bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Simulation System for Diffusive Oxidation of Silicon:One-Dimensional Analysis
Authors: Weinert Ulrich , Rank Ernst 
Published: February 2015

Abstract
Thermal oxidation of silicon is described as a three-component thermodynamic local process involving silicon, silicon oxide, and oxygen molecules. A simplified system of model equations is used to demonstrate the evoluton of the Si-SiO2 interface. For the one-dimensional case the equivalence with the model of Deal and Grove could be shown analytically. For that purpose effective interface coordinates have been introduced which establish the connection between the conventional concept of sharp interfaces and our "diffusive" interface, i.e., a transition region between pure silicon and pure silicon oxide.
The Molecular 0-Tensor, the Magnetic Susceptibility Anisotropy, and the Molecular Electric Quadrupole Moment Tensor of Monofluoroacetonitrile, a Rotational Zeeman Effect Study
Authors: Krause H. , Sutter D. H. 
Published: February 2015

Abstract
The rotational Zeeman effect of H2F12C12C14N was observed at fields up to 20 kG (2 Tesla). The observed vibronic ground state expectation values for the molecular ^-values, the magnetic susceptibility anisotropies and the molecular electric quadrupole moments, all referred to the molecular principal inertia axes system, are: gaa= -0.03572 (11), gbb= -0.03438 (7), gcc= -0.03988 (6). 2ξaa- ξbb - ξcc = - 14.58 (10) • 10-6 erg/(G2 mole), 2ξaa- ξbb - ξcc= 1.60 (11) • 10-6 erg/(G2 mole), Qaa= -9.13 (6) DÅ, Qbb = 4M (7) DÅ, and Qcc = 4.96 (9) DÅ, respectively. The latter are in close agreement with the results of a restricted Hartree Fock self consistent field calculation with a basis of TZVP quality, which was carried out at the partial restructure determined earlier. Therefore the RHF/TZVP-value for the second electronic moment perpendicular to the heavy atom plane, <0|Σ c2
c|0)RHF, was used as additional input to predict the molecular bulk susceptibility and the individual components of the magnetic susceptibility tensor
Chlorine NQR Spin-Lattice Relaxation and Electron Spin Dynamics in Paramagnetic [Co(H2O)6[PtCl6]
Authors: Mizuno Motohiro , Asaji Tetsuo , Tachikawa Atsushi , Nakamura Daiyu 
Published: February 2015

Abstract
Chlorine NQR spin-lattice relaxation times T1Q were determined for [Co(H2O)6][PtCl6] at 4.2 400 K. Above ca. 350 K, T1Q decreased rapidly showing the onset of a reorientation of [PtCl6]2-. The activation energy Ea of this reorientation was determined as 125 ± 15 kJ mol-1. With decreasing temperature, T1Q showed a maximum at ca. 250 K. Below ca. 200 K, T1Q. is governed by the magnetic dipolar interaction between chlorines and paramagnetic Co2+ ions and is inversely proportional to the electron spin correlation time τe of CO2+ . τe is shown to be determined by the electron spin-lattice relaxation time T1e and the temperature independent correlation time rs for the spin-exchange between neighbouring ions above and below ca. 50 K, respectively. The temperature dependence of T1e is explained by assuming the Orbach process with an energy gap A/k of 530 + 20 K as T1e = 5 x 10-14 exp(530/T)s. τs was estimated to be 0.9 x 10-10 s.
The temperature dependence of the ESR linewidth of Mn2+ impurities in single crystal was also measured, intending to study Co2+ spin dynamics. The limit of the ESR method is discussed by comparing the obtained results with those of the NQR method
Thermodynamic Study of Eu3+ /Eu2+ Redox Reaction in Aqueous Solutions at Elevated Temperatures and Pressures by Means of Cyclic Voltammetry
Authors: Bilal B. A. 
Published: February 2015

