q-values for (d, p) reactions on Zr isotopes. A comparison is made with separation energies derived from a previous measurement of (d, t) reaction Q-values. The neutron separation energy in 95Zr disagrees by three standard deviations with the adjusted value in the 1977 Atomic Mass Evaluation.
On the Evaluation of the Specific Mass Shift in the Ground States of Members of the He Isoelectronic Series
Authors: Saha Subal , Sengupta Sankar
Published: February 2015

A variation-perturbation method to calculate the specific mass shift in the ground state configuration of members of the He isoelectronic series is proposed. Through minimization of the second order energy, completely coupled and correlated orbitals are obtained in the Hartree Fock approximation. The influence of the Pauli principle and the electrostatic interaction on the motion of the electrons are automatically included while estimating the specific mass shift. This procedure also enables expectation values of the operator r1 · r2 to be calculated easily.
Silicon Compounds in the Jupiter Atmosphere
Authors: Howland Glenn , Harteck Paul , Reeves Robert R.
Published: February 2015

Due to the relatively large cosmic abundance of Si and the stability of colored silicon compounds easily formed under various nonequilibrium conditions, it is concluded here that silicon should be strongly considered as a potential major component in the observed colored material in the Jupiter atmosphere. Silicon is one of the most abundant elements in the universe (after H, He, 0, N, and C) and in the same order of abundance as Mg and Fe. In the high temperature and pressure regions of Jupiter most of the Si should be present as SiH4. At higher altitudes, corresponding to a total pressure of less than 1000 bar and a temperature below 1200 K, SiC>2 and other compounds of silicon should dominate. These equilibria and the chemistry depend strongly upon the H9O concentration, which is assumed to be in the order of 10~ 3 . A calculated equilibrium profile had been proposed for a model atmosphere [1] and our own estimates confirm the main features within reasonable limits. Recent photographs taken of Jupiter emphasize the fact that the atmosphere of the planet is not in equilibrium. Atmospheric turbulence is observed corresponding to movement in the colored areas including the well-known great red spot. Assuming, therefore, that non-equilibrium processes may occur on Jupiter, the nature of such processes may be sought in the laboratory. The non-equilibrium transition of SiH4 to Si(>2 can be observed in various ways. We have found that many of these lead to intermediates that are relatively stable and yield strong colorations very similar in appearance to those observed on Jupiter. The purpose of this paper is to emphasize the possibility of the silicon compounds contributing
A Double Hard Sphere Model of Liquid Semi-Metals: Applications to Bismuth and Tin
Authors: Orton B. R.
Published: February 2015

The double hard sphere model previously used to calculate the interference functions for liquid Ge, Sb and Ga has now been applied to Sn and Bi. The main features of the observed interference functions just above the melting points have been reproduced, within experimental error, by the superposition of two different partial interference functions represented by hard sphere functions with packing densities of 0.475 and 0.470 for Sn and 0.430 and 0.400 for Bi and respective hard sphere diameters; 3.030 Å and 2.420 Å: 3.335 Å and 2.450 Å. The model has been developed to give a qualitative picture of the bonding in the liquid with the short distance associated with possible overlap of p orbitals. Further, this model has been shown to be in keeping with an alternative employing a ledge type interatomic potential by referring to the measured compressibilities.
Kontrollierbare Isotopenfraktionierung bei Massenspektrometern mit thermischer Ionisierung / Controllable Isotope Fractionation with Thermal Ionisation Mass-Spectrometers
Authors: Hebeda E. H.
Published: February 2015

Isotopic ratios measured with thermal ionisation mass-spectrometers are biased by fractionation effects. A sample must therefore be analyzed according to the same procedures as applied for the analysis of the standard reference material. A comparison of the behaviour of the sample with that of the standard can then be used as a criterion whether the analytical results are acceptable or not. In this way it is possible to obtain reproducibilities similar to those for elements where the fractionation can be determined by an internal standard. This procedure of controlled fractionation is demonstrated by means of the 88Sr/86Sr ratios measured on geological samples and the SRM 987 standard.
Noble Gases in Ten Stone Meteorites from Antarctica
Authors: Weber Hartwig W. , Schultz Ludolf
Published: February 2015

The concentrations and isotopic composition of noble gases have been determined in all ten stone meteorites recovered in Antarctica during 1976-1977 by a U.S.-Japanese expedition. From a comparison of spallogenic and radiogenic gas components it is concluded that the chondrites Mt. Baldr (a) and Mt. Baldr (b) belong to the same fall but that all other stone meteorites are individual finds.
Stability of Internal Modes in Circularly Cylindrical MDH Equilibria
Authors: Lortz D. , Nührenberg J.
Published: February 2015

