bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of the Dielectric Relaxation Behaviour of Water by Added Alcohols
Authors: Lux A. , Stockhausen M.
Published: February 2015

The dielectric relaxation of water rich aqueous solutions of ethanol, ehtylene glycol, glycerol, diethylene glycol, 1,2-butanediol, 1,3-butanediol and 1,4-butanediol has been measured at 20 °C. In all cases the fitting of the data by a sum of Debye type spectral components allows for two description modes which can be interpreted as a collective alteration of the water relaxation or, on the other hand, as formation of a microheterogenous solution where "affected" and "unaffected" water becomes discernible
Lattice Vibrations, MIR and FIR Optical Properties of Boron and Icosahedral Boron-Rich Borides II. β-Rhombohedral Structure Group
Authors: Werheit H. , Haupt H. , Higashi I.
Published: February 2015

The lattice vibrations of the ß-rhombohedral boron structure group are investigated in detail by group theory. IR spectra of pure ß-rhombohedral boron as well as of B: Mn, B: Fe, B: Cu, and B: Cu/Al are presented and discussed. In comparison with boron carbide most of the absorption bands can be associated with certain vibrations. The vibration frequencies are determined by application of the phenomenological theory of Waser and Pauling, which thus yields a reliable estimation of the restoring forces ion these solides
Hydrogen in Electrodynamics. V. Dirac-Hydrogen by Means of New Operators
Authors: Sallhofer Hans
Published: February 2015

After a discussion of the one-component Schrödinger (1926) and the four-component Dirac (1928) representation of hydrogen it is shown that the six-component electrodynamic picture is considerably simpler and clearer. The computational effort is reduced to a fraction
Report: Nonequilibrium Phase Transitions of Impact Ionization Breakdown in Extrinsic Semiconductors
Authors: Parisi J. , Peinke , J. , Rau U. , Clauß W.
Published: February 2015

In the study of semiconductor electronic breakdown we observe the self-generated formation of spatio-temporal dissipative structures, when a bias voltage is applied at liquid-helium temperature. The underlying nonlinear physics of impurity impact ionization reveals critical phase transition behavior by varying the temperature at constant voltage
The 14N Nuclear Quadrupole Coupling Tensors, the Tensors of the Molecular Magnetic Susceptibility and the Molecular Electric Quadrupole Moment in Pyrazole: A High Resolution Rotational Zeeman Effect Study
Authors: Böttcher O. , Sutter D. H.
Published: February 2015

High resolution zero field and Zeeman rotational spectra of 1 D-pyrazole have been studied by microwave Fourier-transform spectroscopy. The zero field hfs patterns allowed to improve the quadrupole coupling constants for both 14N nuclei. From the high field Zeeman multiplets the diagonal elements of the g-tensor were obtained as gaa= -0.1178(2),.gbb=-0.0762(2) and gcc = 0.0608 (2). The two independent components of the molecular magnetic susceptibility anisotropy in units of 10-6 erg G-2 mole- 1 are 2 ξaa - ξbb - ξcc= 52.69(32) and 2 ξbb - ξcc - ξaa = 39.32(29) were, a, b, c denote the molecular principal inertia axes. From these values the components of the molecular electric quadrupole moment tensor in units of 10-26 esu cm2 follow as Qaa = 5.84(22), Qbb= -0.58 (21) and Qcc= -5.27(38). Comparison with corresponding values for the undeuterated species leads to the complete tensors including their orientation with respect to the nuclear frame.
Franck-Condon States of Coumarins in Alcoholic Solutions
Authors: Bączyński A. , Targowski P. , Ziętek B. , Radomska D.
Published: February 2015

The temperature dependence of the fluorescence spectra of coumarin 2, coumarin 10 and coumarin 120 in ethyl alcohol is investigated. A blue-shift of the spectra with increase of temperature is observed. The blue-shift is explained by means of excited and ground Franck-Condon state parameters obtained by the adjustment of analytical shape factors to experimental spectra.
Hydrogen in Electrodynamics. VI The General Solution
Authors: Sallhofer Hans
Published: February 2015

After a discussion of the one-component Schrödinger (1926) and the four-component Dirac (1928) representation of hydrogen it is shown that the six-component electrodynamic picture turns out to be considerably simpler and clearer. The computational effort is reduced to a fraction.
Maxwell's Equations and Shear Waves in the Vortex Sponge
Authors: Kelly Edward M.
Published: February 2015

The vortex sponge is a fluid substratum which is criss-crossed by innumerable fine hollow vortex tubes. Bending of tubes causes them to drift; the combination of drift and bending turns out to have effects mathematically identical to those of electric and magnetic fields. Thus, electromagnetism can be viewed mechanically, with Maxwell's curl equations governing the translation and rotation of the substratum. Shear and shear waves are illustrated by a plane shear wave.
A New Intracrystalline Isotope Effect: 18O under the Faces of Amethyst
Authors: Klemm A. , Banerjee A. , Hoernes S.
Published: February 2015

The concentration of 18O within well formed crystals of amethyst was found to vary beneath the different growth faces, increasing in the order z→ r→m. The 18O/16O fractionation factor between the faces m and z was measured as 1.0007.
Existence of Nowhere Differentiable Boundaries in a Realistic Map
Authors: Kittel A. , Peinke J. , Klein M. , Baier G. , Parisi J. , Rössler O. E.
Published: February 2015

A generic 3-dimensional diffeomorphic map, with constant Jacobian determinant, is proposed and looked at numerically. It contains a lower-dimensional basin boundary along which a chaotic motion takes place. This boundary is nowhere differentiable in one direction. Therefore, nowhere differentiable limit sets exist generically in nature.
Notizen: On the Change of Colour of Rhodochrosite, MnCO3 on Irradiation
Authors: Banerjee A.
Published: February 2015

The change of colour of rhodochrosite on irradiation is discussed. A possible cause of the phenomenon is indicated.
Notizen: Non-coincidence of Isotropic and Anisotropic Raman Spectra of the v3 Mode of the CH3F/CD3F System
Authors: Schiel D. , Richter W. , Döge G.
Published: February 2015