Abstract
The redox potential of the couple Eu3+/Eu2+ in aqueous NaCl, NaClO4 and Na2SO4 solutions of different ionic strength and various pH values has been determined by means of cyclic voltammetry up to 458 K and 1 kbar. In all cases reversible voltammograms were obtained. Compared to the redox potential in C1O4
- solutions of pH 2, no significant shift was observed in Cl-solutions of the same pH, whereas a drastic shift to more negative potentials in solutions of SO2-
4 and in Cl- solutions of higher pH (pH 3-5) was obtained. This indicates a negligible complexation of Eu3* by means of CP but a strong one by means of OH and SO2-
4 . An isothermal pressure increase up to 1 kbar led to a shift of only few mV more negative, indicating a small pressure dependence of the change of the partial molar volume (ΔVe1) accompanying the redox reaction, which results in this case only due to the different degrees of electrostriction. A more drastic shift of the redox potential (in the positive direction) results with increasing temperature. The isobaric temperature dependence of the redox potential is described by a two parameter equation which remains valid up to the saturation pressure at 458 K, due to the small pressure effect. ΔS and ΔH of the redox reaction has been determined
Fractionation of Oxygen Isotopes at the Faces of Smoky Quartz
Authors: Klemm A. , Banerjee A. , Hoernes S. 
Published: February 2015

Abstract
The 18O /16O ratio under the m- and r-faces of smoky quartz has been measured; the ratio of the growth velocities was Vm/Vr = 1/3. The obtained separation factor 1.00020 is compared with that obtained previously for amethyst (1.00043), where the ratio Vm/Vr was unity
Shock Waves produced by Impulsive Load: Equation of State Effects
Authors: Lifits S. A. , Anisimov S. I. , Meyer-ter-Vehn J. 
Published: February 2015

Abstract
A numerical study of the flow after impulsive load of a plane material surface is carried out. It is shown that the flow is asymptotically self-similar provided one can neglect the cold components in the equation of state. In this case the effective exponent s(t) = d l n (X s) / d ln(t), derived from the shock trajectory Xs (t) does not depend on the initial pressure pulse and approaches the exponent α of the self-similar problem for time t →∞. For equations of state containing a cold pressure term, s (t) is larger than α and changes non-monotonically with time. Some features of the flow related to the presence of cold components in pressure and internal energy are discussed.
Directions of the Electronic Absorption Transition Moments in ω-Substituted 4-Dimethylamino-trans-Styrenes
Authors: Kawski A. , Gryczynski Z. , Gryczynski I. , Kuśba J. 
Published: February 2015

a)
Absorption transition moment directions of the diphenylphosphinyl (2 a) and methylsulphonyl (3 a) Absorption transition moment directions of the diphenylphosphinyl (2 and methylsulphonyl

(3 a) co-substtuted in 4-dimethylamino-trans-styrenes were determined in stretched poylvinyl alcohol
(PVA) films based on measurements of the absorption anisotropics. It has been found that the
long-wave absorption spectrum consists of two bands corresponding to differently directed transition
moments. The transition moment of the intensive long-wave *La band is lies along the long axis
of these molecules whereas that of the short-wave band is oriented at (p = 38° for 2 a and q> = 35°
for 3 a relative to the transition moment direction of the 1La band-substtuted in 4-dimethylamino-trans-styrenes were determined in stretched poylvinyl alcohol (PVA) films based on measurements of the absorption anisotropics. It has been found that the long-wave absorption spectrum consists of two bands corresponding to differently directed transition moments. The transition moment of the intensive long-wave *La band is lies along the long axis of these molecules whereas that of the short-wave band is oriented at (p = 38° for 2 a and q> = 35° for 3 a relative to the transition moment direction of the 1La band
High Resolution FTIR Study of the ν8 Band and ab initio Calculation of the Harmonic and Anharmonic Force Field of Difluoromethanimine, CF2NH
Authors: Bürger Hans , Kuna Ralf , Pawelke Gottfried , Sommer Silvia , Thiel Walter 
Published: February 2015

