bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electronic Structure and Photophysical Characteristics of Substituted 3-(2-Benzthiazolyl)-Coumarins and Coumarinimines
Authors: Nikolova P. , Tyutyulkova N. , Dryanska V. 
Published: February 2015

The spectral properties of a group of 3-(2-benzthiazolyl)-coumarins and coumarinimines, some of them having high fluorescence quantum yield (Qf > 0.7), are described.
The quantum -chemical investigations show that the main chromophore of this group of dyes is the 3 -(2-thiazolyl)-2 H -pyran -2-one fragment

i.e . the coumarin (coumarinimine) and the benzthiazolyl fragments are not separate chromophores.
The Doubly Determined Substitution Structure of 1,2-Difluorobenzene
Authors: Stiefvater Otto L. 
Published: February 2015

Abstract
The carbon -fluorine bond length and the distortion of the benzene ring under fluorination have been determined by the isotopic substitution method for 1,2-difluorobenzene. -The experimental work was carried out predominantly by Double Resonance Modulation (DRM) microwave spectroscopy, which allowed the spectra of all 13C-forms to be studied in their natural abundance. The normal and the 4,5-d2 species were used as parent molecules, and the two sets of structure results are found to agree well with each other. With square brackets indicating consistency limits between the two sets of results, the following bond distances (in Å) and angles (in degrees) have been obtained:
C(1/2) - F(1/2) = 1.3494[4] ≮ C(1) C(2) F(2) = 119.16[1]
C(1) - C(2) = 1.3755[3] ≮ C(1) C(2) C(3) = 121.17[2]
C(2/1) -C(3/6) = 1.3786 [3] ≮ C(2) C(3) C(4) = 118.59 [2]
C(3/6) - C(4/5) = 1.4004 [3] ≮ C(3) C(4) C(5) = 120.24 [1]
C(4) - C(5) = 1.3917 [6] ≮ C(2) C(3) H(3) = 119.58 [1]
C(3/6) -H(3/6) = 1.0829 [1] ≮ C(3) C(4) H(4) = 119.55 [1]
C(4/5) - H(4/5) = 1.0813 [4]
The Doubly Determined Substitution Structure of 1,3-Difluorobenzene
Authors: Stiefvater Otto L. 
Published: February 2015

Abstract
The carbon -fluorine bond length and the distortion of the benzene ring under fluorination have been determined by the isotopic substitution method for 1,3-difluorobenzene. -The experimental work was carried out predominantly by Double Resonance Modulation (DRM) microwave spec­ troscopy, which allowed all C13-forms to be studied in their natural abundances. The normal and the 2,4,6,-d3 species were used as the parent molecules, and the resulting two sets of structure parameters are found to agree well with each other. With square brackets indicating consistency limits between the two sets of results deduced by the Kraitchman method, the following bond distances (in Å) and angles (in degrees) have been found:
C(1/3) - F(1/3) = 1.3561 [9] ≮ C(1) C(2) C(3) = 115.74 [6]
C(2) - C(1/3) = 1.3888 [1] ≮ C(2) C(3) C(4) = 123.70 [5]
C(113) - C(6/4) = 1.3745 [7] ≮ C(3) C(4) C(5) = 118.00 [2]
C(4/6) - C(5) = 1.3956 [1] ≮ C(4) C(5) C(6) = 120.86 [1]
C(2) - H(2) = 1.0822[3] ≮ C(1) C(2) H(2) = 122.13 [3]
C(4/6) - H(4/6) = 1.0820 [2] ≮ C(3) C(4) H(4) = 119.92 [1]
≮ C(2) C(1) F(1) = 117.26 [7] ≮ C(4) C(5) H(5) = 119.57 [1]
The bond lenth C(5) - H(5) was assumed as 1.082 ± 0.001 Å.
Partial Atomic Distribution Functions of Liquid Fe75B25
Authors: Mattern N. , Matz W. , Hermann H. 
Published: February 2015