It has been proved with the aid of CH3F/CD3F mixtures that the remarkably large non-coincidence effect in the Raman scattering spectrum of the v3 mode of liquid methyl fluoride is due to intermolecular vibrational coupling mediated mainly by transition dipole interaction. The amount of the effect and its temperature and mole fraction dependence are - at least qualitatively - in agreement with Logan's theoretical concept. The rather different behaviour of the isotopic species and the asymmetry and narrow width of the isotropic band, however, raise new questions which require further investigations.
Correlation of NQR and Chemical Bond Parameters
Authors: Weiss Alarich , Wigand Silvia
Published: February 2015

Nuclear quadrupole resonance is an effective spectroscopic method to investigate the charge density distribution in solids. The range of compounds which may be investigated is wide, reaching from a crystal lattice built up by an ordered arrangement of neutral molecules in the crystalline material to ionic crystals and to metallic solids.

First the correlations between NQR quantities and bond parameters which become apparent from the molecular orbital picture will be discussed, e.g. Hammett a, x-parameter, ionic character i, s-character, ionicity, electronegativity in their connection to NQR. Then, the correlations of NQR frequencies, respectively nuclear quadrupole coupling constants, with bond lengths and bond angles are considered.

Cross correlations, e.g. of NQR frequencies with bond distances, bond distances with vibrational frequencies, and vibrational frequencies with NQR frequencies are discussed as are pK A dependencies of NQR parameters. The connection of e
The Structure of Tetrachlorostannate Complexes with Ketones from 35Cl NQR Data
Authors: Feshin Valentin P. , Dolgushin Gennadii V. , Lazarev Igor M. , Voronkov Mikhail, G.
Published: February 2015

35Cl NQR spectra (77 K) of 1:1 and 2:1 RR'CO-SnCl 4 are recorded and discussed. These spectra change in the course of time. At low temperatures either octahedral or trigonal-bipyramidal complexes (depending on the ratio of components and the nature of ligands) are formed. Frequently these systems contain a mixture of steric isomers or a mixture of complexes having different coordination numbers of the tin atom. In the solid state some complexes show a transition from one to another configuration.
NQR Study of AlBr3 Complexes with Donor-Acceptor O-Al Bond
Authors: Ishihara Hideta , Nakashima Shouko , Yamada Koji , Okuda Tsutomu , Weiss Alarich
Published: February 2015

81Br and 27Al NQR were observed in AlBr 3 complexes with 4-XC6H4 NO,(X = H, CI, Br, I, CH3 , and C2H5), C6H5COBr, (C6H5)2CO, and (C2H5)2O. In the 4-XC6H4 NO2 complexes, the 27Al quadrupole coupling constants (QCC's) were well correlated with the Hammett er p 's of the para-substituents, i.e., electron-withdrawing groups caused reduction of the charge density of O-Al bonds which resulted in large 27Al QCC's and vice versa. The temperature dependences of the 81Br NQR frequencies and quadrupolar spin-lattice relaxation times showed that the 4-C2H5C6H4NO2 and C6H5 COBr complexes undergo phase transitions at 154 K and around 200 K, respectively, and show hindered rotation of the AlBr3 groups at higher temperatures, and that the (C2H5) 2O complex reorients above ca. 120 K.
Multinuclear Quadrupole Resonance Studies of Biological Systems
Authors: Hiyama Yukio
Published: February 2015

We have employed multinuclear quadrupole resonance, using the field cycling technique, to study the structure of heterocyclic biomolecules. The electron density at nitrogen was investigated by the Townes-Dailey model of 14N NQR. Large substituent effects were evident especially on the n orbitals. Electron transfer through H-bonds also affects the 14 N quadrupole interaction. Deuterium quadrupole resonance at exchangeable sites was also utilized. Since the deuterium quadrupole correlation coefficient is sensitive to the geometry of H-bonds, the intermolecular distance of the pyrrole-pyridine complex could be determined. The field cycling technique is sensitive enough to detect 14 N ··· 14 N double transitions in parabanic acid thanks to the long spin-lattice relaxation time. However in many biological systems, such as hydrates, the technique is hardly applicable because of the short proton relaxation times. In such cases the solid state NMR technique was utilized. The 2H NMR spectrum of thymidine reveals interesting static and dynamical features of deuterium quadrupole interaction.
Temperature Dependence Studies of 35Cl NQR Frequencies in Magnesium and Nickel Hexachlorotellurate(IV) Hexahydrates and Nickel Hexachloroiridate(IV) Hexahydrate
Authors: Sasane A. , Fukumitsu S. , Mori Y. , Nakamura D.
Published: February 2015

The 35Cl NQR frequencies in MgTeCl6 · 6H2O, NiTeCl6
· 6H2O, and NiIrCl6 · 6H2O have been determined at various temperatures. These compounds form rhombohedral crystals with the space group R3̄ ,showing a single resonance line. The 35Cl NQR frequencies of the Te(IV) complexes exhibit an unusual positive temperature coefficient. The deuterated analogs of the Te(IV) complexes show a small frequency shift at 77 K. These results are interpreted by the presene of O-H ··· CI type weak H-bonds. The resonance frequency of the Ir(IV) complex versus temperature curve shows a minimum and a maximum. This unusual temperature dependence is mainly explained by the same type of the H-bond as existing in the Te(IV) complexes. The π-bond formation between Ir and CI atoms is also partly responsible for the unusual temperature dependence.
Theoretical Study of the Indirect Quadrupole-Quadrupole Interactions in Metals and Alloys
Authors: Fazleyev N. G.
Published: February 2015