Abstract
The ν8 band of CF2NH near 830 cm-1 has been measured with a resolution of 0.003 cm-1 and rotationally analyzed. The band is unperturbed, and its rovibrational parameters are given up to fourth order. Theoretical harmonic and anharmonic force constants have been calculated at the 6-31 G **SCF level, and all vibration-rotation interaction constants αi and anharmonicity constants xij are predicted. The theoretical results are compared with the available experimental data
Flüssigkristalline aromatische Cholesterin-Derivate
Authors: Vill V. , Thiem J. , Rollin P. 
Published: February 2015

Abstract
Liquid Crystalline Aromatic Cholesterol Derivates
A series of aromatic cholesteryl ethers, esters, phenylcarbonates and benzylcarbonates were prepared and their liquid crystalline properties studied. The occurence of ferroelectric phases as well as properties of cholesteric and blue phases alternate with the number of linking atomes between steroid and atomatic system
On the Problem of Bromide Control in a TI3+ -perturbed Belousov-Zhabotinsky Oscillator
Authors: Murányi Szilvia , Noszticzius Zoltán 
Published: February 2015

Abstract
It is shown that TI3+ as a bromide removing perturbant of the BZ oscillators is superior to Ag+ in several aspects. A most important advantage is that the upper limit of the actual Br- concentration can be calculated from the potential of a bromide selective electrode in the presence of the corrosive TI3+ ions. Experimental Potentiometrie traces of a bromide selective electrode in a TI3+ perturbed BZ system show that the Br- concentration stays much below its critical concentration during the oscillations. These observations suggest that free Br- is not the critical intermediate formed during reduction of Ce4+ and responsible for the negative feedback associated with the oscillations.
79Br Nuclear Quadrupole Relaxation in the High Temperature Modification of Niobium Pentabromide
Authors: Okubo Noriaki , Sekiya Harutaka , Ishikawa Chiaki , Abe Yoshihito 
Published: February 2015

Abstract
The spin-lattice relaxation time of 79Br NQR has been measured between 4.2 K and room temperature. The result is compared with that of 35Cl NQR in NbCl5. The origin of the relaxation is attributed to the quadrupolar interaction and the temperature dependence is explained by the Raman process. The Debye temperature is determined to be 94 K and the relaxation time is related with the NQR frequency through the covalency.
Molecular Motion in Solid Tetramethylammonium Tetrafluoroborate
Authors: Torre S. , Ferloni P. 
Published: February 2015

Abstract
Measurements of 11B and 1H NMR relaxation times, differential scanning calorimetry and thermomechanical analysis, carried out on polycrystalline (CH3)4 NBF4 from room temperature to about 100 K, have permitted to discuss the crystal dynamics of this salt and to analyze the nature of the phase transition occurring at ≈ 150 K. Moreover, by means of an evaluation of the 11B quadrupole coupling constant, information about the position of the F atoms has been obtained. An explanation of the NMR data in terms of an order-disorder phase transition involving the F- ions is given.
A Microscopic Theory of a Single Hydrogen Centre in a Magnesium Crystal
Authors: Gnirßt M. , Wahl F. 
Published: February 2015

Abstract
A microscopic theory of a single hydrogen center embedded in a magnesium crystal is presented. Starting with a many-particle Schrödinger equation, an adiabatic decoupling yields in an electronic system a protonic system and a host lattice system. The storage energy is defined to consist of an electronic part and lattice contributions. The electronic problem is treated with the help of a special energy difference procedure developed by Wahl et al. This procedure is applied in a higher approximation to calculate the electronic energy difference eigenvalue between a metal crystal with and without a hydrogen impurity. The lattice problem is treated in the classical harmonic approximation.
Peripheral Stochasticity in Tokamaks.The Martin-Taylor Revisited
Authors: Viana R. L. , Caldas I. L. 
Published: February 2015

Abstract
We analyse the effect of an Ergodic Magnetic Limiter on the magnetic field line dynamics in the edge of a large aspect-ratio Tokamak. We model the limiter action as an impulsive perturbation and use a peaked-current model for the Tokamak equilibrium field. The theoretical analysis is made through the use of invariant flux functions describing magnetic surfaces. Results are compared with a numerical mapping of the field lines
Polarisation in the Temperature Equilibration of Anisotropic Plasmas
Authors: Wolf U. , Schamel H. 
Published: February 2015