The stability of internal modes, i.e. modes which leave the plasma boundary unperturbed, is discussed for magnetohydrostatic equilibria in circularly cylindrical symmetry. Stability analysis can be performed analytically by expansion near the magnetic axis. Marginal stability conditions relating the pressure gradient and the shear are determined.
Quantitative Analysis of Microsegregation in the Faceted and Non-Faceted Czochralski Silicon Crystal Growth
Authors: Kim K. M.
Published: February 2015

The microsegregation behaviour of antimony in the faceted and non-faceted Czochralski silicon crystal growth was analyzed quantitatively. Using small melt heights and no rotation, dopant striations of various small spacings were eliminated. Interface demarcation and spreading resistance measurements were used for the segregation analysis. The dopant concentration and its fluctuation during the faceted growth were both higher than during non-faceted growth. On the other hand, fluctuations of the microscopic growth rate were about the same in magnitude and periodicity in the two growth regions.
On the Thermal Behaviour of the n·C13-n·C20 Lithium Soaps
Authors: Franzosini P. , Sanesi M. , Cingolani A. , Ferloni P.
Published: February 2015

The phase transition temperatures and enthalpies were determined by differential scanning calorimetry between room temperature and the isotropic liquid region for the lithium n.alkanoates from tridecanoate to eicosanoate. The number and nature of the phases involved were discussed in comparison with the literature data available for some of the homologues concerned. For diffe-rent kinds of transitions, the significant features of the plots AS vs. number of carbon atoms were put into evidence.
Raman-spektroskopische Untersuchungen an PCl5 V. Das System PCl5-HgCl2
Authors: Fezâ A. , Brockner Wolfgang
Published: February 2015

Raman spectra of some solid and molten PCl5-HgCl2 mixtures (formation of 2 phases) have been recorded. In the system investigated the compounds (PCl4)2 HgCl4 and (PCl4)n (HgCl3)n were found. The structure of (PCl4)n (HgCl3)n is polymeric likely as that of NH4 HgCl3. In this case melting causes a fragmentation into smaller but still polynuclear units of varying chain length. The temperature dependency of the solubility of PCl5 in the lower phase influences the existing equilibria.
1,2,4-Triazole Complexes VIII *
Authors: Engelfriet D. W. , Groeneveld W. L. , Groenendijk H. A. , Smit J. J. , Nap G. M.
Published: February 2015

Co(trz)2(NCS)2 has been investigated by means of magnetic susceptibility and magnetization measurements on single crystals in the temperature range from 1.1 - 300 K, heat capacity measure­ments from 1.5 - 90 K, neutron powder diffraction at 1.2 K and ESR measurements on the Co­doped Zn compound at 9 K. The compound appears to have two-dimensional structural and mag­netic properties. A transition to an antiferromagnetically ordered state takes place at Tc = 5.71 (1) K. Susceptibility measurements along the three orthorhombic axes reveal a strongly anisotropic character. The b axis is found to be the preferred axis of antiferromagnetic alignment. The susceptibility data along b and the heat capacity results are in good agreement with the predictions for the quadratic layer, S=½, XY antiferromagnetic, with an intralayer exchange constant j/k= -5.0(1)K. Below Tc the field dependent behaviour of the magnetization and the susceptibility along the a axis exhibits a transition at ~ 1 kOe. Hidden canting is found to be present. The magnetic structure can be described by four sublattices with the magnetic moments lying in the a-b plane along directions that are at an angle of 7° with the b axis.
Konformation konjugierter Cyclopropanderivate mit sterischer Hinderung / The Confirmation of Cyclopropane Derivatives with a Rotation Barrier
Authors: Al-Nia'mi Rajiha I. , Shanshal Muthana
Published: February 2015

The influence of α- and o-methyl substituents on the conformation of phenylcyclopropane is studied. Synthesis as well as low temperature PMR studies of the corresponding derivatives are carried out. The changes in the PMR spectra measured at room temperature and -100 °C are too small to count for the rotation barrier calculations. Fo 2,2-dichloro-1-phenyl-cyclopropane (8) ,2,2-dichloro-1-methyl-1-phenyl-cyclopropane (9) and 2,2-dichloro-1-o-tolyl-cyclopropane(10) the predicted most stable conformation is the near-bisected in which the aromatic ring is slightly twisted towards the CI atoms. For 2,2-dichloro-1-(2,6-dimethyl-phenyl)-cyclopropane (11) the planar conformation is predicted to be most stable. MINDO/3-FORCES calculations of the conformations and rotation barriers of similarly methylsubstituted vinyl-cyclopropanes, phenylcyclopropane and 2-cyclopropyl-pyridine are reported. It is found that introducing a methyl group to the a-position of the three membered ring or to the C4 atom f the vinylgroup causes the deviation of the olefine plane from the bisected conformation by 30°. Similar deviations are expected for the α-and o-methyl-phenylcyclopropanes.
Quarks im Lichte einer Idee von Pais
Authors: Bopp Fritz
Published: February 2015

