bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zur Korrelation von 0-0-Übergängen, Absorptions- und Fluoreszenzmaxima mit σ-Hammett-Konstanten / The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with theσ-Hammett constants.
Authors: Polansky O. E. , Fratev F. , Nikolov P. 
Published: February 2015

Abstract
The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with the σ-Hammett constants. The correlation of the 0-0-transitions and the maxima of absorption and fluorescence with the ff-Hammett constants lead to conclusions concerning the changes in the gap of the state involved and their curvatures due to substitution. The formalism can be applied also using other LFER parameters than σ-Hammett constants.
EPR Study of Hydration of Portland Cement
Authors: Lasič D. D. , Lahajnar G. , Blinc R. , Kocuvan I. 
Published: February 2015

Abstract
The microscopic nature of the solidification of cement was studied via a measurement of the time dependence of the fraction of freely rotating spin probes by electron paramagnetic resonance with and without added retardants.
The results seem to support the osmotic theory of cement hydration.
T2-Measurement on a Dipole-forbidden Transition of OCS
Authors: Bomsdorf H. , Dreizler H. 
Published: February 2015

Abstract
A double resonance pulse sequence experiment is described allowing the determination of the rotational relaxation time of certain dipole-forbidden transitions. Measurements on the pres­ sure dependence of To for the dipole-forbidden transition J = 0, M = 0 → J = 2, M = 0 of OCS have been performed using a superhet bridge type transient spectrometer. No significant difference of the results is found compared with measurements on the dipole-allowed transitions J = 0, M = 0 → J = 1, M = 0 and J = 1, M = 0, ± 1 → J = 2, M = 0, ± 1.
Dielektrische Relaxation starrer Dipolmoleküle in unpolaren Mischlösungsmitteln
Authors: Hufnagel F. , He Shi Ding 
Published: February 2015

Abstract
In isotropic mixtures of nonpolar aliphatic solvents the Debye relaxation time of rigid polar solutes is studied. It is represented by a characteristic libration frequency, an effective molecular diameter and the activation factor originating from the neighbourhood of the dipole molecule. The dependence on temperature of both relaxation time and viscosity yields a relation between them, so that a microscopic picture of the solvents cage can be given.
Centrifugal Distortion Effect in the Microwave Spectrum of 1,3-Dioxane-5-ol
Authors: Roman A. , Alonso J. L. , Mata F. 
Published: February 2015

Abstract
The microwave spectrum of 1,3-Dioxane-5-ol has been analysed in the frequency region 18.0-40.0 GHz and up to J = 30. The analysis gives refined rotational constants and values for the quartic centrifugal distortion parameters. Comparison is made between the results using two forms of the quartic Hamiltonian
EPR Study of the Molecular Ordering in the Liquid Crystal: HBT
Authors: Rao A. S. N. , Murty P. Narayana , Murty C. R. K. , Reddy T. Rs. 
Published: February 2015

Abstract
Ordering of molecules is observed in the nematic and smetic-B phases of the liquid crystal HBT below 74 °C. In the Sb phase there is a considerable decrease in the intensity without increase in the width of the EPR lines. This unusual behaviour is believed to be due to a order-disorder state with layers coupled by strong forces
Proton and Fluorine-Spin-Lattice Relaxation in Poly crystalline FeSiF6 • 6 H2O
Authors: Rager H. 
Published: February 2015

Abstract
The proton and fluorine nuclear spin-lattice relaxation has been measured in FeSiF6 • 6H2O in the temperature range 130 K ≦ T ≦ 420 K with standard pulse methods at 30 MHz. The relaxation times, T1(1H) and T1(19F), decrease with decreasing temperature according to the expression T1=a(I)exp(-Δ/T) (I = 1H, 19F). They show no significant dependence on the Larmor frequency. Thus, the unpaired Fe2+ electrons are mainly responsible for the proton and fluorine spin-lattice relaxation. The relaxation mechanism is described by an Orbach process. The ratio T1(19F)/T1(1H) is relatively constant over the whole temperature range investigated. This is explained by the strong H ... F bonds in FeSiF6 · 6H2O. The sharp increase of T1(1H) and T1(19F) at 224 K is attributed to the phase transition, which probably alters the crystal field at the Fe2+ centers
Host-Guest Energy Transfer Via Dipole-Dipole Interaction in Doped Fluorene Crystals
Authors: Port H. , Schneckenburger H. , Wolf H. C. 
Published: February 2015