Abstract
The polarisation effect on the isotropisation of a magnetized bi-Maxwellian plasma is investigated in the weak coupling approximation. Based on the Rostoker collision operator, which reduces in the magnetic field free limit to the Balescu-Lenard operator, the equipartition frequency v is evaluated numerically for B→0 and analytically for B→∞, respectively. This frequency, depending nonlinearly on ε and B, describes the approach to thermodynamic equilibrium of the anisotropy parameter ε = T⊥/T‖ via dε/dt - (1 - ε) ν(ε, B). It is found that in both limits dynamical screening makes a negligible contribution to the relaxation process. For finite B a simplified, yet unexploited expression for ν(ε, B) is presented, which invokes three new functions
Comparison of Different Methods of Abel Inversion Using Computer Simulated and Experimental Side-On Data
Authors: Pretzier G. , Jäger H. , Neger T. , Philipp H. , Woisetschläger J. 
Published: February 2015

Abstract
A recently devised new method for numerical Abel inversion is compared with four other commonly used methods. One of them, the convolution method, is employed in computer tomography for reconstructing asymmetrical objects. It is investigated whether this method can be adapted for the case of radial symmetry. As a first approach the comparison is performed by computer simulation. Special attention is given to the propagation of errors according to their origin. The result is a recipe for minimizing errors and for choosing the optimal method for reconstruction. The second step is a comparison of experimentally obtained radial profiles with functions resulting from Abel inversion of measured side-on data. Thus it is shown that the concept developed by computer simulation can be applied in practice
Monte Carlo Simulations of Water under Supercritical Conditions. II. Convergence Characteristics and the System Size Effects
Authors: Kalinichev A. G. 
Published: February 2015

Abstract
The size dependence and convergence rates of thermodynamic averages during Monte Carlo simulations of supercritical water in a wide range of densities have been analysed and compared with simulations under normal conditions. It is shown that the fluctuations of internal energy (enthalpy) in NPT-ensemble Monte Carlo simulations of high-temperature water are strongly correlated with fluctuations of volume and the convergence of the thermodynamic averaging under such conditions depends on the frequency of volume-changing moves and may be considerably improved by increasing this frequency by a factor of 3 - 10 relative to generally accepted values
Probing the Electronic Structure of Y-Ba-Cu-O Superconductors by Copper NQR/NMR
Authors: Brinkmann D. 
Published: February 2015

abstract
The paper discusses some NQR/NMR studies performed on Y-Ba-Cu-O superconductors at the University of Zürich. It is shown how the resonance methods can yield information on electronic properties of quite different character. The review deals with: (1) the temperature and pressure dependence of Cu NQR frequencies in YBa2Cu4O8(1-2-4); (2) an NQR study of the properties of Ca substituted 1-2-4; (3) the temperature dependence of the Cu Knight shifts in 1-2-4; (4) the NMR of plane Cu2 in the paramagnetic state of YBa2Cu3O6 ; (5) the dependence on temperature, pressure and orientation of the Cu spin-lattice relaxation in 1-2-4.
Cesium Iodometallates(III), Cs3M2I9, with M = Rare Earth. A Structural Investigation by 127I NQR
Authors: Lenck Marco , Weiss Alarich 
Published: February 2015