The indirect multipole interactions of nuclei and impurity paramagnetic ions in metals and alloys via conduction electrons are investigated by means of the dielectric function method. The Hamiltonian of the indirect quadrupole-quadrupole interaction of impurity paramagnetic ions and nuclei is constructed selfconsistently, taking into account the exchange interactions and correlations of the conduction electrons as well as the antishielding effects. It is shown that the energy of these indirect quadrupole interactions of the nuclei and the paramagnetic ions decreases with the distance as R ~ 3 , oscillating with a period which is determined by the wave vector on the Fermi surface and the distance R. The influence of these indirect quadrupole-quadrupole interactions on the width and shape of the NMR lines is studied.
Radio-Spectroscopic Studies of Magnetic Properties of High Temperature Superconductors
Authors: Lippmaa E. , Joon E. , Heinmaa I. , Miidel V. , Miller A. , Stern R.
Published: February 2015

We have performed 17O and 63Cu NMR measurements in YBa2Cu3O7-δ (δ ≈ 0.15) oriented powder samples at CuO2 plane sites Cu(2) and 0(2, 3) in the temperature range 10-300 K. The temperature dependent Knight shift K(T) and spin lattice relaxation rate T1
-1-(T) of O(2, 3) yield K2T1T = const in accordance with the presence of free carriers at plane oxygen sites. A sharp decrease of T1
-1 of Cu(2) below 120 K is associated with the opening of a gap in the spectrum of antiferromagnetic spin fluctuations of localized copper 3 d9 electrons. The comparison of different temperature dependences of spin densities at the Cu and O sites shows the presence of two nearly independent spin systems. A close similarity of YBa2Cu3O7-δ a with heavy fermion superconductors is discussed.
NQR and Zeeman Split NQR Investigations on Oriented YBa2Cu3O7-δ and Non-Oriented Bi-Ca-Sr-Cu-O Powder
Authors: Riesemeier H. , Kamphausen H. , Pattloch J. , Stadermann G. , Lüders K.
Published: February 2015

Powder samples of YBa2Cu3O7-δ a were oriented by mechanically vibrating the powder at 2.4 K in a magnetic field of 1.2 T. Zeeman split NQR spectra of 63,65 Cu were obtained for the two different Cu sites. The data confirm the orientations of the principal axis system: x ∥ c for the Cu (1) site and z ∥ c for the Cu (2) site. Asymmetry parameters were determined for the two Cu sites yielding η̄1 = 0.95 ±0.2 and η̄2 = 0.008 ± 0.002. At the Cu(l) site local variations of the symmetry of the EFG tensor were observed. For the Cu sites (CuO2 -layers) in the Bi2Ca2Sr2Cu3Oy phase a nearly axially symmetric EFG tensor was found.
Studies of 139La and 63/65Cu-NQR in La 2-xMxCuO4 (M = Ba, Sr)
Authors: Kumagai K. , Nakamura Y. , Watanabe I. , Nakajima H.
Published: February 2015

The nuclear quadrupole resonance of 139La and 63/65Cu in La2-x CMxCuO4 (M = Ba, Sr) is investigated for x up to unity. The shift of the resonance frequency of 139La-NQR for 0.01 < x <0.05 indicates an anomalous change of the quadrupole interactions at T*c, where the frustrated magnetic phase appears. The Cu-NQR reveals clear changes of T1
-1 and T2
-1 and also of the profile of the Cu-NQR spectra with increasing x beyond x = 0.3~0.4, suggesting a suppression of antiferromagnetic fluctuations by hole-doping, and also a change of the electronic state of the La-system around x = 0.3 ~0.4.
14N and 39K Nuclear Quadrupole Coupüng in KNO3
Authors: Bastow T. J. , Stuart S. N.
Published: February 2015

The nuclear quadrupole interaction tensors of 14N and 39K in potassium nitrate at room temperature have been determined from nuclear magnetic resonance (NMR) rotation studies of single crystals at 9.4 T. Values for the coupling constants and asymmetry parameters at 296 K are:

14N: e2 qQ/h = 751 kHz, η = 0.022;

39K: e2 qQ/h = 1326kHz, η = 0.171.

The temperature dependence, on approaching the order-disorder phase transition near 401 K, is linear.
On the Nature of the “Bleaching out” Process of the 35Cl NQR Signals in 1,2,3-Trichlorobenzene
Authors: Wigand Silvia , Weiden Norbert , Weiss Alarich
Published: February 2015

The 35Cl NQR frequencies, linewidths, and spin-lattice relaxation times T1(35Cl) of 1,2,3-trichlorotrideuterobenzene were measured at various temperatures. The deuterated compound shows the same bleaching out phenomenon as 1,2,3-trichlorobenzene. Single crystal 2H NMR measurements were carried out at 295 and 193 K. The nuclear quadrupole coupling constants at room temperature are in the range of 175.8 ≦ e2qQh-1 (2H)/kHz ≦ 179.5, and the asymmetry parameters η in the range of 0.060 ≦ η (2H) ≦ 0.073. As for the principal axes of the electric field gradient tensor, it was found that Φzz(2H) is parallel to the C - D bond, Φyy (2H) is perpendicular to the benzene ring plane and Φxx(2H) lies in the ring plane. The linewidths of the 2H NMR satellites are idependent of temperature. For the undeuterated compound, the temperature dependence of T1(1H) was also measured. The mechanism leading to the bleaching out of the 35Cl NQR signals is discussed.
Influence of Thermoactivated Molecular Motions on the 35Cl Quadrupole Relaxation
Authors: Kjuntsel I.A. , Mokeeva V. A. , Shaposhnikov I. G. , Soifer G. B.
Published: February 2015

The effect on the 35Cl quadrupole relaxation of modulations of the electric field gradient by thermally activated motions of nearby nonbonding symmetric and asymmetric atomic groups has been investigated. This way the activation energy of the motions has been determined and the fraction of the electric field gradient influenced by the motions has been estimated. This fraction can be taken as a measure of the intensity of nonbonding interactions in solids.
Antimony NQR and Nuclear Magnetic Relaxation in Hexaammonium Dodecafluorotrisulfatotetraantimonate (III), (NH4)6 Sb4(SO4)3F12
Authors: Chihara Hideaki , Nakamura Nobuo
Published: February 2015

