bluuebunny/crossref_metadata_2025 huggingface dataset:
The Electronic Structure of Tetraphosphorus-and Tetraarsenic- Trisulphides; Interpretation of their Photoelectron Spectra
Authors: Palmer Michael H. , Findlay Robert H.
Published: February 2015

Ab initio SCF calculations of the X1A1 ground states of P4S3 and As4S3 are reported, together with configuration interaction studies of the 2 A1, 2 A1, 2 A2 and 2 E states of P4S3. A re-interpretation of the UV-photoelectron spectrum of the P4S3 molecule, and As4S3 by analogy, is presented and it is noted that Koopmans′ theorem yields a very similar order and spacing between groups to the doublet states computed by configuration interaction.
Diode Laser Spectrum of OCS: The ν1 Band at 2062 cm–1
Authors: Klebsch W. , Yamada Koichi , Winnewisser G.
Published: February 2015

The ν1 band of OCS has been measured in the wavenumber range 2026 to 2081 cm-1 to an accuracy better than 0.0008 cm-1 using a diode laser spectrometer. The width of the observed lines is essentially Doppler-limited. The observed lines could be assigned to the following hot bands: 1110-011O, 1200-0200, 1220-0220, 1001-0001, 1111-O111 of OCS and to 1000-0000 and 1110-0110 of the isotopic species OC34S and OC33S in natural abundances. These data provide a secondary standard in this wavelength region.
On the Calculation of the Electrostatic Potentials at the Nuclei in the Point-charge Approximation
Authors: Maksić Z. B. , Rupnik K.
Published: February 2015

It is shown that the concept of atomic charge in molecules is a useful tool in studying electrostatic potentials at the nuclei which in turn are closely related to a number of molecular properties. Calculations executed on a selected set of widely different compounds provide extensive evidence that the semiempirical SCC-MO (self-consistent charge) atomic charges are equally successful in this respect as the ab initio DZ ones.
Pulsed Microwave Microwave Double Resonance Spectroscopy with Fourier Transform Technique
Authors: Bestmann G. , Dreizler H.
Published: February 2015

We present a new three and four level double resonance spectroscopy in the microwave region. A pulsed pump radiation and Fourier transform technique for detection of the signal radiation is used. This method is complementary to that using continuous microwave pump radiation.
Specific Volume and Ultrasonic Velocity Studies of the Liquid Crystal N-(p-n-hexyloxybenzylidene)-p-n-butylaniline (Hx BBA)
Authors: Choudary L. V. , Rao J. V. , Murty P. N. , Murty C. R. K.
Published: February 2015

Specific volume and ultrasonic velocity measurements have been carried out on the liquid crystal N-(p-n-hexyloxybenzylidene)-p-n-butylaniline in the isotropic, nematic, smectic A, smectic B and smectic G phases. The variation of the specific volume with temperature shows that the corresponding transitions are of first order. Thermal expansion coefficients have been calculated for all the mesophases. The ultrasonic velocity variation with temperature confirms the transitions.
The Electronic Structure of the Octa-Sulphur Molecule: An ab Initio Configuration Interaction Study
Authors: Palmer Michael H. , Findlay Robert H.
Published: February 2015

An ab initio SCF calculation of better than double zeta qualitv (192 basic functions) acted as a starting point for a configuration interaction (CI) study. The final CI with 3408 configurations showed that the 3d orbital density was reduced further than the initial value of 0.1 e; the SCF configuration was dominant, but an element of in -out correlation occurred, with incorporation of the orbital 1a2 in replacement for 1b1 being notable in many configurations.
Influence of the Static Sample Temperature on the Mass Spectra of Alkali Halides and Metals Obtained with Pulsed Laser Induced Ion Generation
Authors: Schueler B. , Feigl P. K. D. , Krueger F. R.
Published: February 2015

Experimental investigations of the interdependence between the ion yield and the static sample temperature at a fixed laser irradiance. between the ion yield and the laser irradiance at different static sample temperatures and between the ion detection threshold irradiance and the static sample temperature are reported. Laser wavelengths of 532 nm. 355 nm and 266 nm have been used to obtain the data. The laser pulse duration was 10 ns. Experimental results for alkali halides and metals are reported and compared. A strong dependence of the experimental parameters mentioned above on the static sample temperature has been observed for alkali halides. In the case of metals only minor effects have been found. In any case the different laser irradiation wavelengths do not significantly effect the experimental results.
Complicated Poincaré Half-Maps in a Linear System
Authors: Uehleke Bernhard , Rössler Otto E.
Published: February 2015

Poincaré half-maps can be used to characterize the behavior of recurrent dynamical systems. Their usefulness is demonstrated for a linear three-dimensional single-loop feedback system. In this example everything can be calculated analytically. The resulting half-maps are "benign" endomorphic maps with a complicated topological structure. This is surprising since the combination of two such half-maps (yielding an ordinary Poincaré map) always implies simple behavior in a linear system. The method has a direct bearing on the theory of piecewise linear systems -like the well-known Danziger-Elmergreen system of hormonal regulation.
Rovibrational Analysis of the ν3 Band of Diazomethane, H2CNN
Authors: Vogt Jürgen , Winnewisser Manfred
Published: February 2015

The ν3 fundamental of diazomethane. which essentially corresponds to a symmetric methylene deformation has been reinvestigated at a resolution of 0.07 cm-1 . The J- and Ka-structures of this A-type band have been resolved and analysed for the first time. The rovibrational assignment is given and, using Watson's S-reduced Hamiltonian, the rotational and quartic centrifugal distortion constants could be determined for the first excited vibrational state of the symmetric methylene deformation.
Non-Uniform Chaotic Dynamics with Implications to Information Processing
Authors: Nicolis J. S. , Meyer-Kress G. , Haubs G.
Published: February 2015