Abstract
The 127NQR spectra of cesium enneaiododimetallates Cs3M2I9, M = Dy, Ho, Er, Yb, Y and Tb, Sm, Nd, Pr have been studied as a function of temperature. The compounds are characterized by X-ray powder diffraction, too. The first group of compounds, M = Dy • • • Y, belongs to the family of Cs3Cr2Cl9-type enneahalogenodimetallates (III). The crystal structure of the second group, M = Tb ...Pr , is less symmetric, as in the 127I NQR the presence of two crystallographically independent iodines shows up. Nuclear quadrupole coupling constants for the terminal and bridging halogens have been calculated from the NQR frequencies. The dependence of the NQR frequencies and of the crystal structure from the radius of the RE3⊕ -ion is discussed. The NQR spectra reveal phase transitions of the investigated enneaiododimetallates (III), for which Tlr also depends on r(RE3⊕). Positive temperature coefficients of the 127I have been found and the influence of π-bond character is considered.
NQR and X-ray Studies of [N(CH3)4]3M2X9 and (CH3NH3)3M2X9 (M = Sb,Bi; X = Cl,Br)
Authors: Ishihara Hideta , Watanabe Koichi , Iwata Ayako , Yamada Koji , Kinoshita Yoshihiro , Okuda Tsutomu , Krishnan V. G. , Dou Shi-qi , Weiss Alarich 
Published: February 2015

Abstract

35Cl, 81Br, 121Sb, and 209Bi NQR of the title compounds was observed. According to the results of the temperature dependences of NQR frequencies and the DTA measurements, phase transitions take place in [N(CH3)4]3Bi2Br9 (Ttr=183K), [N(CH3)4]3Bi2Cl9 (Ttr = 155K), and (CH3NH3)3Bi2Cl3 (Ttr = 200 and 249 K). 2D NMR spectra for partially deuterated (CH3ND3)3Bi,Br9 showed that the phase transitions in this compound are related to the motion of the methylammonium cations. Single-crystal X-ray work at room temperature shows that the space group for [N(CH3)4]3Sb2Cl9 is P63/mmc with a = 925.1 pm, c = 2173.4 pm, Z = 2. For (CH3NH3 ) 3Sb2Br9 the space group is P3ml with a = 818.8 pm, c = 992.7 pm, Z = 1; in both cases the cations show dynamical disorder. The Rietveld analysis of the powder X-ray diffraction for (CH3NH3)3Bi2Br9 reveals the space group P3ml with a = 821.0, c - 1000.4 pm, Z = 1 at room temperature; the compound is isomorphous with (CH3NH3 )3Sb2Br9 . The crystal symmetries of the low-temperature phases of (CH3NH3)3Bi2Br9 and [N(CH3)4]3Bi2Br9 were deduced from the results of the NQR spectroscopy
Coordination of Ortho-Chlorines in Copper (I) and Silver (I) 2,6-Di- and 2,4,6-Trichlorophenolates
Authors: Wulfsberg Gary , Jackson Debra , Ilsley William , Dou Shi-qi , Weiss Alarich , Gagliardi John 
Published: February 2015

Abstract
The crystal structure of (Ph3P)2AgOC6H2Cl3 (I) is reported along with the syntheses and 35Cl and 63Cu NQR spectra of I and several related silver (I) and copper (I) 2,6-di- and 2,4,6-trichlorophenolates containing phosphines, phosphites, and pyridine as co-ligands. I crystallizes in space group P21/cc with a= 16.692(4) Å, b= 17.942 (4) A, c = 12.857 (3) Å, β = 97.60 (1)°, F = 3816.68 Å3, and Z = 4. The final R (F) = 0.0475 and R (W) = 0.0396. Ag is coordinated in a trigonal planar geometry by the P atoms of the two triphenylphosphine ligands and the O atom of the chlorophenolate; Ag is then capped by one ortho-chlorine of the trichlorophenolate ligand at a distance of 3.160 (2) Å. In the 35Cl NQR spectrum of this compound the two ortho-chlorines of the trichlorophenolate ligand have a large frequency difference of 1.500 MHz, indicating that one ortho-chlorine is coordinated to the silver; 35Cl NQR spectra of related complexes are also presented and discussed. The 35Cl NQR frequency differences of coordinated and non-coordinated ortho-chlorines in metal chlorophenolates correlate well with the metal-chlorine distances but not with the metal-chlorine-carbon bond angles. A different correlation is found for the silver complexes of dichloroalkanes; possible reasons for this are discussed.
35Cl NQR Spectra of Organyl(chloroalkyl) Sulfides
Authors: Voronkov Mikhail G. , Dolgushin Gennadii V. , Feshin Valentin P. , Turchaninova Lyudmila P. , Korchevin Nikolai A. , Deryaghina Eleonora N. 
Published: February 2015