A wave equation of a kind proposed by Pais in 1953 describes a particle with an infinite sequence of quantum states, which belong to the symmetrical representations (λ, 0) of the group SU 3. Particles composed of such single ones are connected with the whole set of representations (λ, μ) of SU 3. The wave equation is compatible with an exclusion principle. Assuming that only particles with zero triality occur, all quarks and quarklike particles are excluded. Neither coulours, nor bags are needed, as we do not need repulsive forces to exclude Li-atoms with symmetrical wave functions.
Emission Spectra of Crystal Phosphor BaCl2-Pb
Authors: Tabakova Veneta , Kynev Kyncho
Published: February 2015

Emission spectra of Pb2+ centres in barium chloride single crystals have been studied between 4 and 300 K by excitation with different wave lengths. Excitation spectra at 300 K have also been obtained by measuring the emission in the maxima of the shoitwave and longwave bands. The results allow to conclude that the high energy emission band is due to the transition | 3T1u > → | 1A1g > in the activator ion. The more effective excitation of the low energy emission band observed in the shortwave region of the absorption spectrum and the complex nature of both bands are discussed.
Routes to the Formation of Association Products in CO2 from Reactions of CO2 · CO2
+ Ions with Several Neutral Molecules
Authors: Rakshit A. B. , Warneck P.
Published: February 2015

The reactions of CO2·CO2
+ ions with SO2 , O2, C2H2, COS, NH3, and CS2 have been re-investigated to determine the yields of products of the type CO2·A+ , where A is the neutral reactant molecule. The same products are also formed by third body attachment of A2
+ to CO2 . In addition, A2
+ cluster ions are observed in several cases. Rate coefficients for these reactions are given.
On the X-ray Scattering Factor of Metallic Lithium in the Long-Wavelength Limit: The "Solid State Effect"
Authors: Visser E. G. , Geertsma W. , Lugt W. van der , Hosson J. Th. M. de
Published: February 2015

By considering three successive approximations to the conduction-electron wavefunction of metallic lithium, it is shown that the X-ray scattering factor at small wavevectors is very sensitive to the model chosen for describing the electron density. It is demonstrated that, when screened pseudopotentials are used, the "solid state effect" is almost negligible in this region of wave-vectors.
Haloalkane-Aromatic Complexes in the Ground and Excited States Molecular Orbital Calculation
Authors: Brinn I. M.
Published: February 2015

CNDO/2 calculations have been carried out on a series of haloalkane-aromatic 1: 1 complexes in the ground and first excited singlet states and one 2 : 1 complex in the ground state. Calculated stabilities agree very well with reported experimental results for the ground state. Our calculations indicate that the substituent effect on complex stability in excited states will be the opposite of that found for the ground state.
Versuche zur Berechnung der Fluoreszenzspektren organischer Farbstoffe
Authors: Fabian Walter
Published: February 2015

Attempts to Calculate the Fluorescence Spectra of Organic dyes Within the scope of the PPP-approximation a β-variation procedure is used to calculate the fluorescence spectra of some organic dyes and to estimate geometry changes upon excitation into the fluorescent state.
Note on a Topological Property of the HOMO-LUMO Separation
Authors: Gutman Ivan
Published: February 2015

The effect of cycles on the HOMO-LUMO separation of alternant conjugated hydrocarbons is examined. A general topological regularity is established, namely that (4m + 2)- membered conjugated circuits increase and (4w)-membered conjugated circuits decrease the HOMO-LUMO separation. Möbius cyclcs exhibit an opposite effect.
Magnetic Field Instability of a Plasma in a Beam of Electromagnetic Radiation
Authors: Gradov O. M. , Stenflo L.
Published: February 2015

A beam of electromagnetic radiation can generate magnetic fields in plasmas. It is shown that those fields grow significantly when the incident radiation is sufficiently strong. We obtain expressions for the characteristic time of the growth of the fields as well as for their spatial distribution and point out a possible mechanism, which can lead to the formation of a quasi-stationary state. The maximum value of the magnetic field strength is estimated
The Millimeter Wave Rotational Spectra of Carbonyl Sulfide
Authors: Dubrulle A. , Demaison J. , Burie J. , Boucher D.
Published: February 2015

The following rotational spectra of carbonyl sulfide have been accurately remeasured with a beam-absorption spectrometer:

16O12C32S in the vibrational ground state and in the vibrational state 0 11 0.

16O12C34S in the vibrational ground state.

The ground state spectra of the following isotopic species have been measured with a video spectrometer:

17O12C32S, 18O12C32S, 16O13C32S, 16O12C33S, 16O12C36S, and 16O13C34S.