Abstract
Fluorene mixed crystals have been investigated by sensitized fluorescence measurements in order to prove the importance of dipole-dipole interactions for singlet energy transfer. Fluorene: dibenzofuran (F:DBF) and fluorene:benz[f]indan (F:BI) are used. In these systems the optical transition dipole moments of host and guest molecules are perpendicular and parallel to one another, respectively. For these systems the host-guest energy transfer rate has been determined as a function of the guest concentration from the quantum ratio of guest and host emission (F:BI) and from fluorescence decay time measurements (F:DBF). The latter verified the particularly low transfer rate in F : DBF found in previous steady state investigations. The measured transfer rates at 1.3 K could be explained quantitatively taking into account the relative orientations of the host and guest transition dipoles and the oscillator strengths of the optical transitions. An increase of the transfer rate with increasing temperature between 1.3 K and 100 K in the system F: BI could be related to a change from energy transfer within perturbed states to excitonic band states of the fluorene crystal.
The Influence of Surface Structure on the Photoelectrochemistry of Polycrystalline n-TiO2-Films
Authors: Liditscheidl J. , Hartig K. J. , Getoff N. , Tauschnitz Ch. , Nauer G. 
Published: February 2015

Abstract
The relationship between the surface structure, film thickness and the photoelectrochemical behaviour (photocurrent, corrosion and stability) of n-Ti02-films produced by controlled thermal oxidation of titanium foils is carefully investigated. X-ray surveys, optical and scanning electron microscopical observations were performed to elucidate the surface structure. It is established that a special etching procedure of Ti-metal foils, followed by controlled oxidation at 600 to 700 °C for 10 to 30 min in the presence of sufficient oxygen results in n-Ti02 layers with a defined surface structure and high photoactivity. As charge transfer through the Schottky barrier is decisive for the photoefficiency, the formation kinetics of the oxide layer is the most influencing factor.
Splitting of Terms Beyond a D-Term in an Octahedral Ligand Field
Authors: Perumareddi J. R. 
Published: February 2015

Abstract
Although the procedure to calculate the ligand field energies of terms of a many d-electron configuration in cubic symmetry is known, we present a novel semiquantitative method for the splitting of d-electron terms in cubic symmetry. The method is based on quantitative calculations of one-electron orbitals of a given angular momentum. S p littin g o f T e r m s B e y o n d a D -T e r m in a n O c ta h e d r a l L ig a n d F ield
Interaction of the C = N Bond with the Cyclopropyl Ring
Authors: Al-Siaidi Shatha F. , Ibrahim Ibrahim T. , Shanshal  
Published: February 2015

Abstract
The conjugative interaction of the C=N bond with the cyclopropylring is studied using UV-spectrophotometric technique. The observed small bathochromic shift in the n-n* bands, relative to the spectra of similar compounds but with no cyclopropylring, is attributed to the interaction of the internal Walsh MO with the nonbonded MO of the Nitrogen atom (Zlint-n interaction) in the bisected conformation of the molecule. The observed bathochromic shifts of the 71-71* bands are explained in terms of the A-n interaction. The gas phase spectra of the azomethine derivatives show vibronic structuring of the band which when analyzed yeld wave number differences be­ tween the successive vibronic peaks, of the magnitude 720—860 cm-1. They are attributed to to the wave number differences between the successive C—N=C deformed ion levels in the excited state. I n te r a c tio n o f th e C = N B o n d w ith th e C y c lo p r o p y l R in g
Vibrations of a Cage-like Molecule, P4S3: Some Theoretical Aspects
Authors: Cyvin S. J. , Cyvin B. N. , Somer M. , Brockner W. 
Published: February 2015

Abstract
Two independent symmetry coordinate sets for P4S3 are developed, starting from the "method of fragments". A simple, approximate force field is expressed in terms of the two sets of symmetry coordinates, and the corresponding compliance matrices are given. The invariance of compliants is demonstrated. The potential energy distribution (PED) is discussed. An example is shown where the PED terms are clearly inadequate for the description of normal modes. A general warning against the interpretation of the PED in terms of such descriptions for cage-like structures seems to be warranted. V ib r a tio n s o f a C a g e -lik e M o le c u le , P 4S3 : S o m e T h e o r e tic a l A sp e c ts
Effect of an Electric Field on Electron Attachment to SF6 in Liquid Ethane and Propane
Authors: Bakale George , Schmidt Werner F. 
Published: February 2015