Abstract
Partial structure factors and atomic distribution functions for liquid Fe75 B25 were determined for the Fe-Fe and Fe-B pairs by means of X-ray and neutron diffraction. The experimental results show a strong chemical short-range order in the melt which is similar to that of amorphous Fe75B25.
Quadrupole Hyperfine Structure in the Rotational Spectrum of Benzonitrile
Authors: Vormann K. , Andresen U. , Heineking N. , Dreizler H. 
Published: February 2015

Abstract
We reinvestigated the quadrupole coupling of benzonitrile by an improved technique of microwave Fourier transform (MWFT) spectroscopy and evaluation method. The error of the coupling constants was reduced by one order of magnitude.
Deuteron Spin -Lattice Relaxation Times in Undercooled Aqueous Potassium - and Cesium Halide Solutions
Authors: Fink W. , Radkowitsch H. , Lang E. W. 
Published: February 2015

Abstract
Aqueous emulsions of potassium-and cesium halides in cycloalkane mixtures can be undercooled at a pressure of 225 MPa to temperatures around 170K. In these emulsions deuterium spin-lattice relaxation times T1 have been determined as function of salt concentration, temperature and pressure at magnetic fields of 2.4 Tesla and 7.0 Tesla. The frequency and temperature dependence of the relaxation time curves is described quantitatively within a motional model which is consistent with known local structural features in these solutions. Model parameters deduced are compared with those obtained in related studies of the other alkali-halides, and conclusions are drawn regarding the influence of structure and composition on molecular motions.
Fréedericksz Transitions in Crossed Electric and Magnetic Fields
Authors: Barbero G. , Miraldi E. , Oldano C. , Valabrega P. Taverna 
Published: February 2015

Abstract
A homogeneously aligned nematic layer with positive dielectric and diamagnetic anisotropies, placed in crossed electric and magnetic fields orthogonal to the undistorted molecular direction, is considered. Following Deuling's procedure, the possible director field configurations are classified into four types or “phases”, characterized by distortions which are zero, pure twist, splay-bend and mixed type, respectively. It is shown that the transitions between these phases are generally of second order. Simple approximate expressions relating the critical fields and the distortion angles are given for the limiting cases of very small and very large distortions. The validity ranges of the approxima­ tions are found by comparison with the results of a numerical analysis. The experimental critical lines corresponding to three different types of phase transitions, obtained with a ZLI 1738 sample, are compared with theoretical ones. The agreement between theory and experiment is quite satisfactory.
Micro wave Spectra of Furazan I. The Doubly Determined Substitution Structure
Authors: Stiefvater Otto L. 
Published: February 2015

Double Resonance Modulation (DRM) microwave spectroscopy has been used to determine the rotational constants of isotopic forms of normal (C2H2N2O2) and perdeuterated furazan (C2D2N2O). From these data the complete substitution structures have been derived by Kraitchman methods and by the computer program GEOM. The latter procedure fails to give correct results due to the decrease of the moment of inertia about the C2v -axis and the simultaneous interchange of inertial axes in the 18O-3,4-d2-form.
The following bondlengths (in Å) and angles (in degrees) are best compatible with the total body of isotopic information:
0 - N = 1.3729 [6] ∢ NON = 111.15 [8]
N -C = 1.3032 [13] ∢ ONC = 105.53 [5]
C -C =1.4211 [9] ∢ NCC = 108.89 [3]
C -H = 1.0763 [5] ∢ CCH = 130.16 [3]
Here, the uncertainties cover small differences between normal and d2-furazan as well as discrepancies resulting from different schemes of structure calculation.
Reversible Energy Transfer and Fluorescence Decay in Solid Solutions
Authors: Twardowski R. , Kuśba J. 
Published: February 2015

Abstract
The article deals with the influence of reversible excitation energy transfer on the fluorescence decay in systems with random distribution of molecules. On the basis of a hopping model, we have obtained an expression for the Laplace transform of the decay function and an expression for the average decay time. The case of dipole-dipole interaction is discussed in detail.
Notizen: On Electromagnetic Spinors and Quantum Theory
Authors: Inskeep Warren H. 
Published: February 2015