Our measurements have enabled us to improve the molecular constants notably for these cases.
On Maximizing the Information from an Indirect Experiment
Authors: Hofacker G. L. , Levine R. D.
Published: February 2015

The information about an observable A provided by an indirect experiment in which observable B is measured is used as a criterion for comparing the performance of different observables B and for selecting an optimal initial state.
Network Structure of a System coded by Groups
Authors: Busse H. G. , Havsteen B. H.
Published: February 2015

A system may be characterized by its dynamics as well as by its structure. Several kinds of schematic drawings have been proposed to represent the structure of a system. Here, the representation of the structure by free groups is discussed. Free groups are an abstract mathematical tool, which permits the systematic treatment of a structure. The suggestion is exemplified by its application to a chemical kinetic model. The structure of the model is given (coded) by a linear sequence of symbols. The interaction of the environment with the structure (mutation) and the relation between structure and systemic boundaries (finiteness) are treated. The concept probably also applies to biological systems. Also, context-free languages could be used as alternate representations of system structures.
Molecular Rydberg Transitions. X Correlation Algorithms for Rydberg Term Values
Authors: Hochmann P. , Findley G. L. , McGlynn S. P.
Published: February 2015

The empirical linear correlations of Rydberg term values [S. P. McGlynn, S. Chattopadhyay, P. Hochmann, and H.-t. Wang**, are discussed in a first-order perturbation-theoretic format. In the second-order, quadratic dependencies are expected. The theoretical development assumes that the gross features of interatomic and intermolecular Rydberg term value variations can be discerned using a one-electron model; that a molecule XS, X being the Rydberg chromophore and S the substituent, can be partitioned so that the affairs of the optical electron are dominated by its interactions with the chromophoric segment; and that the charge distributions, whether of X or S, can be expanded in ways which permit evaluation of the effects of small variations in either X or S on Rydberg term values. The development is restricted to Class 1 molecules: Molecules which possess a common S and variable X, but where all X must be of similar electronic structure e.g., X = F, Cl, Br, I). A variety of correlative algorithms is discussed, and the intergroup transferability of parameters is elaborated in terms of the properties of "average chromophores"
The Influence of Grain Boundary Migration on the Diffusion Behaviour of Thin Films
Authors: Ehrmann-Falkenau E. , Wagendristel A.
Published: February 2015

Simultaneous grain boundary-, surface- and lattice diffusion in hypothetical thin film couples of miscible components was computer simulated. On this basis the diffusion into fixed and moving grain boundaries is discussed with respect to the determination of diffusivities by depth profiling methods. The data evaluated from the synthesised depth profiles according to Whipple-Le Claire as well as to Gilmer and Farrell were compared with the diffusivities used for the computation. Agreement was found for systems with a fixed grain boundary network. Moving grain boundaries, however, may cause errors of an order of magnitude towards lower grain boundary diffusivities
On the Determination of the Cholesteric Screw Sense by the Grandjean-Cano-Method
Authors: Gerber Paul R.
Published: February 2015

A theoretical treatment is presented for the determination of the screw sense of a cholesteric substance in a Grandjean-Cano-wedge by observing the sample in a polarizing microscope. For comparison some experimental measurements are given
X ɑ Method with Pseudopotentials
Authors: Szasz Levente
Published: February 2015

The l a method for an atom or molecule is transformed into an all-electron pseudopotential formalism. The equations of the X ɑ method are exactly transformed into pseudo-orbital equations and the resulting pseudopotentials are replaced by simple density-dependent potentials derived from Thomas-Fermi model. It is shown that the new formalism satisfies the virial theorem. As the first application it is shown that the model explains the shell-structure of atoms by the property that the pseudo-orbitals for the (ns), (np), (nd) etc. electrons are, in a very good approximation, the solutions of the same equation and have their maxima at the same point thereby creating the peaks in the radial density characterizing the shell structure
Magnetic and Electrical Transport Properties of Vanadium Telluride
Authors: Prasad C. , Singh R. A.
Published: February 2015

Measurements of the magnetic susceptibility of a powdered sample of VTe in the temperature range 90 - 700 K, and of the a.c. electrical conductivity (σ), thermoelectric power (θ) and dielectric constant (ε′) of pressed pellets of the compound in the temperature range 300 -1100 K are reported. The compound is found to be antiferromagnetic with Neel temperature 420 ± 5 K. The effective paramagnetic moment and paramagnetic Curie temperature are found to be 1.6 μB and - 250 K, respectively. The dependence of σ, θ and ε′ on temperature shows no anomaly at the Neel temperature and is indicative of the metallic nature of the compound.
Der Lumineszenzprozeß in kristallinem Dibenzofuran mit Fremd- molekülen kontrollierter und unkontrollierter Konzentration (I. Die prompte Fluoreszenz)
Authors: Hoffmann Klaus-Dieter
Published: February 2015