We study a new parameter - the "Non-Uniformity Factor" (NUF) -, which we have introduced in [1]. by way of estimating and comparing the deviation from average behavior (expressed by such factors as the Lyapunov characteristic exponent(s) and the information dimension) in various strange attractors (discrete and chaotic flows). Our results show for certain values of the control parameters the inadequacy of the above averaging properties in representing what is actually going on - especially when the strange attractors are employed as dynamical models for information processing and pattern recognition. In such applications (like for example visual pattern perception or communication via a burst-error channel) the high degree of adherence of the processor to a rather small subset of crucial features of the pattern under investigation or the flow, has been documented experimentally: Hence the weakness of concepts such as the entropy in giving in such cases a quantitative measure of the information transaction between the pattern and the processor. We finally investigate the influence of external noise in modifying the NUF
Weak Double Layers: Existence, Stability, Evidence
Authors: Schamel H.
Published: February 2015

Two more classes of monotonic double layers complementing the class of beam-type double layers are investigated analytically, and their range of existence is explored in the small amplitude limit. One class preferentially exists for hot ions and electron drifts of the order of electron thermal velocity. The second one, instead, assumes hot electrons and needs almost current-free conditions. The first class, called SEADL, is based on the slow electron acoustic branch and exhibits a tuning-fork configuration in the electron phase space. Its density decreases with increasing potential. The second one (SIADL) rests on the slow ion acoustic branch and. consequently, has a tuning-fork pattern in the ion phase space. Its density increases with the potential. Both classes are found to be linearly stable with respect to one-dimensional, but unstable with respect to two-dimensional electrostatic perturbations. A comparison with experiments suggests an identification of the second type with the double layers obtained by Hollenstein
X-Ray Diffraction Study on the Structure of the Metallic Glasses Mg84Ni16 and Mg30Ca70
Authors: Nassif E. , Lamparter P. , Steeb S.
Published: February 2015

The total structure factors as well as the total pair correlation functions of amorphous Mg84Ni16 and Mg30Ca70 were determined by X-ray diffraction. The Mg-Ni glass shows rather strong chemical short range ordering. By Gaussian fit of the total pair correlation function partial coordination numbers and atomic distances were obtained. Similar surrounding of the Ni atoms in the amorphous phase and in crystalline Mg2Ni was found. The structural features of the Mg-Ca glass differ from those of the Mg-Ni glass
Multiphoton Excitation in Molecular Bismuth
Authors: Babaky Omar , Topouzkhanian Ari
Published: February 2015

Two new molecular emissions have been observed at 400 nm and 250 nm in bismuth vapour after visible and infrared multiphoton absorption. A new state of even parity, labelled W and lying at more than 37600 cm-1 from the ground state, has been evidenced. Known atomic lines are also excited via dissociation of repulsive states
Absorption Spectra of Substituted 2-Phenylindan-1,3-Dion-2-YL Radicals in Solution
Authors: Zechner J. , Getoff N. , Timtcheva I. , Fratev F. , Minchef St.
Published: February 2015

Flash photolysis of a series of 2-phenylindandione-1,3 derivatives substituted in the 4′ position results in both the formation of stable benzylidenephthalides and of phenylindan-1,3-dion-2-yl radicals. The u. v. absorption maxima of these radicals are dependent on the solvent and show a bathochromic shift upon substitution. These substitution effects were correlated by means of a linear free energy relationship. Attempts were made to draw conclusions concerning the changes in the gap of the states involved and their curvature due to substitution.
The Behaviour of Population in a Plasma Interacting with an Atomic Gas
Authors: Furukane Utaro , Oda Toshiatsu
Published: February 2015

The processes leading to the population inversion are investigated in a recombining hydrogen plasma which is interacting with a cool and dense neutral hydrogen gas by using the rate equations on the basis of a collisional-radiative (CR) model and the energy equations for electrons, ions and neutral particles. The quasi-steady state (QSS) approximation is used only for the levels i lying above a certain level i* which is not the first excited level. The calculations have shown that the quasi-steady state cannot be realized while intense energy-flows due to the collisional processes exist between different kinds of the particles such as the electrons and the ions in the plasma, and that the population inversion is realized only in the quasi-steady state following the transient phase. The effects of the initial conditions of the hydrogen plasma and of the introduced neutral hydrogen gas on the overpopulation density are also discussed.
Some Considerations on the Role of Water in Thin Layer Chromatography of Inorganic Anions
Authors: Iida Takaya , Ito Kaname
Published: February 2015

The volume ratios of the mobile and stationary phases in thin layer chromatography, and the partition coefficients of halide and halate anions and some other anions between these phases were obtained by developing the ions simultaneously with a series of metaphosphates. The water contents of the developing solvents influenced the volume ratios very much, but not so much the partition coefficients. The logarithm of the partition coefficient of the halide anions is proportional to the reciprocal of their ionic radius, and that of the halate anions and oxoanions to the partial charge on the oxygens of them.
Analytical Results on a Chaotic Piecewise-Linear O.D.E.
Authors: Uehleke B. , Rössler O. E.
Published: February 2015

A variant to the well known Danziger-Elmergreen equation of hormonal regulation is analyzed geometrically by analytical methods. The new method of Poincaré half maps is employed. Several chaotic regimes are found.
Kristallstruktur und Schwingungsspektren des Di-Blei-Hexaselenohypodiphosphates Pb2P2Se6 / Crystal Structure and Vibrational Spectra of Pb2P2Se6
Authors: Becker Robert , Brockner Wolfgang , Schäfer Herbert
Published: February 2015

Pb2P2Se6 crystallizes in the monoclinic system, space group Pn (No. 13) with the lattice constants

a = 974.2 (4) pm. b = 766.2 (3) pm. c = 689.8 (3) pm, β=91.44(5)°.