Abstract
The Maxwell theory is related to the Dirac theory by two heuristic arguments based on electromagnetic spinors. First, given the condition to have spinors, if the free field Maxwell's equations are satisfied, then the spinors satisfy the Weyl equations. Second, a sufficient condition for electromagnetic spinors directly gives the Weyl equations with the usual substitutions for momentum and energy. It is proposed that the heuristic nature of the first argument is related to the idea of a point having a more general symmetry than a sphere.
Thermionic Electron Emission of Tungsten Bronzes. K0.30WO3 and Rb0.30WO3
Authors: Zocchi F. 
Published: February 2015

Abstract
The work functions and thermionic constants of the hexagonal tungsten bronzes K0.30WO3 (φ = 1.76 eV, A = 3 A/ cm2 K2) and Rb0.30WO3 (φ = 1.88 eV, A = 10 A/cm2 K2) are determined and compared with those of the corresponding alkaline metals and hexagonal Cs0.305WO3.
Polarized Optical Absorption and Emission of Pt (II)Complexes:Single Crystal [Pt(o-phen)(en)]Cl2 · 2H2O
Authors: Schwarz R. , Gliemann G. 
Published: February 2015

Abstract
The influence of temperature (1.9 ≦ T ≦ 295 K) on the polarized optical absorption and emission spectra of single crystal [Pt(o-phen)(en)]Cl2 · 2H2O is reported. Analysis of the spectra shows that the emission at low temperatures originates from the states of three types of traps located energetically by Δῡ ≲ 5 cm-1, 43 cm-1, and 194 cm-1, respectively, below the triplet exciton band.
Crystal Structure of Bis(trimethyltin)Selenate Dihydrateand Rotational Tunnelling of the Methyl Groups
Authors: Zhang Da , Prager Michael , Dou Shi-Qi , Weiss Alarich 
Published: February 2015

Abstract
Rotational tunnelling and librations of methyl groups in bis(trimethyltin) selenate dihydrate, [(CH3)3Sn]2SeO4 · 2 H2O, have been studied at low temperature using inelastic neutron scattering (INS) technique. Three tunnel transitions at 1.31 μeV, 3.47 μeV, and 21.0 μeV of equal intensity were recorded. In the energy range of phonons a broad, slightly structured intensity distribution is observed. An attempt is made to identify and assign librational modes. The crystal structure of the title compound was determined by single crystal X-ray diffraction. [(CH3)3Sn]2SeO4 · 2 H2O crystallizes orthorhombic, space group D14
2h-Pbcn with 4 molecules in the unit cell. The lattice constants at room temperature are a = 1142.9(3) pm, b = 1304.6(4) pm, and c = 1084.6(3) pm. According to the molecular symmetry, the two "(CH3)3Sn(H2O)" units in molecule are crystallographically equivalent, but the three methyl groups bound to one Sn-atom are inequivalent. This result coincides well with the observation of three tunnel transitions in INS. A comparison with the related compound, bis(trimethyltin) sulfate dihydrate, is presented. The existence of hydrogen bonding and the role of intermolecular interactions on rotational tunnelling are discussed.
Comment on the Chaotic Behaviour of van der Pol Equations with an External Periodic Excitation
Authors: Steeb W.-H. , Huang Jeun Chyuan , Gou Yih Shun 
Published: February 2015

Abstract
The limit cycle system with an external periodic force d2u/dt2 - a( 1 - u2)du/dt + un = kcos(Ωf) (n = 1, 3, 5,...) can show chaotic behaviour for certain values of a, k and Ω. We study the influence of n on the chaotic behaviour. For n = 1 we select values which result in chaotic motion of the system. Then we investigate the behaviour of the system for n = 3, 5 and 7. Introducing the nonlinearity un(n - 3, 5, 7) gives the surprising result that the chaotic motion ceases to exist.
Monte Carlo Simulation of Electronic Excitation Migrationand Trappingin Disordered Two-Component Systems. A Comparison with Analytical Theories
Authors: Błonski Sławomir , Bojarski Czesław 
Published: February 2015