The prompte fluorescence of pure and anthracene doped crystals of dibenzofuran is characterized by the participation of a trap-fluorescence as can be concluded from the spectra and the fluorescence decay. The molar fraction of the traps has been estimated to be about 10-3 . A model is presented to describe the observed temperatur dependence of the fluorescence in the range 4.2 ≦ T ≦ 293 K.
The Rotational Zeeman Effect of Thiazole and Isothiazole
Authors: Wiese Jürgen , Sutter Dieter H.
Published: February 2015

The rotational Zeeman effect of low J rotational transitions (J ≦ 3) has been investigated for Thiazole and Isothiazole. The measured susceptibilities are compared to those calculated within the model of localized (atomic) susceptibilities, and nonlocal contributions to the susceptibility component perpendicular to the ring are obtained. These nonlocal susceptibilities, if compared to those of a set of related compounds appear to correlate to the “aromatic character” as determined by chemical reactivity. Five or six membered rings with Χ⊥nonlocal < - 30 · 10-6 erg/G2 mol show “aromatic reactions” while molecules with -20 · 10-6 erg/G2 < Χ⊥nonlocal show “olefinic reactions”.
Microwavc Spectra of 3-Cyanotliiophene-34S and 3-Cyanothiophenc-15N and Partial r0-restructure
Authors: Wiese J. , Schwarz R. , Sutter D. H.
Published: February 2015

The rotational spectra of 3-Cyanothiophene-15N and 3- Cyanothiophene-34S were analyzed in the frequency range between 10 and 25 GHz.

A partial r0-restructure was fitted to the observed rotational constants. The cavity-Fourier-transform microwave spectrometer with pulsed supersonic nozzle beam gas injection is proposed as a promising tool to investigate the rotational spectra of vibrationally excited moleculs (ν̄vib ⪞ 800 cm-1).
Einfiuss der Donator-Akzeptor-Wechselwirkung bei Stilbenen auf die Polarität im ersten angeregten Singulettzustand
Authors: Gryczyński I. , Gloyna D. , Kawski A.
Published: February 2015

The electric dipole moments of some substituted stilbenes in the ground (μg) and the first excited singlet state (μe) have been determined and discussed in regard of the donor-acceptor- interactions. A linear correlation between the Hammett σp-constants and the values of μg, μe and Δμ = μe - μg for different substituted stilbenes was found.
Investigation of Rotational Relaxation by Double Resonance and Stark Switch Techniques
Authors: Schrepp W. , Dreizler H. , Guarnieri A.
Published: February 2015

For the four rotational levels JK₋K₊ = 101, 110,212 and 221 of ethylene oxide all possible four level double resonance experiments for dipole allowed transitions have been performed to investigate collisional effects and to determine the relative change of signal intensity, η = ⊿I/I, due to high power pump radiation. The T1 and T2-relaxation times have been measured for all dipole allowed transitions within these four levels.

A combination of the data obtained from both experimental methods allows the determination of rate and bath constants taking into account only first order dipolar transitions. No further restrictions have been used. This approximation is supported by a triple resonance experiment.

In addition to the pure gas investigation in the absence of external fields, rotational relaxation has been studied in the presence of a static electric field and in a mixture with hydrogen.
Alkali-Halide Chemiluminescence: Studies on the Fluctuation Bands from some Alkali (Li, Na, K)-Halogen (CI, Br, I)-Reactions
Authors: Roeder M.
Published: February 2015

Molecular chemiluminescence spectra from selected alkali-halogen reactions are presented using a beam-gas arrangement operating with pressures between 10-1 mtorr (single collision conditions) up to 10 mtorr in the reaction zone. Spectra are presented for the chemiluminescent reactions M2 + X2->MX* + MX, where M2 = K2, Na2 and X2 = Cl2, Br2, I2. The MX* emitter is identified by comparison with previous absorption and emission studies of these molecules. The sodium reaction with I2 as well as all lithium reactions with different halogens (Cl2, Br2, I2) do not yield appreciable molecular emission. The differences in molecular chemiluminescence intensities among this type of reactions can be understood in terms of the Landau-Zener formalism for an electron jump and turn out to be consistent with the results from measurements on absorption, emission and dissociation.
Notizen: A Note on the Off-Diagonal Elements of the Density Matrix in Thermal Equilibrium and Thermal Radiation
Authors: Sutter D. H.
Published: February 2015

A closer look at the off-diagonal elements of the density matrix of a thermal gas phase molecular ensemble reveals, that they lead to a contribution to thermal radiation which increases in power proportional to the number of particles. A quantitative comparison of this contribution to the one originating from spontaneous emission is given.
Elementare Herleitung der Dirac-Gleichung. IV
Authors: Sallhofer Hans
Published: February 2015

Elementary Derivation of the Dirac Equation. IV This paper attempts to make evident the basic ideas behind the alternative electrodynamic model of the hy-drogen atom.
Phonon Dispersion in Noble Metals
Authors: Agarwal R. M. , Rathore R. P. S.
Published: February 2015

A new lattice dynamical model comprising various interactions among the constituents of noble metals is developed. The model assumes central core-core coupling extending to the first neighbours only. Overlap interactions among neighbouring d-shells are expressed in terms of an angular parameter. Volume interactions for core-conduction electrons and d-shell-conduction electrons are described through a simple expression. Interactions between core and d-shell are also accounted for adequately.