The title compound is isotypic to the homologous Pb2P2S6. In the structure there are discrete P2Se4-
6 anions.

Far infrared, infrared and Raman spectra of this compound have been recorded. The observed frequencies are assigned on the basis of P2Se4-
6 units with C2h symmetry in the crystal. DTA-data have been determined and interpreted.
Improved Pseudopotential Calculations of the Adiabatic Potentials and Oscillator Strengths of Tl-Heavy Noble Gas Systems
Authors: Czuchaj E. , Sienkiewicz J.
Published: February 2015

The thallium-heavy noble gas potentials and absorption oscillator strengths as a function of internuclear separation have been recalculated using a somewhat modified Baylis' model for the electronic interaction between the atoms. The calculated potentials associated with the 62P1/2, 62P3/2 and 72S1/2 thallium states are compared to the potentials determined by Cheron et al. from the measurement of continuum emission intensities on the extreme wings of the TI resonance lines due to noble gas perturbers. The shift and broadening coefficients for the 3776 and 5350 Å lines of thallium perturbed by noble gases have also been estimated from the present potentials. The agreement with the experiment is quite good. Moreover, the very strong emission TIXe band centered at approximately 6000, 4300 and 3650 Å, as observed experimentally, can be predicted by the calculated potentials as well.
Electronic Spectra of Radical Cations and Their Correlation with Photoelectron Spectra
Authors: Khan Zahid H.
Published: February 2015

Electronic absorption spectra of the radical cations of 1.2,7.8-dibenzochrysene, 1.2,3.4-dibenzanthracene, 1.2,5.6-dibenzanthracene and 1.2,7.8-dibenzanthracene in boric acid are measured. The transition energies of the cations are calculated using the Longuet-Higgins-Pople and Wasilewski type Open-Shell-SCF-MO methods with limited CI. A comprehensive discussion of the absorption bands is given in the light of the calculations and the photoelectron spectral data for the hydrocarbons. The correspondence between the optical and photoelectron spectra is found to be extremely good with almost negligible matrix shifts, thus highlighting the role of photoelectron spectroscopy in understanding the optical spectra of the radical cations and vice versa. Finally, a correlation diagram for the observed electronic transitions for the radical cations of anthracene and its benzologs is presented from which it is inferred that the optical A-transitions have some sort of correlation with the first IP's of the respective hydrocarbons.
Pressure Dependence of the Melting and Self Diffusion in 2,2-dimethylpropane, 2,2-dimethylpropionitrile, and 2-methylpropanol-2
Authors: Woznyj M. , Prielmeier F. X. , Lüdemann H.-D.
Published: February 2015

The melting pressure curves of 2,2-dimethylpropane, 2,2-dimethylpropionitrile and 2-methylpropanol- 2 and the pressure dependence of the hex ⇔ fee transition of 2,2-dimethylpropane have been determined in the pressure range between 0.1 and 200 MPa. The self diffusion coefficients D in the liquid state of the three compounds have been determined as function of pressure (pmax ≧ 120 MPa) from the melting pressure curve up to ca. 450 K. At high temperatures and high pressures the self diffusion coefficients of the three compounds become rather similar. The influence of the hydroxylgroup upon the diffusivity of (CH3)3COD is most clearly seen at the lowest temperatures. The isobars of C(CH3)4 and (CH3)3CCN are straight lines with identical slopes. For (CH3)3COD all isobars show a curvature. From the data in the Arrhenius representation activation volumes and activation energies are derived. For C (CH3)4 the density dependence of D can be described with the rough hard sphere model.
Messung der Geschwindigkeitskonstanten der Reaktion NH2+CH4→NH3+CH3 hinter einfallenden Stoßwellen / Measurements of the Rate Constant of the Reaction NH2+CH4→NH3+CH3 behind Incident Shock Waves
Authors: Möller W. , Wagner H. Gg.
Published: February 2015

The rate constant of the reaction NH2+CH4→NH3+CH3 was measured at temperatures of about 1800 K by time-resolved UV-spectroscopy of the products behind incident shock waves. NH2 was produced by the presence and thermal decomposition of hydrazine.

The data were evaluated by fitting simulated concentration-time-profiles to the measured ones.

A mean rate constant k = (4±2) 1011 cm3 mol-1 s-1 1730 <T/K < 1950 was obtained.

The temperature dependence of the reaction is discussed.
Two-Dimensional Microwave Fourier Transform Spectroscopy
Authors: Stahl W. , Fliege E. , Dreizler H.
Published: February 2015

We performed a pulse sequence experiment utilizing a technique, which is comparable with two-dimensional NMR-spectroscopy. Some theoretical considerations based on the three-level Bloch equations are given. This double resonance technique may be useful for the assignment of complicated spectra.
Variationally Determined Occupation "Numbers" in an Extended Thomas-Fermi Scheme
Authors: Müller A. M. K.
Published: February 2015

Thomas-Fermi theory is generalized by the introduction of an occupation distribution function f(s). The ansatz f(s) = Ɵ (s1 - s) of the conventional TF theory is derived from a variational principle. The implications with respect to the density functional theory are discussed. Future work is intended to include interaction, leading to deviations from the step function, which will account for correlation effects.
Weak Non Linearity and Magneto-Acoustic Waves
Authors: Bhattacharyya Sikha , Choudhury Rajkumar Roy
Published: February 2015

We show that the property of a linear system viz, the fact that square of the amplitude propagates with the group velocity continues to be valid in the case of magneto acoustic waves in the presence of weak non linearity.
Hamiltonian Formulation of Two-Dimensional Gyroviscous MHD
Authors: Morrison Philip J. , Caldas I. L. , Tasso H.
Published: February 2015