Abstract
Monte Carlo simulations of quantum yield and anisotropy of fluorescence in two-component systems have been conducted with various donor and acceptor concentrations and Förster radii ratios RDA
O/RDD
O. The influence of excitation migration and trapping on the fluorescence of the viscous solution has been considered. The results of the simulations have shown that steady-state fluorescence of a two-component system depends on the RDA
O/RDD
O ratio as predicted in LAF theory.
Das Laser-Seitenbandverfahren: IR-Spektroskopie mit Mikrowellengenauigkeit
Authors: Kreiner W. A. , Prinz H. , Magerl G. 
Published: February 2015

Abstract
Infrared spectroscopy with laser sidebands at microwave modulation frequencies Infrared spectroscopy with laser sidebands at microwave modulation frequencies (12-18 GHz) is described. After the basics of this technique several examples of saturation spectroscopy on gaseous molecules are given. As a result it is shown that, in the infrared between 900 and 1100 cm-1 this broadband tunable laser source achieves resolution (3 parts in 109) as well as absolute accuracy in frequency measurement (± 3 x 10-6 cm-1) which are comparable to microwave spectroscopy.
Simplification of Rotational Spectra and Spectral Hole Burning by Selective Excitation Techniques in Microwave Fourier Transform Spectroscopy
Authors: Vogelsanger B. , Bauder A. 
Published: February 2015

Abstract
Selective excitation techniques have been applied to pulsed microwave Fourier transform spectroscopy. The frequency selectivity in excitation has been reached either by a long, weak pulse, or by a DANTE multi-pulse sequence. The corresponding excitation spectra calculated from a density matrix theory are in good agreement with the experimental results. The selective excitation techniques have been combined with double resonance sequences in order to simplify the recorded one-or two-dimensional spectra. Furthermore, selective excitation techniques have been applied to burn ‘holes’ into rotational transition lines broadened by an inhomogeneous Stark field.
Deuterium Quadrupole Coupling Constants in Deuterochloroacetylene
Authors: Heineking N. , Andolfatto M. , Keussen U. , Mues A. , Dreizler H. 
Published: February 2015

Abstract
The deuterium and chlorine nuclear quadrupole coupling constants have been determined for both of the chlorine isotopomers of deuterochloroacetylene (DCCC1), along with the rotational, centrifugal distortion, and chlorine spin-rotation coupling constants. The values are B = 5186.97631 (22) MHz, DJ= 1.13(2) kHz, eQq(Cl)= -79.7358(19) MHz, cI(Cl) = 1.10(31)kHz, and eQq(D) = 207.0(28)kHz for DCCCl-35, and B = 5084.17839(30) MHz, DJ = 0.99(2) kHz, eQq(Cl)= -62.8451(27) MHz, cI(CI) = 0.76(43) kHz, and eQq(D) = 205.8(39)kHz for DCCCl-37.
O 1s Core-Level Positions of Bi2Sr2CaCu2O8-x by OKα-Ray Emission
Authors: Burgäzy F. , Politis C. , Lamparter P. , Steeb S. 
Published: February 2015

Abstract
The measured O Kα X-ray emission spectrum of the high-Tc superconductor Bi2Sr2CaCu2O8-x is compared with a spectrum based on local density band structure calculations. By taking also into account the shape of the measured O 1s X-ray photoelectron spectrum an energy level diagram for the O 1s core-level binding energies of the three different oxygen sites is constructed. The O 1s binding energy in the Bi2O2-layers is found to be about the same as that one in the SrO-layers, whereas the binding energy in the CuO2-layers is lower by about 0.5 eV.
Dipole-Dipole Transport of Excitation in Liquid Solutions: Influence of Multi-Stage Energy Transfer on Donor Photoluminescence Yield
Authors: Kuśba J. 
Published: February 2015

Abstract
On the basis of expressions obtained earlier, numerical calculations of relative donor quantum yields in the presence of multi-stage dipole-dipole energy transfer and material diffusion are carried out. Transfer rates of the second order obtained from the numerical solution of the diffusion equation with reflecting boundary conditions are used in the calculations. The results reflect the influence of donor and acceptor concentration, magnitude of diffusion coefficients and molecular size effects.
Nitrogen and Deuterium Hyperfine Structure in the Rotational Spectrum of Morpholine
Authors: Grabow J.-U. , Ehrlichmann H. , Dreizler H. 
Published: February 2015