The lattice is considered in equilibrium under the volume dependent energy of cores, conduction electrons and the d-shell electrons. The obtained dispersion relations for copper and silver are compared with (a) experimental data, (b) results of a recent first-principle calculation and (c) results of a recent phenomenological study.
Structure Analysis of Vacuum-Deposited Mg Thin Films
Authors: Haider N. C.
Published: February 2015

Thin films of Mg, in the thickness range of 23,000 ~ 93,000 Å, were prepared at 10-6 Torr pressure and 45° C temperature. The x-ray diffraction spectra (XDS) have been measured for several reflections with crystal monochromated and Ni-filtered CuKα1 radiation. A detailed Fourier analysis of the broadening of x-ray lines indicated very strong effects of the oxidation of the surface, thermal stress along 100 and 002 planes, and preferred orientation along 002 planes parallel to the surface of the substrate.
Annihilation of Positrons in Rare Gases — A Phenomenological Study
Authors: Grover P. S.
Published: February 2015

The life time, λ, of positrons in rare gases under the simultaneous influence of a steady magnetic and an alternating electric field is studied. λ depends on the frequency and attains a maximum when the frequency equals the cyclotron frequency. The extent of this dependence is quite sensitive to the positron atom momentum transfer rates.
Dynamische ESR-Untersuchungen zur Propellerform der Triphenylmethylgruppe
Authors: Scheffler K. , Digel F. , Krieg R. , Stegmann H. B.
Published: February 2015

The ESR spectra of substituted 4-oxyl-3,5-di-tert.butyl-benzyl-triphenylmethyl radicals ex-hibit the expected temperature dependence of the methylene protons, which is explained by internal hindered rotation of the phenoxyl ring. Furthermore, alternating linewidths have been observed. This phenomenon can be assigned to a two jump process between right-and left-handed propeller shapes of the triphenylmethyl substituents. The activation enthalpies depend on the sense of rotation of the phenyl groups and are found to be around 14.3 and 32.6 kJ/mol. Obviously the propeller shaped form of the triphenylmethyl group is due to steric reasons.
Cross Sections for Depolarization of 62P3/2 Cesium Atoms Induced in Collision with Noble Gases from D2 Optical Pumping
Authors: Rudedcki P.
Published: February 2015

Possibilities of examing the relaxation of alkali atoms in 62P3/2 state by analysing the pumping process with a weak circularly polarized D2 line are presented. Results of an experiment on Cs-He and Cs-Ne systems have also been given. Assuming the J-randomization model for relaxation of alkali atoms in 2P3/2 state and neglecting energy transfer between 62PJ states, we obtained the cross sections for relaxation: Cs-He, 62.6 ± 10.0; Cs-Ne, 54.0 ± 9.0; in 10-16 cm2 units.
Enthalpy of Formation of Gallium-Germanium-Tin Liquid Alloys: Evaluation of the Liquidus Surface of the Phase Diagram from Excess Functions of Mixing
Authors: Fornaris M. , Muggianu Y. M. , Gambino M. , Bros J. P.
Published: February 2015

With a differential high temperature Calvet calorimeter, the enthalpies of formation of Ga-Ge-Sn liquid alloys have been measured at 703, 798, 895, 1000 and 1230 K in the whole concentration area. The experimental results are compared with those obtained by using an interpolation relation on the basis of the excess functions of mixing of the bordering binary systems. The interpolation relation is used to calculate the partial excess functions and to determine the position of the liquidus surface of the Ga-Ge-Sn phase diagram: the experimental and calculated values agree fairly.
The Effect of Particles on Blast Waves in a Dusty Gas
Authors: Higashino Fumio , Suzuki Tateyuki
Published: February 2015

The effect of suspended particles on cylindrical blast waves is investigated by making use of a series expansion method with respect to 1/M2 take off [2], where M is the shock Mach number. Velocity and temperature equilibrium between the gas and the particles is assumed. As a result, one finds that the particles are assembled near the shock front and that behind it the slopes of the pressure and velocity profiles increase, as the volume fraction of particles increases. The difference between the zeroth and first order solutions becomes the smaller, the larger the volume fraction of the particles. The decay rate of a blast wave in a dusty gas is greater than in a dust-free gas.
Ne Emissions from a He Discharge Flow System: I. Relative Transition Probabilities of Ne
Authors: Haak H. K. , Zetzsch C. , Stuhl F.
Published: February 2015