Gyroviscous MHD in two dimensions is shown to be a Hamiltonian field theory in terms of a non-canonical Poisson bracket. This bracket is of the Lie-Poisson type, but possesses an unfamiliar inner Lie algebra. Analysis of this algebra motivates a transformation that enables a Clebsch-like potential decomposition that makes Lagrangian and canonical Hamiltonian formulations possible.
Quadrupole Hyperfine Structure of the Direct l-Type Doubling Spectrum of Hydrogen Cyanide by Microwave Fourier Transform Spectroscopy
Authors: Fliege E. , Dreizler H. , Cox A. P. , Hubbard S. D.
Published: February 2015

The direct l-type doublet transitions for ν2= 1 of HCN. DCN and DC15N have been measured between 4 and 16 GHz under very high resolution by microwave Fourier transform spectroscopy. Analysis of the nitrogen-14 hyperfine structure of the transitions of HCN and DCN has required an extension of the Hamiltonian previously used. Accurate values of the 1-type doublet constants are reported.
Near Infrared Absorption of Pure Carbon Dioxide up to 3100 bar and 500 K. I. Wavenumber Range 3200 cm-1 to 5600 cm-1
Authors: Buback M. , Schweer J. , Tups H.
Published: February 2015

Near infrared absorption of pure CO2 in the v1 + v3, 2v2
0 + v3 Fermi diad region around 3650 cm-1 and in the 2v1 + v3, v1 + 2v2
0 + v3, 4v2
0 + v3 Fermi triad region around 5000 cm-1 was measured at temperatures between 298 K and 500 K to a maximum pressure of 3100 bar. Density tuning of Fermi resonance is studied and compared with literature data on gaseous, liquid, and solid CO2. Band maximum positions determined within an extended temperature and density range indicate appreciable rotational freedom up to about the critical density (0.45 g · cm-3) and repulsive interactions clearly coming into play above 0.9 g · cm-3. The vibrational intensity of the Fermi triad, up to about 1.0 g · cm-3 is found to be independent of temperature and pressure within ± 2.5%, wich enables (pure) CO2 concentrations in a large region of states to be precisely and directly measured via quantitative high-pressure high-temperature near infrared spectroscopy.
Notizen: Existence and Uniqueness of Solutions of Piecewise-Defined Continuous Dynamical Systems
Authors: Kahlert Claus
Published: February 2015

The question of existence and uniqueness of trajectories in piecewise-defined autonomous dynamical systems is investigated. Examples of prototype equations violating existence and/or uniqueness are presented as well as criteria testing these properties.
Resonances and Torsion Numbers of Driven Dissipative Nonlinear Oscillators
Authors: Parlitz Ulrich , Lauterborn Werner
Published: February 2015

The torsion of the local flow around closed orbits and its relation to the superstructure in the bifurcation set of strictly dissipative nonlinear oscillators is investigated. The torsion number describing the twisting behaviour of the flow turns out to be a suitable invariant for the classification of local bifurcations and resonances in those systems. Furthermore, the notions of winding number and resonance are generalized to arbitrary one-dimensional dissipative oscillators.
Investigation of the 14N Quadrupole Hyperfine Structure and the Stark Effect of Methyl Isocyanate and Methyl Isothiocyanate by Microwave Fourier Transform Spectroscopy
Authors: Kasten W. , Dreizler H.
Published: February 2015

The nitrogen 14N quadrupole hyperfine structure and the Stark effect in the rotational spectra of methyl isocyanate and methyl isothiocyanate were investigated by high resolution microwave Fourier transform spectroscopy.

The components of the coupling tensor in the principal inertia axis system and the n a components of the dipole moments have been determined.
The Dynamic Behaviour of a Crystal During Defect Jumps
Authors: Vogelsang R. , Hoheisel C.
Published: February 2015

In continuation of a previous paper, M D simulations of vacancy jump in an fcc-lattice have been performed, due to an increased averaging process, quantitative results for a number of correlation functions are obtained, which throw light on the details of the highly cooperative mechanism of vacancy jumps involving some fifty neighbouring particles. This Part II is mainly concerned with self correlation functions while part III focusses on distinct correlation functions. Both the mean square displacements and the velocity correlations of the particles have been considered and were analysed in comparison with those of a pure crystal and a pure fluid of high density.
An ESR Study of Structural Phase Transitions of(NH4)2Pb[Cu(NO2)6]
Authors: Asaji Tetsuo , Prabhumirashi Laxman Shrikrishna , Nakamura Daiyu
Published: February 2015

The structural changes of (NH4)2Pb[Cu(NO2)6] crystals during the phase transitions at 316, 287, and 95 K were studied by means of a single crystal ESR technique. Anisotropic g values [g∥ > g⊥) were obtained in the lowest temperature phase IV, whereas the ESR spectra recorded in the intermediate phases III and II, in which the crystal is known to be tetragonally compressed along the c axis, could be interpreted by use of effective g values [g(∥c) < g(⊥c)]. In the highest temperature phase I an isotropic g value was obtained. The phases I, II, and III o f the present complex can be assumed to be very similar to the corresponding phases observed above ~ 250 K for the compounds R2Pb[Cu(NO2)6] with R = K, Rb, Cs, and Tl. However, the lowest temperature phase transition transforms the phase III with an antiferrodistortive order of the elongated [Cu(NO2)6]4- octahedra into the phase IV with a ferrodistortive one. This occurs only for the complex with R = NH4 and is very unusual. The results of the 14N NQR experiments already reported for the phases III and IV could be well explained by the present newly proposed model.
Sternheimer Antishielding Functions ß(r) and γ(r) for Rare Earth Atoms
Authors: Sen K. D. , Schmidt P. C. , Weiss Alarich
Published: February 2015