Abstract
The 35Cl NQR spectra of organyl(chloroalkyl) sulfides ClCH2S(CH2)nCH3, n = 0-11, Cl(CH2)mSR, m = 1 - 3 and alkyl(chloromethyl selenides ClCH2SeR (R = C2H5 , C3H7 ) have been obtained. In going from m = 1 to m = 2, the electron density on the CI atom in the series Cl(CH2)mYR increases when Y = S and decreases when Y = O.
Spatial Electron Density Distribution of Chlorine Atoms in Molecules of the Series Cl2C = CXX'
Authors: Feshin Valentin P. , Polygalova Gelena A. , Shchepin Vasilii V. , Sapozhnikov Yurii E. 
Published: February 2015

Abstract
The EFG asymmetry parameters at 35Cl nuclei have been measured for polycrystalline compounds of series Cl2C = CHX (X = OR, OCOR) and Cl2C = C(Cl)OCOR at 77 K. For the Cl trans-atoms in molecules Cl2C = CHX, the q values are equal or close to zero. For the Cl cis-atom of these compounds and for all Cl atoms of compounds Cl2C = C(Cl)OCOR, η ~ 6 - 9%. It was shown that the deviation from the axial symmetry of electron distribution of Cl atoms in these compounds is due to the influence not of the geminal, but of a vicinal atom or group directly through the field. The expected p, π -conjugation between the unshared electron pair of halogen and the Ti-electron system of double bond is absent in the molecules studied.
NQR and Crystal Structure of 4,5-Dichloroimidazole, C3H2N2Cl2
Authors: Dou Shi-Qi , Weiss Alarich 
Published: February 2015

Abstract
The two line 35Cl NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77≦ T/K ≦ 389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v ( 35Cl)= f(T). Also the temperature coefficients of the 35Cl NQR frequencies are "normal". At 77 K the 35Cl NQR frequencies are 37.409 MHz and 36.172 MHz and at 389 K 35.758 MHz and 34.565 MHz.
The compound crystallizes at room temperature with the tetragonal space group D4
4-P41212, Z = 8 molecules per unit cell; at 295 K : a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.
The ab initio Calculation of Nuclear Quadrupole Coupling Constants with Special Reference to 33S
Authors: Palmer Michael H. 
Published: February 2015

Abstract
The ab initio calculation of 33S nuclear quadrupole coupling constants (NQCC) for a range of S-containing compounds with S2, S4 and S6 bonding types is described. All of the calculations used a triple zeta valence + polarisation basis set (TZVP) of gaussian type orbitals; all of the molecules were studied at the TZVP equilibrium geometry. The electric field gradients (EFG) calculated were correlated with the experimental NQCC obtained by either microwave spectroscopy (MW), nuclear quadrupole resonance (NQR) or NMR relaxation methods; although the experimental data cover a wide diversity of chemical types over a long period of time, the slope of the relationship between the EFG (qii) and the NQCC (χii) yields a value for the 33S atomic quadrupole moment of - 0.064 barn, very close to recent calculations with a large atomic basis set, and to experimental data. The relationship between the EFG tensor components and the internal molecular structure features is discussed for a diverse series of molecules.
Phase Transitions in Bis(4-chlorophenyl)sulfone as Studied by 35Cl FT-NQR
Authors: Nakayama Hirokazu , Eguchi Taro , Kishita Michihiko 
Published: February 2015

Abstract
The temperature dependence of 35Cl NQR frequencies in bis(4-chlorophenyl)sulfone was measured in the temperature range of 4.2-297 K. Below 115 K four NQR lines due to four inequivalent chlorines exist in the commensurate phase, contrary to the single NQR line reported by Corbero et al. It follows that the commensurate-incommensurate transition is of the first-order, and the incommensurate-normal transition at 150 K is quasi-continuous. It is also suggested that the successive phase transitions are triggered by the small angle rotation of the molecules about their C2-axes.