Abstract
The effect of an external electric field, E, on the electron attachment rate constant, ke, of SF6 was studied by a pulsed-conductivity technique in liquid ethane and propane at temperatures ranging from 133-176 K and 156-216 K, respectively. At constant temperature, ke was independent of E at fields less than Ec , the critical field above which the mobility becomes field-dependent, but at E> Ec, ke increased proportionally with De, the diffusion coefficient of the electron. Application of diffusion-controlled reaction theory to the ke - De dependence yielded an effective encounter radius of 14.5 Å for the e--SF6 reaction pair in both liquids. This encounter radius is discussed in terms of the electron-SF6 interaction energy and models of electron transport and attachment in low-mobility liquids.
Vibrational Spectra and Force Constants of Tetrasulfurtetranitride, S4N4 [1]
Authors: Steudel Ralf 
Published: February 2015

Abstract
Infrared and Raman spectra of solid and dissolved S4
14N4 and of solid S4
15N4 have been recorded and assigned in accordance with the molecular point group D2d. 22 of the 28 fundamental vibrations of both molecules have been identified and used to calculate force constants applying a modified Urey-Bradley force field with 9 independent constants. Good agreement between observed and calculated wavenumbers was obtained, and both Urey-Bradley and valence force constants are given. The results indicate that-S4N4 basically contains eight SN single bonds and two extremely weak SS bonds.
Microwave Rotational Spectra of 2-Bromofurane and 3-Bromofurane and Bromine Nuclear Quadrupole Coupling Tensors
Authors: Stolze M. , Hübner D. , Sutter D. H. 
Published: February 2015

Abstract
The vibronic ground state rotational spectra are reported for the 79Br-and 81Br-species of 2-Bromofurane and 3-Bromofurane. Both μa and μb-type spectra were observed. The small inertia defects confirm that the equilibrium configurations are planar. From the nuclear quadrupole coupling tensors it may be concluded that π-contributions to the C-Br bonds are smaller than in the Halobenzenes.
Dissociation Energy of the SbPb Moleculc from Mass Spectrometric High Temperature Studies
Authors: Zmbov K. F. , Neubert A. , Ihle H. R. 
Published: February 2015

Abstract
The observation of the gaseous BiPb molecule [1,2] suggests the existence of heteronuclear diatomic molecules of lead with the group V-b elements. The present paper reports on the identification of the SbPb(g) molecule and the determination of its dissociation energy by mass spectrometric Knudsen-effusion method.
Electronic Structure of Metallic Glasses from the Cu-Zr-and Cu-Ti-Systems as well as from some Transitionmetall-Metalloid- Systems by Means of X-Ray-Emission Spectroscopy
Authors: Falch Siegfried , Rainer-Harbach Georg , Schmückle Friedrich , Steeb Siegfried 
Published: February 2015

Abstract
Using an electron microprobe, the position and shape of the characteristic X-Ray emission lines from the elements Cu, Zr, Ti, Fe, Co, and Mn in metallic glasses of the systems Cu-Zr, Cu-Ti, Fe-B, Fe-P, Co-B, Co-P, Fe-Ge-P, Mn-Si-P, and Fe-Si-P were studied. In each case the lines were compared with those of either the crystalline element or the corresponding crystalline compound. Compared to electron spectroscopy methods such as XPS or UPS, the method used during this work has the advantage that the spectra obtained are specific for the corresponding element. The general trend of the results can be described in such a way that the energy of binding of the electrons to the corresponding atomic species is larger in the amorphous state than in the crystalline element, whereas the energy of binding of the electrons in the amorphous state is similar to that of the corresponding crystalline compound.
Generation of Gravitational Radiation in the Laboratory
Authors: Romero B. F. , Dehnen H. 
Published: February 2015

Abstract
The generation of gravitational radiation by coherent excitation of a long row of oscillators is investigated. In particular we have considered diatomic linear chains as an idealization of thin piezoelectric crystals. We find a highly focussed superradiant beam of gravitational radiation in direction of the row and a total radiation power larger than the incoherent superposition of the oscillator radiation by the factor λ̲/a (λ̲ wavelength*, a distance between neighbouring oscillators). In spite of these optimum conditions it seems to us that the attainable magnitude of the radiation power of approximately 10-22 erg/sec is not high enough for a successful laboratory experiment.
Synthesis and Mesomorphic Properties of 4,4'-Di-n-alkyl-bibicyclo[2.2.2]octanes
Authors: Reiffenrath V. , Schneider F. 
Published: February 2015