The Sternheimer shielding-antishielding functions ß(r) and γ(r) are reported for all the fourteen lanthanide atoms at the uncoupled Hartree-Fock level of theory. Each atom is considered in two valence state configurations, 4fn 5d0 and 4 fn-1 5d1, and the nonrelativistic HF wave functions have been used. The 5d1 configuration leads to a smaller net antishielding than the 4fn configuration by ~ 6-12% in the series. The electron-electron self consistency effects are found to be less than 5% in the series. The importance of the calculated antishielding functions in the antishielding theory of electric field gradients in noncubic metals is discussed.
Impurity Quadrupole Interaction in Light Rare Earth Metals: 111Cd in La, Pr and Nd
Authors: Forker M. , Freise L. , Simon D.
Published: February 2015

The nuclear quadrupole interaction of dilute

light rare earth (RE) metals La, Pr and Nd by time differential perturbed angular correlation
measurements. The quadrupole frequency νQ has been determined in Pr as a function of
temperature and pressure, in Nd as a function of temperature, and in La at 19 K. The pressure
dependence of νQ of 111Cd in Pr ((d In νQ/d P)290 K = + 2.7 (2.3) · 10-3 Kbar-1) is a factor of
3 - 4 weaker than in the heavy RE metals Gd to Er. At the same time the temperature dependence
of νQ in the light RE is up to a factor of 3 stronger than in the heavy RE. Between 300 K and
900 K. the quadrupole frequency is a linear function of temperature with the same slope
(d In νQ/dT)290 k = - 8.4(2) · 10-4 K-1 both in Pr and Nd. Between 25 K and 300 K the decrease is stronger than linear, and more pronounced in Pr than in Nd. The temperature coefficient
(d In νQ/dT)290 k is found to decrease linearly with the RE atomic number across both the series
of the fight and the heavy RE metals.
Exploring Crystal Symmetry for the Determination of EFG-Tensors from NMR-NQR Rotation Patterns
Authors: Kind R.
Published: February 2015

In contrast to the properties of the symmetry of the nucleus under consideration the

information contained in the crystal symmetry is rarely used for the determination of EFG-tensors
from NMR-NQR rotation patterns. This information is, however, extremely useful since
already the presence of a single symmetry different from Ī
provides all necessary information in a
single rotation pattern. This is the case for all Bravais lattices except the triclinic one. It is shown
how the crystal symmetry can be explored even in the case of an arbitrary direction of the
rotation axis with respect to the crystal axes.
35Cl NQR Spectroscopy on Salts and Molecular Compounds of Trichloroacetic Acid
Authors: Fichtner Winfried , Markworth Axel , Weiden Norbert , Weiss Alarich
Published: February 2015

The temperature dependence of salts M(1)H(Cl3CCOO)2 and molecular compounds of trichloroacetic acid with amines and benzaldehydes, TCA · X, was studied,

The data fit rather well to the known dependence of the mean frequency shift Δ  on the pkadifference of X with respect to TCA. A linear relation is observed between the bleaching out temperature Tb of the 35Cl NQR lines and Δ  for M(1)H(Cl3CCOO)2 and for TCA · X, X = benzaldehydes.
Line Width Narrowing with 14N Nuclear Quadrupole Resonance Lines at 296 K and 77 K Using a High Powered Pulsed Spectrometer
Authors: Trepanier R. J. , Whitehead M. A.
Published: February 2015

The dependence of the NQR line width on the RF pulse intensity and period using a continuous steady state pulse train for polycrystalline 14N compounds shows a dependence on the asymmetry parameter η, the temperature, and the crystal structure.
Optical Detection of NQR: Crystal Field and Matrix Effects on Halogenated Organic Molecules
Authors: Borczyskowski C. v.
Published: February 2015

Electron spin polarization or alignment achieved in the excited triplet state of organic molecules can be transferred into nuclear spin polarization (alignment) during an optical pumping cycle. Due to this effect, quadrupole resonance (NQR) investigations of nuclei with concentrations of 10-5 molar are possible in the electronic singlet ground and excited triplet state in one and the same experiment by the applied optical pumping cycle. By this conventional NMR sensitivity is enhanced by several orders of magnitude, enabling investigations of defect site structures in molecular crystals.
Direct Measurements of the Isotope Exchange Reactions between 18OH and NO, NO2, N2O and O2
Authors: Dransfeld P. , Lukacs-Paal J. , Wagner H. Gg.
Published: February 2015

The isotope exchange reactions between 18OH and NO, NO2, N2O and O2 were studied at room temperature in a discharge flow system with laser magnetic resonance detection of 18OH and 16OH. Exchange rate constants of

where obtained for NO and NO2, respectively. Upper limits of k < 1 · 108 cm3/mol s can be reported for the reactions

The results are compared with recombination rate data in the limit of high pressures and with vibrational deactivation measurements.
The Hydration of Tungstate and Molybdate Ions in Aqueous Solution
Authors: Johansson Georg , Caminiti Ruggero
Published: February 2015

The structure in aqueous solution of the hydrated tungstade and molybdate ions WO4
2- and MoO4
2- has been derived from large angle X-ray scattering measurements using MoO4
2- as an isomorphous substituent for WO4
2- The W(Mo)-O bond lengths are 1.786 Å and do not differ from those found in crystal structures. A fairly well-defined hydration shell of about 12 water molecules surrounds the XO4
2- ions at a W(Mo)-H2O distance of 4.06 Å.
Nonuniform Chaotic Dynamics and Effects of Noise in Biochemical Systems
Authors: Herzel H. , Ebeling W. , Schulmeister Th.
Published: February 2015

Biochemical models capable of sustained oscillations and deterministic chaos are investigated. Chaos is characterized by exponential separation of near-by trajectories in the long-term average. However, we observed rather large deviations from purely exponential separation termed "nonuniformity". A quantitative description and consequences of nonuniformity are discussed.