Antimony nuclear quadrupole resonance frequencies in (NH4)6Sb4 (SO4)3 F12 crystals were measured as a function of temperature, and no evidence of phase transition was detected between 77 K and room temperature. However, the resonance frequencies do not follow the Bayer type exactly. Such an anomaly is attributed to the effect of rotation of ammonium ions which form hydrogen bonds of types N -H ···F and N -H ···O. In fact, the spin-lattice relaxation time of 1H and 19F has a minimum which is ascribed to the reorientation of NH+
4 with an activation energy of 7.14 kJ mol -1. The switch model for the electric field gradient at Sb nuclei was examined.
Optimal Zeeman-NQR Powder Lineshape Calculations for 3/2≦I≦7/2
Authors: Varty Theresa , Julian R. , Brown C. , Temme Francis P.
Published: February 2015

The powder lineshapes, associated with Zeeman-NQR Δ|m|= ±1 transitions for half-integer spin from 3/2 and 7/2 are derived using an optimized (θ, ϕ) sampling algorithm for the intensity response. The I = 3/2 system is examined over the full asymmetry range, whereas the I >3/2 lineshapes are calculated for η ≦0.35. The algorithm adopted is modelled on the concepts in the earlier NMR lineshape calculations of Alderman, Solum, and Grant.
Strong Quadrupole Interaction in ENDOR Spectroscopy
Authors: Böttcher R. , Heinhold D. , Windsch W.
Published: February 2015

If the nuclear quadrupole interaction ĤQ of the ligands exceeds the magnetic hyperfine ĤHF and nuclear Zeeman ĤNZ interaction (ĤQ ≫ ĤHF +ĤNZ), ENDOR spectra show the same behaviour as Zeeman field perturbed NQR spectra. The angular dependence of the transition frequencies and the transition probabilities of such ENDOR spectra for axial symmetry are calculated and applied to analyze the 35, 37Cl distant ENDOR spectra of gamma-irradiated NaClO3 single crystals.
Line Narrowing in Nitrogen-14 NQR by Non-Resonant Irradiation
Authors: Zhuang Y. L. , Marino R. A.
Published: February 2015

The effect of non-resonant irradiation on the linewidth of 14N NQR lines has been investigated in three cases with zero asymmetry parameter. The characteristic time of the free induction decay (T2 *) in Trimethylamine (TMA), Triethylenediamine (TED) and Hexamethylenetetramine (HMT) was studied at 77 K. Circularly polarized non-resonant irradiations of 11 kHz were used with intensities of up to 24 G with a geometrical arrangement following Ito and Hashi. The largest effect, a 100% increase in T2*, is measured in TMA. No observable effect occurs in HMT. An intermediate result occurs in TED, where the considerable narrowing caused by the non-resonant field serves to provide a greater resolution of the fine structure first reported by Colligiani and Ambrosetti. This fine structure, presumably dipolar in origin, is not itself affected by the non-resonant irradiation. The degree to which the theory of dressing fields can account for these results is discussed.
Microwave Spectra of Furazan. IV. Rotation Spectra of Vibrationally Excited States of Perdeuterated Furazan
Authors: Stiefvater Otto L.
Published: February 2015

The pure rotation spectra of molecules in 25 vibrationally excited states of perdeuterated furazan, C2D2N2O, have been studied by double resonance modulation (DRM) microwave spectroscopy. Twelve of these spectra have been correlated, -on the basis of relative intensity measurements under DRM -, with fundamental vibrations as previously established by IR spectroscopy. Rotational parameters for these 12 fundamental levels are reported, and the contributions to the effective rotational constants and to the inertia defect of the ground state of d2 -furazan have been determined for 10 modes of vibration.
Thermodynamische Betrachtungen von Schmelzdiagrammen einiger Systeme aus Methylchlorsilanen und Lutidinen
Authors: Hensen Karl , Dräbing Michael
Published: February 2015

A thermodynamic interpretation of the liquidus curves of some methyltrichloro-respectively dimethyldichlorosilane/lutidine-systems is given. Based on certain approximations it was possible to fit thermodynamic functions to the experimental results to obtain the excess datas of binary systems. A comparison between the models of Redlich-Kister, Wilson and the NRTL-formalism for the free excess enthalpy of binary mixtures is given.
Crystal Structure of 3Ni(N03)2
.16C6 H5NH2
Authors: Mahr Michael , Pabst Inge , Weil Konrad G.
Published: February 2015

The Compound 3Ni(NO3)2 -16C6H5NH2 was obtained by crystallization from solutions of Ni(NO3)2 • 6C6H5NH2 -2H2O in aniline. Its crystal structure was determined by single crystal X-ray diffraction. The crystals are triclinic, space group P1 with lattice constants a = 985.2 pm, ft = 1004.5 pm and c = 2514.3 pm, a = 96.34°, ß = 92.63° and y = 89.82°. The structure shows units of four aniline molecules and two slightly distorted nitrate ions in the coordination sphere of each nickel ion. These units are similar to contact ion pairs in concentrated ionic solutions.
The Transfer Matrix Grid Method for Quantum Partition Functions, Eigenvalues and Eigenfunctions
Authors: Prates Ramalho J. P. , Fernandes F. M. Silva
Published: February 2015

A method for the calculation of quantum partition functions, and bound eigenvalues and eigen-functions of the Hamiltonian operator is presented. The method is based on the discretization of the transfer matrix that relates the Feynman path integral to the conventional operator formulation of quantum mechanics. Its implementation is very simple, only requiring the diagonalization of the discretized transfer matrix. The method is applied to the harmonic oscillator and Morse potential. The results are in excellent agreement with the exact ones.
Ferroelektrische Cholesterin-Derivate
Authors: Vill V. , Thiem J.
Published: February 2015