Abstract
We reinvestigated the rotational spectra of morpholine and N-deutero morpholine with the higher precision of microwave Fourier transform spectroscopy. The rotational, centrifugal, and nitrogen quadrupole coupling constants were improved and the deuterium quadrupole coupling constants determined.
Dust in the Solar System
Authors: Fechtig H. 
Published: February 2015

Abstract
Properties of cometary dust particles are better known since the space missions to Comet Halley. Their properties (densities, atomic composition) are compared with relevant observations from lunar microcraters and in-situ experiments. At 1 AU in the eliptic, 2/3 of the dust grains are normal density particles, presumably of asteroidal origin and irregularly shaped, while the remaining 1/3 are low density particles, presumably of cometary origin, but due to solar irradiation in a processed state (corresponding to “Brownlee”-particles). Beyond the asteroidal belt only black cometary dust grains are observed which have recently been released from comet nuclei orbiting on highly eccentric trajectories.
Xenon in Chondritic Metal
Authors: Marti K. , Kim J. S. , Lavielle B. , Pellas P. , Perron C. 
Published: February 2015

Abstract
We report xenon isotopic abundances observed in the stepwise release of noble gases in a highpurity metal separate of the Forest Vale (H4) chondrite. We identify a 244Pu-derived fission component, due to recoils into the metal, a cosmic-ray-produced spallation component and a new trapped component (FVM; 132Xe: 134Xe: 136Xe = 3.16:1.235:1.000) which is isotopically distinct from known solar system reservoirs. We discuss several processes which might account for observed isotopic shifts and conclude that the signature of FVM xenon may provide clues regarding the origin of chondritic metal.
The Trace Element Chemistry of the Metal in IAB Iron Meteorites
Authors: Larimer John W. , Rambaldi Ermanno R. 
Published: February 2015

Abstract
Metal grains from a silicate inclusion in Landes, a group IAB iron-meteorite, were separated and analyzed via IN A A for 14 siderophile elements. The same 14 elements were determined in matrix metal from Landes, 5 other IAB meteorites and three anomalous iron meteorites. Compared to the other samples and to chondritic metal, the inclusion metal is enriched in siderophile elements. In chondritic metal, the siderophile element contents are higher when Fe0 is oxidized to FeO. Silicates in IAB inclusions contain little FeO, yet the metal is as rich in siderophile elements as the most oxidized chondrites.
Evidently the IAB body contained its full cosmic complement of S resulting in an FeS content ~5 x that of ordinary chondrites. This explains the composition of the metal since sulfurization, like oxidation, reduces the available Fe0. IAB meteorites contain their full cosmic complement of other moderately volatile elements, which implies an equally high S content. A high S content significantly affects the melting and freezing of FeNi-metal. About 85% of the metal melts at the Fe-FeS eutectic (~960 °C), and all of the metal is molten at ~1050°C. During cooling, ~85% of the metal crystallizes with a Ni content of 6±1% between 1050°c and 960°C. Besides a small depletion in elements with low melting points or chalcophile tendencies this metal is little fractionated. Bellow 960 °C, the Ni content of the metal increases until the melt is exhausted. This Ni-rich metal also becomes progressively depleted in refractory elements and enriched in volatile elements. The crystallization process thus yields products that mimic the abundance and composition of group IAB meteorites.
Large-N Expansion for a Nucleon-Nucleon Potential
Authors: Büyükkilic Fevzi , Demirhan Dogan 
Published: February 2015

Abstract
The Schrödinger equation has been solved by \/N expan­ sion for a two nucleon system which interacts by an attrac­ tive Yukawa potential. For the ground and first excited states, energy eigenvalues have been obtained.
Magnetic Field Distribution Measurement by the Modified FLASH Method
Authors: Weis Ján , Frollo Ivan , Budinský Luboš 
Published: February 2015