Furthermore, the influence of short-correlated noise is treated using next-amplitude maps and Lyapunov exponents. Drastic amplification of fluctuations in non-chaotic systems and relative robustness of chaos were found.
Zum Circulardichroismus von Disulfidbrücken in Proteinen. Teil 2. Vergleichende CNDO/S- und INDO/S-CI-Rechnungen
Authors: Schleker Wolfgang , Fleischhauer Jörg
Published: February 2015

Rotatory strengths for H2S2 conformers based on X-ray data for ribonuclease A, 2-, and 4-zinc-insuline-dimers have been calculated with some CNDO/S- and INDO/S-versions. The best agreement between their calculated signs and those predicted by the quadrant rule and Rauk’s valence basis set ab initio calculations are found with the CNDUV-version of CNDO/S. A choice of β0
s = - 11.5 eV within this method improves the calculated transition wavelengths compared to observed ones.
Interpretation of Lamellar Electron Diffraction Data from Phospholipids
Authors: Dorset Douglas L. , Massalski Andrew K. , Fryer John R.
Published: February 2015

Lamellar electron diffraction intensity data from a series of optically active 1,2-diradyl phosphatidylethanolamines were used to determine the probable crystal packing, based on translational fitting of the molecular conformation found in the x-ray crystal structure of a dilauroyl homolog. All crystal structures are shown to be similar to one another. A packing model similar to that found from the analysis of lamellar x-ray data from the dimyristoyl homolog is obtained when the measured electron diffraction data are corrected for the curvilinear lamellar deformations seen in direct low dose lattice images.
X-Ray Diffraction Study on the Structure of Molten MgxZn(100 -x)-Alloys
Authors: Bühler E. , Lamparter P. , Steeb S.
Published: February 2015

By means of X-ray diffraction in transmission the molten MgxZn(1oo-x)-alloys (x = 0, 8, 15, 30, 40, 50, 60, 70, 73, 80, 90, 100) were investigated and the total structure factor S (Q) , the total pair correlation function, the number of nearest neighbours as well as the atomic distances were evaluated. For 30 ≦ x ≦ 80 a premaximum in S (Q) was observed which is caused by chemical short range order. The comparison of the premaximum of the Mg70Zn30-melt with that of the corresponding amorphous alloy shows that within the melt the chemical short range order amounts to about 40% of that of the amorphous alloy.
Electrical Transport Properties of Polycrystalline Chromium Vanadate
Authors: Gupta Shubha , Yadava Y. P. , Singh R. A.
Published: February 2015

Electrical transport properties of polycrystalline chromium vanadate (CrVO4) have been studied by measuring its a. c. and d.c. electrical conductivities, thermoelectric power and dielectric constant in the temperature range 300-1000 K. CrVO4 is a p-type semiconductor with an energy gap of 3.6 eV. The compound exhibits extrinsic nature up to 750 K and after that its intrinsic nature arises. The activation energy and charge carrier mobility in the temperature ranges 300-750 K and 750- 1000 K show that the conduction in the extrinsic region is due to a small polaron hopping mechanism and in the intrinsic region it is of the normal band type.
Conformational Behaviour of Phenylpyrroles — a Semiempirical Molecular Orbital Study
Authors: Fabian Walter
Published: February 2015

Equilibrium twist angles and rotational barriers for the three isomeric phenylpyrroles were calculated by means of MNDO and AM1. In each case MNDO incorrectly predicts the perpendicular conformation as the most stable one. In agreement with experimental evidence AM1 predicts only slight deviations from planarity and very low 0°-barriers (1-phenylpyrrole: 0 = 28°, E = 1.6 kJ mol-1; 2-phenylpyrrole: θ = 27°, E = 0.8 kJ mol-1; 3-phenylpyrrole: θ = 19°, E = 0.2 kJ mol-1). The reasons for the complete failure of MNDO are analyzed by partitioning the total energy into one- and two-center terms. The most significant improvement of AM1 over MNDO is found to be the much better description of repulsive interactions between nonbonded atoms. Possible further improvements of AM1 are briefly discussed.
Notizen: Comparison Between a Generic Reaction- Diffusion Model and a Synergetic Semiconductor System
Authors: Parisi J. , Peinke J. , Röhricht B. , Rau U. , Klein M. , Rössler O. E.
Published: February 2015

This paper gives a concrete physical interpretation of a simple dynamical model based on the universal Rashevsky- Turing theory of symmetry-breaking morphogenesis in terms of spatio-temporal nonlinear transport phenomena in a synergetic semiconductor system.
A Study of the Liquid Structure of Dimethyl Sulfoxide by the X-Ray Diffraction
Authors: Itoh Sumiko , Ohtaki Hitoshi
Published: February 2015

The liquid structure of dimethyl sulfoxide (DMSO) was investigated by X-ray diffraction. The intramolecular structure parameters were obtained as follows: S = 0 150(1) pm, C - S 180(1) pm, nonbonding C · · · O 267(4) pm and C · · · C 271 (7) pm. It is suggested that the molecular arrangement in the liquid state is similar to that in the solid state. It is pointed out that not only the value but also the position of the dipole mom ent vector in the molecule is essential for dipoledipole intermolecular interactions and that the latter factor results in a higher melting point of DMSO than of N ,N -dimethylformamide in spite of their similar dipole moments.
Wechselwirkung von Neutronen mit Wolfram und seinen Isotopen
Authors: Knopf K. , Waschkowski W.
Published: February 2015

The coherent neutron scattering lengths and total cross sections of elemental and oxide samples of natural and isotopically enriched W are determined. From these results the following coherent scattering lengths, b, and absorptions at 0.0253 eV, σγ were deduced:

b (natW) = 4.86±0.02 fm, σγ = 17.3 ±0.5 b ,

b (182W) = 7.04±0.04 fm, σγ = 19.6±0.3 b ,

b (183W) = 6.59±0.04 fm, σγ = 10.5±0.2 b ,

b (184W) = 7.55±0.06 fm, σγ = 1.7±0.1 b ,

b (186W) = -0 .7 3±0.04 fm, σγ = 38.5 ±0.8 b .

