bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semiempirical Studies of Core Electron Binding Energies Part 10. The SCC-MO Calculations on some Purines
Authors: Maksić Z. B. , Rupnik K. , Veseli A. 
Published: February 2015

Abstract
The solid state binding energies of 8-azaguanine, 8-azaxanthine, hypoxanthine and xanthine were calculated by using semiempirical self-consistent charge intramolecular electrostatic potentials expressed in the point-charge approximation. The results are essentially in good agree-ment with the experimental data giving in the same time a very simple and transparent inter-pretation of ESCA spectra which is close to the chemical intuition. Splitting of some unresolved N(1s) peaks is proposed and separate binding energies are attributed to particular nitrogen atoms. Since the point-charge model describes a number of molecular properties, it is concluded that formal atomic charges are meaningful within the adopted theoretical framework despite the fact that they can not be defined in a unique fashion. The relaxation energy and work functions of the studied molecular crystals are briefly discussed.
On the Photodecomposition of ClONO2 in the Middle Ultraviolet
Authors: Knauth H.-D. , Schindler R. N. 
Published: February 2015

Abstract
Photodecomposition of gaseous ClONO2 was investigated in a static system at wavelengths 265 nm and 313 nm. From the quantitative determination of the products O2 , N2O5, and ClO15NO2 formed, and from Φ(-ClONO2) it is concluded that the predominant primary step is ClONO2 + h v → Cl + NO3 (3).
On the Band Structure of Möbius Polymers
Authors: Polansky Oskar E. 
Published: February 2015

Abstract
The π-band structure of Möbius polymers (M) is compared with that of the open strip (F) and the cylindrical form (R) of the polymer considered. Under certain conditions, the bands of all these forms coincide. This is to be expected also for the σ-bands within the framework of extended Hückel theory.
Fluorescence of Trans-4-Cyano-4′-dimethylaminostilbene; No Evidence for a TICT State
Authors: Gruen Henry , Görner Helmut 
Published: February 2015

Abstract
The fluorescence properties of trans-4-cyano-4′-dimethylaminostilbene (trans-1) and a rigid analogue, in which the dimethylaminophenyl group is replaced by an indoline ring, trans-l-(4-cyanophenyl)-2-(5-[2,3-dihydro]N-methylindolyl)ethylene (trans-2) were studied in 20 solvents. The quantum yields of fluorescence (Φf) and of trans→cis photoisomerization (Φt→c) as well as the fluorescence maximum (ν̃f) and the bandwidth (⊿ν̃f) were examined. The activation energies (range: 3.5-7.8 kcal/mol) obtained from <2>f and <£t_c measurements are nearly the same for 1 and 2 in a given solvent. Φf , ν̃f and ⊿ν̃f as a function of solvent polarity and temperature show similar trends for 1 and 2. No dual emission was observed for either of the cyanostilbenes. These findings indicate that a twisted intramolecular charge transfer (TICT) state is not involved in the relaxation process of the first excited trans singlet state (1t*). The main deactivation pathway of 1t* competing with fluorescence is trans→cis photoisomerization by twisting about the C = C double bond in the first excited singlet state for both.
Spin-Lattice Relaxation Times of 1H in Aqueous Gadolinium Chloride Solutions
Authors: Köhnlein Doris , Lutz Otto , Ulmer Reiner 
Published: February 2015

Abstract
Spin-lattice relaxation times T1 of protons in aqueous solutions of gadolinium chloride have been measured at 2.11 T for a larger range of concentrations down to 0.035 millimolal. Very small amounts of GdCl3 decrease strongly T1 of the water protons.
Simulation of Amplitude Behaviour in the Ag+ Perturbed Excitable Belousov-Zhabotinsky Reaction by the Oregonator Model
Authors: Ruoff Peter 
Published: February 2015

Abstract
Potentiometrie measurements with platinum and silver electrodes of Ag+ induced oscillations in the oxygen-inhibited excitable Belousov-Zhabotinsky system are reported. Calculations based on the Oregonator model lead to the conclusion that the platinum electrode's potential is composed of two contributions, the Ce(III)/Ce(IV) redox couple which dominates at low Ag+ flow rates and the contribution of HBrO2 , HOBr and BrO2 which dominates at higher Ag+ addition rates.
Molecular Vibration Analysis of the Cage-Like Molecules β-P4S5, As4S5, P4S7, and AS2P2S7
Authors: Cyvin S. J. , Cyvin B. N. , Motz H. , Wibbelmann C. 
Published: February 2015