Abstract
Magnetic field inhomogeneities cause blurring and distortion of images gained by nuclear magnetic resonance. In order to adjust the magnetic coils finely, a precise and rapid method for measuring the magnetic field is needed. We describe a gradient echo technique of the FLASH version for mapping static magnetic fields.
Eine Auswertmethode für DSC-Kurven binärer Gemische sowie die Phasendiagramme einige rMethylchlorsilane mit Lutidin / A New Evaluation of DSC-curves of Binary Mixtures and the Phase Diagrams of Some Methylchlorosilanes with Lutidine
Authors: Hensen Karl , Dräbing Michael 
Published: February 2015

Abstract
A new evaluation of DSC-curves of binary mixtures is given. By analyzing the phase diagrams of methyltrichlorosilane and dimethyldichlorosilane with some lutidines the existence of the incongruently melting addition compounds MeSiCl3 · (2.3-Lutidine)-,, MeSiCl3 · 2.3-Lutidine, (MeSiCl3)2 · 3.4-Lutidine, Me,SiCl2 · (2.3-Lutidine)2, Me2SiCl2 · (2.5-Lutidine),, Me2SiCl2 · 2.5-Lutidine, Me2SiCl2 · (2.6-Lutidine)2, Me2SiCl2 · 2.6-Lutidine, Me2SiCl2 · (3.4-Lutidine)2, Me,SiCl2 · 3.4-Lutidine, (Me2SiCl2)2 · 3.4-Lutidine, Me2SiCl2 · (3.5-Lutidine)2, Me2SiCl2 · 3.5-Lutidine, and the congruently melting compound MeSiCl3 ·(3.4-Lutidine)2 was proven.
Ion Dip Spectrum of the Fluorobenzene-Argon van der Waals Complex in a Supersonic Jet
Authors: Bader H. , Krätzschmar O. , Selzle H. L. , Schlag E. W. 
Published: February 2015

Abstract
The ion dip spectrum of the fluorobenzene-Argon van der Waals complex has been measured and the complex shift in the ground state is determined. The observed dips then could be assigned by comparison with the ion dip spectra and hotband spectra of the fluorobenzene molecule.
Relativistic Ground and Excited State Energies of a/1-Particle in Hypernuclei Using Woods-Saxon Potentials
Authors: Koutroulos C. G. 
Published: February 2015

Abstract
The relativistic Dirac equation with a scalar potential and the fourth component of a vector potential of the Woods-Saxon shape is solved numerically for potential parameters obtained by a last squares fitting procedure of the ground state binding energies of the Λ in a number of hypernuclei and its binding energies in the ground and excited states (as well as the relevant spacings) for various hypcrnuclei are determined. The results are in very good agreement with the preliminary experimental ones given by Chrien on the basis of the (π+, K+) reaction on nuclei.
Die isoelektronischen Molekülkomplexe TiCl3(NPPh3) und TiCl3(OSiPh3) / The Isoelectronic Molecular Complexes TiCl3(NPPh3) and TiCl3(OSiPh3)
Authors: Rübenstahl Thilo , Wolff von Gudenberg Dorothea , Weller Frank , Dehnicke Kurt , Goesmann Helmut 
Published: February 2015

Abstract
TiCl3(NPPh3) and TiCl3(OSiPh3) have been prepared from titanium tetrachloride and Me3SiNPPh3 and HOSiPh3, respectively. Both complexes were characterized by IR spectroscopy and by crystal structure determinations.
TiCl3(NPPh3): Space group R3̄̅, Z = 6, structure analysis with 959 observed unique reflections, R = 0.039. Lattice dimensions at -68°C: a = b = 1370.5(7), c = 1845.9(9) pm.
TiCl3(OSiPh3): Space group P21/c, Z = 8, structure analysis with 4549 observed unique reflections, R = 0.049. Lattice dimensions at 19°C: a = 2127.7(2), b = 947.2(1), c = 2136.8(1) pm, β = 105.081(5)°.
Both complexes form monomeric molecules in which the titanium atom is tetrahedrally coordinated by three chlorine atoms, the nitrogen atom of the phosphorone iminato ligand and the oxygen atom of the silyloxy group, respectively. The bond lengths TiN of 171.9(4) pm and TiO of 171.0(3) (in average) correspond to double bonds.