By comparison with the resonance parameters, the incoherence and the potential radii are derived and discussed. The bound level on W-182 must be fitted with a scattering width of gI0
n = 161 meV at E0 = - 94 eV.
Origin of Biomolecular Chirality. Analysis of Frank’s Model
Authors: Babović V. , Gutman I. , Jokić S.
Published: February 2015

Frank ’s model for biochemical L-D stereoselection is examined and approximate analytical solutions of its generalized form are deduced, extending earlier results of Frank and Tennakone.
Anthracene Adsorbed at the Solid/Liquid Interface.A2H-NMR Study of the Dynamics and Structure
Authors: Neue G.
Published: February 2015

2H-NMR relaxation time studies were performed on the adsorption system anthracene + cyclo-hexane/graphite at 295.2 K. Translational and rotational diffusion coefficients are determined for adsorbed anthracene molecules. No trace of rotational anisotropy with respect to the surface was found rendering the term orientation meaningless for a description of the structure of the adsorbed layer. Instead, a model is proposed viewing the solvent as the primary component forming a foam-like hollow structure on top of the solid, where each cavity contains an anthracene molecule which performs almost isotropic rotational diffusion.
1H and 19F NMR Study of Ammonium Ion Motion in Ammonium Trifluorostannate (II)
Authors: Hirokawa Kiyofumi , Furukawa Yoshihiro
Published: February 2015

The temperature dependences of the second moment and spin-lattice relaxation time of 1H and 19F NMR were measured on ammonium trifluorostannate (II) NH4SnF3. It was found that the NH4
+ ions having a C3 symmetry in the crystal undergo overall reorientations with an activation energy of 22 kJ mol - 1.
Distortions in Power Spectra
Authors: Merke Ilona , Dreizler Helmut
Published: February 2015

Power spectra are commonly used in microwave Fourier transform spectroscopy. We point out distortions, which may lead to erroneous frequency measurements.
TheInfrared Spectrum of CS2in the ν3Band Region
Authors: Winther Flemming , Heyne Ursula , Guarnieri Antonio
Published: February 2015

A total number of 24 bands of the carbon disulfide isotopomers 32S2
12C, 34S12C32S, 33S12C32S, 34S2
12C, 32S2
13C, and 34S13C32S between 1555 and 1455 cm - 1 have been investigated. Vibrational frequencies and rotational constants have been determined for the bands.
Radiofrequency Microwave Double Resonance Experiments in Fourier Transform Technique
Authors: Heineking N. , Stahl W. , Dreizler H.
Published: February 2015

Radiofrequency microwave double resonance has proved as a valuable method in microwave spectroscopy in the frequency domain. We present comparable experiments in the time domain Fourier transform spectroscopy.
Molar Volumes of LiNO3-Ca(NO3)2 and LiNO3-Ba(NO3)2 Melts
Authors: Igarashi Kazuo , Shimada Mutsumi , Mochinaga Junichi
Published: February 2015

The molar volumes of molten LiNO3-Ca(NO3)2 and LiNO3-Ba(NO3)2 mixtures were measured dilatometrically and are represented as functions of composition and temperature.
On the Occurance of Stereoisomeric Effects in the Dielectric Relaxation Behaviour of Pure Liquid
Authors: Dachwitz E. , Stockhausen M.
Published: February 2015

In order to find out whether liquids consisting of pure enantiomers of a chiral molecule differ in their dielectric relaxation behaviour from that of corresponding racemic mixtures, the complex permittivity of the following pure substances was measured over a broad frequency range (3 MHz to 72 GHz) at 20° CC: Phenylethylisocyanate, carvone, fenchone, 2-octanol, 2-amino-l-butanol, diethyltartrate and diisopropyltartrate. With the achieved experimental resolution, no stereoisomers effect could be observed with the exception of the tartrates, where there are clear differences in the low frequency features of the enantiomers as compared to the racemic mixture, which very probably are an association effect.
On the Global Quantum Dynamics of Multi- Lattice Systems with Non-linear Classical Effects
Authors: Duffner E. , Rieckers A.
Published: February 2015

The microscopic dynamics for a class of long range interacting multi-lattice quantum systems is constructed in the thermodynamical limit by means of operator algebraic concepts. By direct estimations the existence of the limiting Schrödinger dynamics is proven for a set of states, which comprises also globally non-equilibrium situations. The expectation values of the classical observables in the pure phase states are shown to satisfy a set of coupled non-linear differential equations. The limiting Heisenberg dynamics is derived as a W*-automorphism group in the partially universal von Neumann algebra which corresponds to the selected set of states; it is in general, however, not σ-weakly continuous in the time parameter.
Fluoreszenz -Untersuchungen an Distyrylbenzolen
Authors: Oelkrug Dieter , Rempfer Klaus , Prass Ellen , Meier Herbert
Published: February 2015

The absorption and fluorescence of three isomeric distyrylbenzenes are investigated as function of temperature. From the fluorescence decay times and fluorescence quantum yields two classes of oligostyrylarenes can be distinguished. A decisive criterion for this classification is, whether the first excited singlet state S1 belongs to an allowed or forbidden transition S0→S1.
Microwave Spectra of Furazan II. Nuclear Quadrupole Coupling in d1-Furazan
Authors: Stiefvater Otto L.
Published: February 2015

The nuclear quadrupole coupling constants for the two nitrogen atoms in monodeuterated furazan (C2HDN2O) were determined from the hyperfine structure of eight rotational transitions with low J-values. The coupling constants along the inertial axes are:

χaa (2) = + 3.546(10) MHz, χaa (5) = -5.044(10) MHz,

χbb (2) = -4.690(10) MHz, χbb (5) = + 3.900(10) MHz,

χcc (2) = + 1.144(10) MHz, χcc (5) = + 1.144(10) MHz.