Abstract
The homologous series of di-alkyl-bibicyclo[2.2.2]octanes (methyl to octyl) was prepared. All homologues with the exception of the methyl compound show broad smectic phase ranges. For the pentyl homologue the smectic phase exists between 46 °C and 247 °C. X-ray investigations show a novel type of diffraction pattern.
Bestimmung der Beweglichkeit von Plutonium (VI) in wäßriger Lösung bei 298 K durch Leitfähigkeitsmessung / Determination of Ionic Mobilities of Plutonium (VI) in Aqueous Solutions at 298 K by Use of Conductivities
Authors: Arndt F. , Marx G. 
Published: February 2015

Abstract
In pure water the limiting ionic conductance of (1/2PUO2
2+)was found to be 59 cm2 Ω-1 mol-1 by use of conductivity measurements of PuO2(NO3)2 in diluted nitric acid and applying Kohlrausch's law. The values obtained were compared with those of other actinide-ions.
The X-ray Structure Factor of Liquid Glycerol
Authors: Soltwisch M. , Steffen B. 
Published: February 2015

The X-ray scattering intensity from highly viscous, liquid glycerol has been measured using MoKα-radiation (0.2 < qÅ < 10) between 250 K and 350 K. The corrected spectra were Fourier transformed to obtain the atomic radial distribution function.
For increasing temperatures one observes an increase of the X-ray intensity before the first structure maximum, and a broadening and a shift to lower-q-values of the main peak, while the peak height remains nearly constant.
The temperature dependent structure factors are compared with a model calculation, which in a simple way gives the correct compressibility limit. From the fits to the structure maximum the existence of orientational correlations is inferred.
Determination of Diffusion Parameters of Solved Molecules by Measuring the Relaxation Kinetics on the Picosecond Time Scale
Authors: Heumann E. 
Published: February 2015

Abstract
Picosecond probe beam spectroscopy is used to measure the nonstationary contribution to diffusion controlled excimer formation in dependence on concentration and solvent viscosity. Utilizing a kinetic model, the effective encounter radius and diffusion parameters of pyrene molecules in different solvents have been determined.
Carbon-13 NMR and Raman Scattering Studies of Potassium Propoxybenzoate and Potassium Butoxybenzoate. Conformational Change Due to Micellization
Authors: Okabayashi Hirofumi , Yoshida Tadayoshi , Terada Yukimasa , Ikeda Teruki , Matsushita Kazuhiro 
Published: February 2015

Abstract
Carbon-13 NMR chemical shifts and carbon-13 spin-lattice relaxation times of potassium propoxybenzoate and potassium butoxybenzoate in deuterium oxide solution were measured at various concentrations.
For the alkoxy group, the earbon-13 resonance peak of the O-CH2 segment is shifted rapidly up-field upon micellization, while the resonance peaks of other methylene groups are shifted downfield. This observation is ascribed to the conformational change of the alkoxy group on micellization.
In the monomolecular solution of potassium butoxybenzoate, the restricted state of the O-CH2 bond was estimated by carbon-13 spin-lattice relaxation time measurement. It was also found that micellization brings about a further restricted internal rotation about the O-CH2 bond.
The Microwave Spectrum of Imidazole; Complete Structure and the Electron Distribution from Nuclear Quadrupole Coupling Tensors and Dipole Moment Orientation
Authors: Christen Dines , Griffiths John H. , Sheridan John 
Published: February 2015

Spectra have been measured for eleven isotopic forms of imidazole, including single substitutions at each nucleus in turn. A complete rs-structure is obtained. The ring structure is:
N(1)-C(2) = 1.364 Å, C(2)-N(3) = 1.314 Å, N(3)-C(4) = 1.382 Å, C(4)-C(5) = 1.364 Å, C(5)-N(1) = 1.377 Å, ≮N(1)C(2)N(3) = 112.0°, ≮C(2)N(3)C(4) = 104.9°, ≮N(3)C(4)C(5) = 110.7°, ≮C(4)C(5)N(1) = 105.5° and ≮C(5)N(1)C(2) = 106.9°.
The N(1)-H(1) distance is 0.998 Å, while the C-H distances are all very close to 1.078 Å. The bonds N(1)-H(1) and C(2)-H(2) lie close to the external bisectors of the respective ring angles, but C(4)-H(4) and C(5)-H(5) are each displaced by several degrees from these bisectors towards N(3) and N(1) respectively. The electric dipole moment is established as 3.67 (5) D from Stark effects, directed almost parallel with the line joining the nitrogen nuclei. The properties and orientations of the two 14N-nuclear quadrupole tensors have been investigated, in particular through the spectra of the two mono-14N-imidazoles.
To the Mathematical Concept of Thermostatics To the Mathematical Concept of Thermostatics
Authors: Grauel A. 
Published: February 2015