The feature of liquid crystalline phases of p-alkoxybenzoyloxycholesterins was elucidated. In addition to blue, cholesteric and smectic A phases also monotropic, ferroelectric smectic C phases were detected. p-Alkoxybenzoic anhydrides obtained as side products in esterification reactions show highly ordered smectic phases which resemble those of the isosteric propanediones.
Molecular Motions and Phase Transitions in Solid CH3NH3PbX3 (X = C1, Br, I) as Studied by NMR and NQR
Authors: Xu Qiang , Eguchi Taro , Nakayama Hirokazu , Nakamura Nobuo , Kishita Michihiko
Published: February 2015

The temperature dependence of 35C1, 81Br, and 127I NQR frequencies and 1Hspin-lattice relaxation times (T1) for CH3NH3PbX3 (X = Cl, Br, I) was measured through the successive phase transitions in these solids. The isotropic reorientation of the CH3NH3 ions takes place in the higher-temperature phases (tetragonal [I4/mcm] and cubic) of the three salts (Ea= 11 kJ mol -1). T1's in the lowest-temperature phases (orthorhombic) indicate that the cations undergo correlated C3-reorientation in the chloride (Ea = 5.45 kJ mol -1)and in the iodide (Ea = 5.80 kJ mol -1, whereas correlated (Ea = 2.40 kJ mol-1) and uncorrected (Ea = 7.50 kJ mol-1) C3- reorientations are excited in the bromide. It is also revealed that the rotational tunneling of the cations governs T1 at lowtemperature region in the orthorhombic phases of these salts
Anisotropie Rotation of Yt-Base in n-Propanol at – 20°C Studied by Frequency-Domain Fluorometry and Global Analysis
Authors: Gryczynski Ignacy , Paszyc S. , Wiczk Wieslaw M. , Laczko Gabor , Joshi, Nanda , Szmacinski Henryk , Cherek Henryk
Published: February 2015

The frequency response of the polarized emission of Yt-base in n-propanol at -20°C was measured. Excitation wavelengths of 346, 312 and 285 nm were used for which the fundamental anisotropics were 0.32, 0.19 and 0.04, respectively. Additional data were obtained using CCl4 to decrease the mean decay time from 10 ns to 0.7 ns. These nine sets of data were analyzed globally to recover the anisotropy decay law. Two correlation times, of about 146 ps and 502 ps, were needed for a good fit
Notizen: The Preparation and Purification of Perhydrocoronene for Use as a Spectroscopic Matrix
Authors: Fetzer John C. , Biggs W. R. , Zander Maximilian
Published: February 2015

Perhydrocoronene has recently been studied as a matrix in low and high temperature luminescence spectroscopy of aromatic compounds. Perhydrocoronene has been found to be a by-product formed during the catalytic hydrocracking of a petroleum feedstock. The isolation and purification of spectroscopy grade perhydrocoronene is described in detail
Unbounded Perturbations of Boson Equilibrium States in Fock Space
Authors: Honegger Reinhard
Published: February 2015

Based on the linear coupling term in the non-relativistic quantum theory of matter-photon interactions, the coupling of a finite dimensional quantum system (finitely many finite-level atoms) with the boson gas (radiation field) in thermal equilibrium by means of perturbation theoretical methods is calculated. For the perturbation term of the Dyson expansion the unbounded interaction operator is taken. By a detailed analysis of the perturbation integrals and series, it is possible to derive the trace-class property of e-ßH , where H is the corresponding hamiltonian of the interacting systems and ß the inverse temperature
Steady-State and Flash Photolysis Investigations of 1 H-Indene-l,3(2H)-Dione Derivatives
Authors: Quint R. , Grabner G. , Quint R. M. , Getoff N. , Minchev St.
Published: February 2015

Pyrophthalone (PP, 2-(2-pyridinyl)-l H-indene-l,3(2H)-dione) and quinophthalone (QP, 2-(2-quinolinyl)- l H-indene-1,3(2 H)-dione) were investigated in various solvents with respect to their photostability. It was found that PP and QP in ethanol as well as QP in cyclohexane are rather stable under steady-state conditions using UV light (λ = 253.7 nm). Conventional as well as laser flash photolysis of airfree aqueous alkaline solutions (pH 12) lead to the formation of different radicals and solvated electrons (eaq). Some reaction rates were determined and probable reaction mechanisms were postulated
A Simple Rule regarding the Chemical Reactivity of S. T Isomer Pairs of kata-annellated Bejizenoid Hydrocarbons
Authors: Zander M.
Published: February 2015

For S, T isomer pairs of kata-annellated benzenoid hydrocarbons the inequality NS
min > NT
min holds, where NS
min and NT
min denote the lowest PMO localization energy of the S and T isomer, respectively. This empirical rule indicates that for a given S, T pair normally the S isomer will be the less reactive one
On the Spectra of Turbulent Velocity Field in a Stably Stratified Flow
Authors: Chakraborty A. K. , Vembe B. E. , Mazumdar H. P.
Published: February 2015

This paper describes a method to solve the spectral equation for the balance of turbulent kinetic energy in a stably stratified turbulent shear flow. The cospectra of vertical momentum and heat flux arc modelled with the aid of a basic eddy-viscosity (or turbulent exchange coefficient) function. For the term representing the inertial transfer of turbulent kinetic energy, Pao's [Phys. Fluids 8 (1965)] form is assumed. Analytical expressions for the three-dimensional kinetic energy spectrum as well as the cospectra of momentum and heat flux are obtained over the range of wave numbers k≥kb, which includes the inertial subrange kb≪k≪ks and the viscous subrange k>ks (kb and ks are the buoyancy and Kolmogorov wavenumbers, respectively). The two one-dimensional spectra, e.g., the kinetic energy spectra of the horizontal and vertical components of turbulence are derived from the three-dimensional kinetic energy spectrum. These one-dimensional spectra are compared with the measured data of Gargett et al. [J. Fluid Mech. 144 (1984)] for the case I ( = ks/kb) = 630. Finally, we compute the basic eddy-viscosity function and discuss its behavio
Equilibrium States and Phase Transitions of some FCC-Multi-Lattice Systems
Authors: Volkert H.-J. , Rieckers A.
Published: February 2015