In conjunction with structural information from the preceding study, these data yield the principal coupling constants, with 3er-uncertainties, as:

χR(2/5) = - 5.53 (4) MHz,

χT(2/5) = + 4.39(4)MHz,

χR(2/5) = + 1.14(4) MHz.

The radial electric field gradients deviate from the direction of the external bisector of the ring angle ONC by 24.6° towards the oxygen atom.

These results are in qualitative agreement with previous work by NQR spectroscopy and with the results of ab initio molecular orbital calculations.
Theoretical Studies of the Electric Field Gradient in Hexachlorometallates
Authors: Borchers Dirk , Schmidt Peter C. , Weiss Alarich
Published: February 2015

The electric field gradient (EFG) at the chlorine site is calculated for cubic compounds of the K2PtCl6-type (space group Fm3m), M2
IMIVCl6, where M1 is an alkali metal and MeIV a tetravalent element. In the calculations the total EFG is subdivided into the contribution of the complex [MIVCl6]2-, EFGcomplex, and the contribution of the ions outside the complex, EFGlattice. EFGcomplex is calculated by the local electron density formalism using the MS-Xα-method, and EFGlattice is determined by the point charge model.

It is found that EFGcomplex is positive whereas EFGlattice is negative. Including antishielding effects, the magnitude of EFGlattice is about one fourth of EFGcomplex. The trends in the EFG for the various compounds found theoretically are the same as the trends in the experimental nuclear quadrupole coupling constants e2Q q/h. However, the absolute values of EFGtheo are smaller than the values EFGexp deduced from e2Q q/h.

For a fixed central atom MIV the (positive) EFGexp is increasing with increasing radii of the cations (and increasing lattice constant). This increase can be understood by an increase of EFGlattice.

On the other hand, for fixed cations and different tetravalent metal atoms, the EFG is increasing with increasing electronegativity of the central atom. This can be understood by an increase of EFGcomplex. For distorted octahedra it is found that the change in the EFG due to the distortion is also due to a change in EFGcomplex.
Notizen: Supplements to Enumeration of Benzenoid and Coronoid Hydrocarbons
Authors: Wenjie He , Wenchen He , Qixiang Wang , Brunvoll J. , Cyvin S. J.
Published: February 2015

The previous report on enumeration and classification of benzenoids and coronoids is supplemented. Perhaps the most significant contribution is the enumeration of benzenoids with 12 hexagons.
The Triply Determined Substitution Structure of 1,3,4-Thiadiazole by DRM Microwave Spectroscopy
Authors: Stiefvater Otto L.
Published: February 2015

Double Resonance Modulation (DRM) microwave spectroscopy has allowed the determination of the complete substitution structure of normal, mono-deuterated and perdeuterated 1,3.4-thiadiazole (N2C2H2S). The shift of the centre of gravity between the normal and the d2-form and the swing of inertia! axes relative to the C2v symmetrical forms in the 2-d1-species have been used to revise the small coordinates of hydrogen and deuterium atoms.

Bond lengths (in Å) and bond angles (in degrees), with uncertainties covering all three molecular forms, are found as follows:

The results suggest that the shift and the swing of inertial axes between different ‘parent’ forms, which can both be determined from the moments of multiply substituted molecular isotopes, may be used with advantage to refine the position of near-axis atoms.
Higher Order Modes as Accuracy Limiting Factor in Permittivity Measurements of High Lossy Fluids Using Transmission Techniques in the GHz Range
Authors: Redhardt A. , Steinhoff H.-J. , Schütter J. , Neumann H.-J. , Hess G.
Published: February 2015

The higher order mode distortion in measuring dielectric constants on high lossy, high permittivity liquids in the GHz range is investigated by a simulation procedure as well as by experiment. For this, a homodyne method for measuring ε* is introduced in analogy to precision EPR-work.
Crystalline and Liquid Phases in the Systems MeX2/Aniline/Water (Me-Ni,Co;X=NO,ClO4)
Authors: Mahr Michacl , Paulus Helmut , Weil Konrad G.
Published: February 2015

Nickel nitrate, nickel Perchlorate and cobalt nitrate can form homogeneous liquid phases with aniline and water. The shapes of the single phase regions in the ternary phase diagrams were determined. Five types of crystals were obtained in the system nickel nitrate/aniline/water. The structures of Ni(NO3)2 · 6C6H7N · 2H2O, Ni(NO3)2 ·4C6H7N · 2H2O , and Ni(NO3)2 ·2C6H7N · 4H2O have been determined by single crystal X-ray diffraction. All structures show chains of nickel ions and nitrate ions connected by water or aniline molecules. They can be interpreted as one dimensional ion pairs.
Mechanism of Energy Transfer in Collisional Activation of Kiloelectron-Volt Macromolecular Ions
Authors: Uggerud Einar , Derrick Peter J.
Published: February 2015

An impulsive collision theory explains why helium is an effective target gas for collisionally activated decomposition of large biological ions.
Confirmation of the Electric Field Gradients at the Nitrogen Nuclei in N-Cyanomethanimine, CH2NCN, from Low-J Rotational Transitions
Authors: Stolze W. H. , Sutter D. H. , Wentrup C.
Published: February 2015

The results of a high resolution microwave study of low-J rotational transitions of N-cyano-methanimine are reported. The 14N quadrupole coupling constants fitted to the observed hyper­ fine splittings are:χaa (imine) = 2.032(9) MHz, χbb(imine) = -4.586(7) MHz, and / χaa(nitrile) = -3.254(8) MHz, χbb(nitrile) = 0.844(16) MHz. Knowledge of these constants together with the rotational constants and centrifugal distortion constants determined earlier provides the basis for accurate prediction of hitherto unmeasured rotational transitions for radioastronomy.