A windowless microwave discharge in He was used to generate Ne emissions in a flow system. Relative transition probabilities for a number of emission arrays were determined from the observed line intensities. Agreement is generally obtained with previous experimental and theoretical work.
Population Analysis with Hydrogen 2 p Polarization Functions Included in the INDO Basis Set
Authors: Facelli J. C. , Contreras R. H.
Published: February 2015

Mulliken population analysis with 2p polarization functions included in the AO basis set of the INDO method has been performed for a set of molecules containing hydrogen as well as first row atoms. It is found that this enlargement of the basis set yields an increasing electron population in hydrogen atoms, in agreement with trends found in “ab initio” methods.
X-Ray Diffraction Study of a Concentrated Al(NO3 )3 Solution
Authors: Caminiti R. , Radnai T.
Published: February 2015

The scattering of X-rays from a concentrated Al (NO3)3 aqueous solution has been measured and analyzed at 25 °C. Good agreement with experimental data is achieved through a model in which Al3+(H2O)6 interacts with twelve water molecules through short and linear H-bonds. The water molecules which are the nearest neighbors to the Al3+ ions have trigonal orientation and each 0 atom in the nitrate ion gives rise to about 2 weak hydrogen bonds with water molecules.
Untersuchungen zur Anwendbarkeit semiempirischer SCF-Verfahren zur Behandlung von Tautomerieproblemen heterocyclischer Verbindungen/ Investigations on the Applicability of Semiempirical SCF-methods for the Treatment of Heterocyclic Tautomerism
Authors: Fabian Walter
Published: February 2015

Using hydroxy substituted 1,5-naphthyridines as examples various semiempirical SCF methods are tested for their applicability in heterocyclic tautomerism. It is shown that even in cases where the MINDO/3 method yields only insignificant results it is possible to get information upon tautomeric equilibria by a comparison of experimental UV spectra and excitation energies as calculated by the CNDO/S-CI method.
Notizen: Strömung von nematischen Flüssigkristallen in Kapillaren mit rechteckigem Querschnitt /The Flow of an Nematic Liquid Crystal in a Capillary with a Rectangular Cross Section
Authors: Schneider F.
Published: February 2015

The velocity profile for the flow of an incompressible nematic liquid crystal in a capillary with a rectangular cross section is calculated. Equations for the determination of the different viscosity coefficients from the volume flow rate and the pressure difference are presented.
Cation and Anion Reorientation at Phase Transition in Pyridinium Tetrafluoroborate
Authors: Wąsicki J. , Pająk Z. , Kozak A.
Published: February 2015

Temperature dependences of 1H and 19F second moment and spin-lattice relaxation times for polycrystalline pyridinium tetrafluoroborate were measured. A phase transition was discovered at 202 K. A model of cation reorientation between inequivalent (low-temperature phase) and equivalent (high-temperature phase) equilibrium positions is proposed. Whether the anion reorients isotropically or about a symmetry axis cannot be decided. An analysis of cross-relaxation effects yielded activation parameters for cation and anion reorientation. The rotational correlation times for both ions converge just at the phase transition reaching the value of 10-10s.
Calculation of the Resistive Ballooning Mode Growth Rate for a Class of 3-D MHD Equilibria
Authors: Correa-Restrepo D.
Published: February 2015

A previous derivation of formulae for calculating the growth rate of resistive ballooning modes which are described by a simple model equation is extended here to a large class of general tokamak and stellarator equilibria
Electrostatic and Packing Contributions to the Structure of Water and Aqueous Electrolyte Solutions
Authors: Holovko M. F. , Kalyuzhny Yu. V. , Heinzinger K.
Published: February 2015

The role of electrostatic and packing contributions to the structure of water and aqueous electrolyte solutions has been investigated by the comparison of results of Molecular Dynamics simulations with those of analytical calculations for the corresponding Lennard-Jones systems. It is demonstrated that the electrostatic interactions play a dominant role in determining the characteristic data of the various radial distribution functions in the solutions, although their relative importance decreases with increasing pressure, temperature, and ionic concentration. It is proposed that for the analytical treatment of hydrogen bonded liquids the total potential should be subdivided into three regions - short range repulsion, potential minimum, long range electrostatic interactions - and a different theoretical approach should be employed for each region
A Microwave Fourier Transform Spectrometer with a Single Microwave Source
Authors: Krüger M. , Dreizler H.
Published: February 2015

Design and performance of a microwave Fourier transform spectrometer in the frequency region around 8 GHz are reported. Operation and experimental set-up are simplified compared to previous designs.
Spontaneously Twisted Nonchiral Nematic Liquid Crystals
Authors: Chrzanowska A.
Published: February 2015