The general formalism which connects quantum statistical and thermodynamical phase structures, developed previously, is applied here to a class of FCC-multi-lattice systems with four sublattices. A careful treatment of the symmetries gives insights into the origins of the rich phase structure. Arguments for the existence of the limiting Gibbs states are provided. A microscopic foundation of the Landau scenario for phase transitions, which predicts the active directions and the order parameters, is formulated for the considered models.
Rotation-Torsion Interaction in the Ground State Microwave Spectrum of Trans-gauche Ethylnitrite
Authors: Keussen Ch. , Dreizler H.
Published: February 2015

We investigated a small rotation-torsion interaction in the microwave spectrum of trans-gauche ethylnitrite, CH3CH2ONO. We found the difference between the two lowest energy levels of the torsion around the C-O bond axis to be 24.8(8) kHz. The high resolution of microwave Fourier transform (MWFT) spectroscopy was necessary to measure the resulting small splittings.
Radiation Induced Oxidation of Methanol
Authors: Jung Hak-Jin , Getoff Nikola
Published: February 2015

The radiolysis of methanol in the presence of air as well as of pure oxygen (1 to 5atm) was investigated, the yields of the major products: carboxylic acids (by far predominantly formic acid), oxalic acid, formaldehyde and glycolaldehyde were determined as a function of the absorbed dose. In addition small amounts (G≤0.05) of glyoxal, glyoxalic acid and glycolic acid were also detected. Based on the results a possible reaction mechanism is presented.
Viscosity Coefficients of a Nematic Mixture: Statistical Theory Approach
Authors: Terentjev E. M. , Osipov M. A.
Published: February 2015

A statistical theory of the rotational diffusion of a molecule in a two-component anisotropic mixture is developed, based on the Fokker-Planck approximation for the one-particle orientational distribution function. The friction constant of the molecular rotation is determined from the threeparticle correlation function, which takes into account interactions A-A, A-B, B-A and B-B between two sorts of molecules. The Leslie coefficients obtained possess a complicated dependence on mixture concentration together with a dependence on temperature and the molecular parameters of the components. In particular, the rotational viscosity coefficient γj is proportional to a polynomial of third-order in concentrations cA and cB with coefficients proportional to exp{JAca + JBcB} √(JACA + JB bcB )
Neutron and X-ray Scattering on Liquid Eutectic Ge-Te, Sn-Te and Pb-Te Alloys
Authors: Neumann Hartmut , Hoyer Walter , Wobst Manfred
Published: February 2015

From neutron and X-ray diffraction investigations on liquid Ge15Te85, Sn16Te84 and Pb14.5Te85.5 alloys the coordination numbers and nearest neighbour distances of these systems are obtained. The partial structure factors and partial pair correlations reveal that the short-range order of the eutectic Ge -Te melt differs from that of the eutectic Sn-Te and Pb-Te melts
Rotational Spectrum of Aminoborane: Centrifugal Distortion Constants and Boron and Nitrogen Hyperfine Structure
Authors: Vormann Kirsten , Dreizler Helmut , Doose Jens , Guarnieri Antonio
Published: February 2015

The boron and nitrogen hyperfine structure in the rotational spectra of two aminoborane isotopomers, 11 BH2NH2 and 10BH2NH2, has been investigated and the quadrupole coupling constants of boron 10B, 11B and nitrogen 14N have been determined. We get the following results for the nuclear quadrupole coupling constants: χaa(11B) = -1.684 (14) MHz, χbb(11B) = -2.212 (11) MHz, χcc(11B) = 3.896(11) MHz, χaa(10B) = -3.481 (11) MHz, χbb(10B) = -4.623 (14) MHz, χCC(10B) = 8.104 (14) MHz and xaa(14N) = 0.095 (9) MHz, χbb(14N) = 2.091 (8) MHz, χcf4 (14N)=-2.186 (8) MHz. These nitrogen quadrupole coupling constants are those of the 11BH2 NH2 isotopomer. Additionally we were able to determine two out of the three spin rotation coupling constants caa, cbb, and ccc of boron, caa(11 B = 55.2 (26) kHz, cbb(11B) = 6.62 (36) kHz, caa (10B) = 15.26 (69) kHz and cbb(10B) = 4.94 (70) kHz. The spin rotation coupling constants ccc had to be fixed to zero in both cases. Furthermore we measured the rotational spectra in the mm-wave region to determine all quartic and several sextic centrifugal distortion constants according to Watson's A and S reduction
Tetraalkylammonium Tetrachlorothallates (III); X-Ray, 35Cl-NQR, and 1H-NMR Studies
Authors: Lenck Marco , Dou Shi-qi , Weiss Alarich
Published: February 2015

The crystal structure of (CH3)4NTlCl4 and (C2H5)4NTlCl4 was determined at room temperature by single crystal technique. (CH3)4NTlCl4: D2h
17-Cmmm; Z = 2; a = 913.2pm, b = 894.6 pm, c = 752.5 pm; (C2H5)4NTlCl4: C6v
4-P63mc; Z = 2; a = 827.9 pm, c = 1329.8 pm. (C2H5)4NTlCl4 is isomorphous with (C2H5)4NInCl4. The compounds undergoe a phase transition at 239 K and 222 K, respectively. For both compounds no35 Cl NQR signal was observable in the high temperature phase I due to the dynamics of the anion. The 35 Cl NQR was studied in the low temperature phase II of both compounds as a function of temperature. (CH3)4NTlCl4 shows a two line, (C2H5)4NTlCl4 a four line spectrum. The possible phase II structures and the dynamics of the cation, studied by 1H-NMR, are discussed
Absorptions- and Electronic Raman Spectra of Chloro- Bromo-Osmate (IV), [OsClnBr6-nJ 2-, n=0-6
Authors: Irmer K. , Preetz W.
Published: February 2015