Abstract
We discuss the integrated form of the laws of thermostatics by using Stokes theorem on manifolds. We give a new insight to the basic properties of thermostatics, in particular we show that only the second law is a necessary condition to identify the integrating factor with the temperature. Moreover we consider the thermodynamical field equations for discontinuous media and discuss the properties of thermostatics.
Semiempirische Rechnungen zum Einfluß des Lösungsmittels auf die Protonierungsenergie des Anilins, des Ammoniaks und einiger aliphatischer Amine
Authors: Fleischhauer Jörg , Raabe Gerhard 
Published: February 2015

Abstract
The MINDO/3- and the MNDO-method have been used to determine the site of protonation of Aniline in the gas phase. We used the results of our semiempirical calculations together with the electrostatic "Solvaton-Model" to study the influence of the solvent on the energetics of the protonation of some amines and the site of protonation in Aniline. Our results indicate that the "Solvaton-Model", although neglecting specific interactions between solvent and solute such as the formation of hydrogen bonds, describes the change of the energy of solvation during the protonation in a rather successful agreement with experimentel results.
Infrared Studies of Rotational and Vibrational Relaxation in Liquid Cyclohexane
Authors: Bien T. , Döge G. , Yarwood J. , Arnold K. E. 
Published: February 2015

Abstract
Molecular correlation functions have been determined for the infrared active vibrations ν16, ν29 , ν30 and ν31 of neat liquid cyclohexane at different temperatures. The results have been com-pared with calculated reorientational correlation functions.
Energy Transfer Among Like and Unlike Molecules in Solution VI. Effect of the Mediation of Donor Molecules Upon the Electronic Excitation Energy Transfer in Binary Systems
Authors: Kawski A. , Szmaciński H. 
Published: February 2015

Abstract
The effect of an interdonor energy transfer is investigated on the following donor-acceptor systems in thin rigid cellulose acetate films: anthracene and tetracene (I), 9-methylanthracene and 2-aminobenzophenone (II), 9,10-diphenylanthracene and 2-aminobenzophenone (III). The donor quantum yield and fluorescence anisotropy in systems I-III are in good agreement with theoretical predictions for a model of a multi-step excitation energy transfer process. In mixed two-component solutions the donor fluorescence anisotropy is higher than in single-component solutions, indicating an interdonor excitation transfer preceding the donor-acceptor transfer in these binary systems.
Topological Properties of Benzenoid Systems. IX *. On the Sextet Polynomial
Authors: Gutman Ivan 
Published: February 2015

Abstract
A number of mathematical relations for the sextet polynomial are derived. A graph has been introduced (the so called C-graph), representing those properties of a benzenoid system which are essential in the sextet theory of Clar. The main structural properties of the C-graph are deter-mined. The obtained results contribute towards a better understanding of the algebraic and combinatorial background of Clar's theory of the aromatic sextet.
A Highly Resolved Yibronic Spectra of Dioxido-p-terphenyl and Trioxido-p-quaterphenyl in n-Hexanc at 77 K
Authors: Kawski A. , Ligȩza M. 
Published: February 2015

Abstract
Highly resolved vibronic absorption and fluorescence spectra of dioxido-p-terphenyl and the fluorescence spec-trum of trioxido-p-quaterphenyl in n-hexane at 77 K were obtained. The analysis of the vibrational structure in the excited singlet Si and in the ground So state gives funda-mental frequencies in the ground state in good agreement with those from infrared (IR) and Raman spectra.
Microwave Spectrum of γ-Thiobutyrolactone
Authors: Alonso José L. , Lopez J. C. , Mata F. 
Published: February 2015

Abstract
The microwave spectrum of γ-thiobutyrolactone has been observed and measured in the vibra-tional ground state and in several excited states of the ring-bending and ring-twisting modes. From the value of the μc component of the dipole moment and inertial-defect considerations the ring skeleton was shown to be non-planar. The average intensity ratio for the rotational transitions between the ground and excited vibrational states indicates that the first excited state of the ring-bending and ring-twisting modes are ~ 120 cm-1 and ~ 250 cm-1 above the ground state respectively. These two out-of-plane ring vibrations are essentially independent and the ring-bending vibration is governed by a nearly harmonic potential energy function. The components of the dipole moment were determined by the Stark effect to be μa = 3.770 ± 0.001 D, μb = 1.818 ± 0.044 D and μc = 0.832 ± 0.018 D, leading to μtotal = 4.268 ± 0.023 D. The rigidity of the γ-thiobutyrolactone ring is discussed in relation to those of related molecules.