Nematic liquid crystals exhibiting a negative K2 elastic constant are discussed on the basis of a microscopic model potential. Stability conditions are satisfied by taking into account higher order terms in the expansion of the free energy. A continuous Freederiks effect is predicted for systems with negative K2.
Ionization of Liquid Tetramethyl Germanium by 60Co-γ-Radiation
Authors: Lopes I. , Schmidt W. F.
Published: February 2015

The ionization current produced in liquid tetramethyl germanium by 60Co-γ-radiation was measured with a guard ring type, parallel plate ionization chamber. The yield of ion pairs as a function of the applied electric field strength was determined and the free ion yield without applied electric field was obtained to be Gfi (0) = 0.68 ±0.10.
First Evidence of Self-Organized Criticality in the Impact Ionization Breakdown of Semiconductors
Authors: Clauss W. , Kittel A. , Rau U. , Parisi J. , Peinke J.
Published: February 2015

We have investigated the dynamical behavior of p-Ge at the very onset of impact ionization breakdown. The statistical temporal distribution of the recurrent breakdown events exhibits a power law behavior supporting the model of selforganized criticality introduced by Bak, Tang, and Wiesenfeld.
On the Electric Field Induced Stripe Instability Threshold of Twisted Nematic Layers
Authors: Nehring J. , Scheffer T. J.
Published: February 2015

Based on continuum theory, general expressions are derived which indicate how the electric field induced stripe instability threshold of twisted nematic layers is influenced by the liquid crystal material parameters. Results are applied to supertwist displays
Excited States Dipole Moments and Fluorescence Behaviour of Some Derivatives of Dimethylaminobenzonitrile
Authors: Brittinger C. , Maiti A. K. , Baumann W. , Detzer N.
Published: February 2015

Two sterically hindered derivatives of dimethylaminobenzonitrile (DMCA) have been synthesized and the dipole moment of their fluorescent excited state has been determined in differently polar solvents. Its value increases with solvent polarity up to a limiting value of (50 + 2.5) • 10-30 Cm. The results are discussed with reference to the twisted intramolecular charge transfer (TICT) state formation in the class of molecules related to DMCA.
A Reanalysis of 14N Nuclear Quadrupole Coupling and Methyl Internal Rotation in the Rotational Spectra of Monomethyl Oxazoles and Isoxazoles
Authors: Fliege Eckhard R. L.
Published: February 2015

Previously published rotational frequencies of 2-, 4-, and 5-methyl oxazole and of 3- and 5-methyl isoxazole are reanalysed to obtain correct rotational constants (A constants in the first place) on the basis of hypothetically unsplit rotational centre frequencies. With these, r0-structural parameters of the respective methyl group could be determined, thus allowing us to consider the influence of methyl substitution on the 14N-quadrupole coupling tensor and the structural relevance of the internal rotor angle given by torsional analysis.

14N nuclear quadrupole hfs and IAM methyl torsional analyses were redone with the correct rotational constants.
Notizen: Inviscid Burgers Equation, Painleve Analysis and a Bäcklund Transformation
Authors: Steeb W.-H. , Euler N.
Published: February 2015

The inviscid Burgers equation is studied with the Painleve analysis. A Bäcklund transformation is constructed. Then we give the symmetry generators. A two-dimensional case is also investigated.
The Quantum Statistical Free Energy Minimum Principle for Multi-Lattice Mean Field Theories
Authors: Gerisch Th. , Rieckers A.
Published: February 2015

The quantum statistical frame for infinite multi-lattice spin systems is introduced. The thermodynamic functionals specific internal energy, entropy and free energy are shown to exist on the set of permutation invariant states for polynomial mean field interactions by direct estimation methods. Their dependence on the relative sizes of the sublattice systems is made explicit. The set of homogeneous minimal free energy states is shown to be a Bauer simplex which contains all limiting Gibbs states. For the extremal minimal free energy states the self-consistency equations are derived.
Improved Molecular Constants of Acetylene Obtained from the v5 Band System
Authors: Moravec A. , Winnewisser G. , Yamada K. M. T. , Blom C. E.
Published: February 2015

A vibration-rotation band system of acetylene of the /Πu bending vibration v5 has been recorded with high resolution by a Bruker IFS 120 HR Michelson spectrometer. From the analysis of the hot band of the normal isotopic species, v4 + v5 - v4, and the fundamental band of HC13CH in natural abundance an improved set of constants has been derived. The intensity perturbation due to the l-type resonance has been clearly observed in the band system v4 + v5 -v4
A Theory of Anharmonic Perturbations in a Penning Trap
Authors: Kretzschmar Martin
Published: February 2015

Classical hamiltonian perturbation theory formulated in terms of action-angle variables is applied to develop a general and systematic method for calculating the influence of anharmonic perturbations on the motion of a charged particle in a Penning trap. Action-angle variables are ideally suited to determine the shifts of the characteristic frequencies in a perturbed orbit. The application of the method is demonstrated by several case studies