The electronic absorption spectra of the solid tetrabutylammonium salts of [OsClnBr6-n ]2-, n = 0-6, including the stereoisomers for n = 2, 3, 4, are measured at 10 K. The weak intraconfigurational excitations within the t2g
4, manifold of Os(lV) are split by spin orbit coupling and lowered symmetry into multiplets, observed in the NIR regions 2600-3100, 4800-5400, 10 500-11 400 and 16 000 17 200 cm-1. The 0-0-transitions are deduced from vibrational fine structure and they are confirmed by electronic Raman bands with the same frequencies
Unusual Temperature Dependence of 35Cl NQR Spin-Lattice Relaxation Time in [(CH3)4N]2[MCl6] (M = Pb, Sn, Te)
Authors: Furukawa Yoshihiro , Baba Yoshihisa , Gima Shin-ei , Kaga Makoto , Asaji Tetsuo , Ikeda Ryuichi , Nakamura Daiyu
Published: February 2015

The temperature dependence of the spin-lattice relaxation time (T1H) of 1H NMR measured in tetramethylammonium hexachloroplumbate(IV), (Me4N)2[PbCl6], showed a deep and a shallow minimum near 190 and 115 K, respectively. Since the presence of two kinds of crystallographically nonequivalent cations in the room-temperature Fd 3c unit cell has been reported, the deep T1H minimum was assigned to the overall reorientation of three quarters of the Me4N+ ions and the shallow minimum to that of the remaining cations. Two different temperature dependences of the chlorine NQR spin-lattice relaxation time (T1Q), attributable to a modulated electric-field-gradient by the protonic motion, were observed in (Me4N)2[MCl6] (M = Pb, Sn, Te). One is found in the Pb complex whose T1Q stems from the cationic motion responsible for the deep T1H minimum, and the other one is determined by the cationic motion giving the shallow T1H minimum. Although all room-temperature phases of these complexes are well described by the Fd 3c unit cell, the presence of different temperature dependences of T1Q suggests that the CH3 groups in the respective complexes take different orientations in the crystals
Solutions of Sodium in Liquid Ammonia as Described by a Hard Sphere Charge-Dipole Model in the Neutralizing Background
Authors: Golovko M. F. , Protsykevych L A.
Published: February 2015

The analytic solution of the mean spherical approximation obtained by us previously for the ion-dipole system in a neutralizing background is applied to study the structural, thermodynamic and dielectric properties of sodium-ammonia solutions. It is shown that the structure of ammonia is closepacked and changes little with ion concentration. The shape of the ion-ion distribution function changes from solvation behaviour with Debye-like asymptotics at low ion concentration to density ordering in the metalic region.
A Configurational Contribution to the Heat Capacity of Gaseous(HDO)2
Authors: Slanina Zdenek , Kalinichev Andrey G.
Published: February 2015

(HDO)2 can form two isomeric species, HOD.OHD and DOH.OHD. The species are studied in terms of the Bopp-Jancsö-Heinzinger potential. The deuterium-bonded structure is stabilized in zero-point vibrational energy by about 0.77 kJ mol-1 over the hydrogen-bonded one. In gas-phase the exactly equal stability of both structures would however be reached at a temperature of 638 K. The thermodynamic functions of HOD.OHD and DOH.OHD are different and, moreover, they essentially differ from the (overall) functions belonging to the equilibrium mixture of both structures (which is understood as one pseudospecies). For the heat capacity at constant pressure it is shown that a maximum of the difference between the pseudospecies' overall value and the HOD.OHD value appears at a temperature of about 39 K, amounting to some 4.6 J K-1mol-1
Spectroscopic Investigations of Intermolecular Interactions between Different Parts of Molecules
Authors: Luck W. A. P. , Peil S.
Published: February 2015

With the low temperature matrix techique we have observed different isolated IR OH vibration bands caused by van der Waals forces of single atom groups of the matrix molecules. With a series of different perhalogenated matrix molecules these different OH band frequency shifts ΔvOH can be correlated to OH interactions with C-F, C-Cl, C-Br resp. C-I groups. At higher temperatures T (solution spectra) the band positions of the different interactions become more similar because dv/d T increases with increasing interaction. This result clarifies why at room temperature band shoulders are observed and correlates these clearly to the different matrix bands and therefore to different interactions. These experiments demonstrate that intermolecular van der Waals potentials of asymmetric molecules cannot be approximated by one spheric potential but are angle dependent. This indicates the complexity of describe condensed media.
Interpretation of Vapor-Liquid Frequency Shift of CH stretching vibration of chloroform and Fluoroform
Authors: Tóth Katalin , Jancsó Gabor
Published: February 2015

The change in the frequency of the CH stretching vibration and in its anharmonicity constant, quadratic, cubic and quartic force constants and the equilibrium CH bond distance, on condensation, were investigated by performing model calculations for liquid chloroform and fluoroform. The interactions between the hydrogen atom and the CH oscillator, represented by a Morse potential, and the halogen atoms of its neighbor molecules were described by the sum of Lennard- Jones and Coulomb potential functions employed in molecular dynamics simulation. The calculations were carried out for different molecular arrangements in the liquid and have shown that mainly the size of the halogen atom, consequently the intermolecular distances, govern the direction of the CH vibrational frequency shift and of the change in the anharmonicity constant on the vapor-liquid transition. The pressure and temperature dependence of the CH stretching vibration was also studied for liquid chloroform. While the calculated pressure dependence is in good agreement with that observed, only the direction of the temperature dependence is in accordance with experimental observation.
Temperature Dependence of the Liquid-Vapor Isotopic Fractionation Factors in CD3H-CH4 and CD3F-CH3F Mixtures
Authors: Popowicz Anthony M. , Lub Ting-Hai , Bigeleisenc Jacob
Published: February 2015

The liquid-vapor isotope fractionation factors, LVIFF, α = CD3X/CH3X)1/(CD3X/CH3X)v, of CD3H-CH4 and CD3F CH3F mixtures have been measured from 102 160 K and 182 254 K, respectively. The results are in good agreement with previous vapor pressure ratios, VPIE, which cover the ranges 90 112 K and 132 211 K, respectively. Over the temperature ranges of the LVIFF measurements, ln α is negative for the CD3H-CH4 mixture and positive for the CD3F-CH3F mixture. There is significant curvature in a plot of T2 In α vs. T for the CD3H-CH4 mixture. The curvature is related to the densities of the liquid and vapor phases. It is shown that an expansion of the pair correlation function up to powers of the square of the densities of the liquid and vapor phases accounts for the T2 In α vs. T curvature and leads to In a equal to zero at the critical temperature. Correction of the LVIFF values of T2 In a for the density effect gives values for the contributions of translation, rotation and internal vibration in good agreement with previous cell model calculations. Similar treatment of the LVIFF data on the CD3F-CH3F mixture leads to the conclusion that the internal zero point energy effect on the differences in the heats of vaporization of CH3F and CD3F makes a small contribution to the overall difference in free energies of vaporization.
Monte Carlo Simulation of Magnesium Ion in 18.45 mol%Aqueous Ammonia Solution
Authors: Kheawsrikul Suchada , Hannongbua Supot V. , Rode Bernd M.
Published: February 2015

A Monte Carlo simulation has been performed for a magnesium ion in 18.45 mol% aqueous ammonia solution at 20 °C, using additive pairwise potential functions obtained from ab-initio calculations. The structural arrangement of the solvent molecules in the vicinity of the ion is discussed in terms of radial distribution functions and average molecular orientations. It was found that the first solvation shell of the ion consists of four water and three ammonia molecules, and the second shell of nine water and five ammonia molecules.
Solvent Isotope Effect on the Viscosity Coefficient B for Monovalent Ions in Water at 25 and 40°C
Authors: Ibuki K. , Nakahara M.
Published: February 2015

For heavy water solutions of LiCl, NaCl, KCl and CsCl at 25 and 40 C and KI at 25 °C the values of B(M + ) and B(X-) in the equation ]η/η0= 1 + A √c + [B(M + ) + B(X- )] c were determined under the conventional assumption B(K + ) = ß(Cl-). Here η0 is the viscosity of the solvent and c the molarity. The solvent isotope effect on the B values was found to be small. The B values for the medium-sized ions K + , Cs + , Br-, and I- were systematically more negative in heavy water than in light water. This is consistent with the idea that negative B values indicate the ability of the ion to break the structure of the water, the structure of heavy water being more developed than that of light water. For the tetraalkylammonium ions, Me4N + , Pr4N+ , and Bu4N + , on the other hand, the solvent isotope effect was small and random irrespective of the ion size. The temperature coefficients of B for the monatomic ions in heavy water were the same as for those in light water.
Conductance Studies on Aqueous Citric Acid
Authors: Apelblat Alexander , Barthel Josef
Published: February 2015

Conductance measurements of citric acid and neutral citrates (tri-lithium citrate, tri-sodium citrate and tri-potassium citrate) were performed in water at 278.15 to 308.15 K. The equilibrium constants for the primary and secondary steps of dissociation, Kx and K2, and the limiting conductances, λ0(H2Cit-), λ°(1/2 HCit2-), and λ0(1/3 Cit3-) are reported as a function of temperature. They are obtained by application of the Quint and Viallard conductance equation. The enthalpies of dissociation are estimated.
A Physico-Chemical Study of Concentrated Aqueous Solutions of Lithium Chloride
Authors: Tanaka Kazuko , Tamamushi Reita
Published: February 2015

The experimental values of density, viscosity, electric conductivity and diffusion coefficients of trace ions in aqueous solutions of lithium chloride in wide ranges of concentration and temperature are collected and discussed. The thermal expansivity and the activation energies of viscous flow, electric conductance and diffusion of trace ions show significant changes at a molality around 12 mol/kg, beyond which the hydration requirement is not satisfied
Effect of Pressure on the Self-Exchange Velocities in MD Simulations of Molten LiCl and LiBr Reflecting the Anomaly in the Conductivities
Authors: Okada Isao , Endoh Akira , Baluja Shipra
Published: February 2015

In molecular dynamics simulations of molten LiCl and LiBr at about 1000 K and various pressures the self-exchange velocity of unlike ion pairs divided by the molar volume increases with increasing pressure up to ca. 1000 MPa, reflecting the trend experimentally found for the electric conductivity up to 100 MPa. While the coordination of unlike ions is tetrahedral at low pressures, it is nearly octahedral at 2000 MPa.
Inelastic High-Energy Electron Spectrafrom Plane-Parallel Layer-Nonhomogeneous Surfaces
Authors: Afanas’ev V. P. , Naujoks D.
Published: February 2015

We consider inelastic backscattering of electrons with initial energy of tens and hundreds of keV by plane-parallel homogeneous and sandwiched targets. Basing on the invariance principle, we find expressions that describe the dynamics of the changes in the energy spectra of electrons reflected into a given solid angle that occur with increase of the thickness of films of different materials on substrates of finite and infinite thickness. We substantiate a procedure of linearizing the equations for the reflection function obtained by the method of invariant imbedding. We obtain an analytical solution of linearized equations in the form of a series in Legendre polynomials. A comparison with experimental data shows that the theory developed gives an adequate description of the process of electron backscattering.
The Range of the Wiener Index and Its Mean Isomer Degeneracy
Authors: Gutman I. , Šoltés L.
Published: February 2015

Sharp lower and upper bounds for the Wiener index (W) of a connected (n, m)-graph are reported; n = number of vertices, m = number of edges. The mean isomer degeneracy of W is estimated and is shown to unboundedly increase with increasing n. Thus the isomer-discriminating power of W is confirmed to be very low in the case of large molecules.
Dielectric Relaxation Spectroscopy of Electrolyte Solutions: ZnCl2 in N-Methyl-2-pyrrolidone
Authors: Brockmann  , Steffen A. , Stockhausen M.
Published: February 2015

The complex permittivity of the title solution system (c≤1.5 mol/1) was measured at frequencies ranging up to 72 GHz at 20 °C. Apart from the conductivity contribution there are two distinguishable relaxation regions, which are ascribed to the solvent (at higher frequencies) and to solvated ionic species (at lower frequencies).