Abstract
The cage-like molecules β-P4S5 , As4 S5 , P4S7 and As2P2S7 are all supposed to have C2v -symmetry. A normal coordinate analysis was performed for those molecules, based on a very simple initial force field with three numerical parameters and valence coordinates including redundancies. A complete set of symmetry coordinates is given. The force field was refined by adjusting the symmetry force constants to fit exactly a set of observed frequencies. This was used to calculate the mean amplitudes of vibration and perpendicular amplitude correction coefficients. The standard thermodynamical values derived from spectroscopic data are also given. A set of frequencies was calculated for the so far unknown compound P4S6 .
Exact Solutions of Simple Nonlinear Difference Equation Systems that show Chaotic Behavior
Authors: Tsuchiya Taskashi , Szabo Attila , Saitô Nobuhiko 
Published: February 2015

Abstract
Exact solutions are given for May's simple difference equation and the broken linear model, both for extreme values of the parameters, and the relation between these two systems for the solvable cases is clarified. The invariant measure and the correlation function for each case are calculated using the exact solutions. The initial-value dependence of the behavior of the solutions, choatic or periodic, is completely determined. By using the exact solution, encounters of any two nonperiodic orbits can be precisely analyzed.
The Raman Spectra and Conformational Change of Simple Sodium Alkylsulfates and Sodium Alkyisulfonates in Aqueous Solution
Authors: Ikeda Teruki , Yoshida Tadayoshi , Okabayashi Hirofumi 
Published: February 2015

Abstract
In order to study the polar group effect upon conformations about CH2-CH2 single bonds, the Raman spectra of simple sodium alkylsulfates and sodium alkyisulfonates were measured. The ethylsulfate ion (CH3-CH2-O-SO3
-) in aqueous solution was found to take the trans form about the CH2 - O bond in 0.67-5.41 mol/1. For the n-propylsulfonate ion the Raman line due to the gauche form about the CH2 -CH2 bond was also observed, the trans form becoming predominant at higher concentrations. For the sulfate and sulfonate ions having butyl and hexyl chains, the concentration dependence of their molecular conformations was also investigated.
On the Role of Microcrystal Formation in Intermolecular Triplet-Triplet Energy Transfer in Rigid Glasses
Authors: Zander M. 
Published: February 2015

Abstract
The intermolecular triplet-triplet energy transfer system benzophenone (donor)/naphthalene (acceptor) was studied in various rigid glasses at 77 K. It is shown that energy transfer is much more efficient if the donor is present in the form of microcrystals than in the case where both donor and acceptor compound are in true solution.
A Carbon-13 Spin-Lattice Relaxation Studies of Simple Alkylsulfates and Alkylsulfonates in Aqueous Solution
Authors: Matsushita Kazuhiro , Terada Yukimasa , Yoshida Tadayoshi , Okabayashi Hirofumi 
Published: February 2015

Abstract
The C-13 spin-lattice relaxation times (T1) of a series of short-chain n-alkylsulfates and sulfonates in D2O solutions were measured at various concentrations. Even for ethylsulfate and n-propylsulfonate ions, inflections, due to association, in the reciprocal of the T1 vs. the inverse concentration plots were observed. The critical micelle concentrations (CMC's) of ethyl and butylsulfates are 3.0 and 2.5 mol/l, respectively, and those of propyl and butylsulfonate 2.3 and 1.9 mol/l, respectively. For the simple alkylsulfates, below the CMC a progressive decrease in T1 from the terminal methyl group towards the polar group was observed.
On the Reaction Mechanism of Scavenged Hydrocarbon Radiolysis
Authors: Földiák G. , Schüler R. H. 
Published: February 2015

Abstract
It is shown that in radiolysis not only the reaction of alkyl radicals with iodine, but also that of alkyl radicals with galvinoxyl is diffusion controlled. The activation energies of the reactions of alkyl radicals with iodine increase with molecular mass, following the Smoluchowski equation. In the gross reaction other reaction steps (e.g. polymerisation, combination) cover up this phenomenon.
Contribution of the Torsional Modes to the Equilibrium Distribution of Vibrational States and to the Specific Heat of a Chain Molecule
Authors: Costa J. A. Borges da , Scherer C. , Holz A. , Naghizadeh J. 
Published: February 2015

Abstract
The torsional modes of a chain molecule were studied recently under the assumption that it has a well defined spatial configuration at any time. Here we show how the averages over the possible configurations, for a distribution in thermal equilibrium, should be performed in the calculation of the thermodynamical properties. Our results show that the mean density of torsional states increases in the low frequency region with increasing temperature. The specific heat behaviour shows a considerable difference from the result obtained in the previous paper, where only the lowest energetic configuration was considered. The consequences of this result with respect to the configurational properties of polymer molecules near the θ temperature are discussed.
All-Temperature Partition Function from Variationally Optimized Canonical Density Matrix
Authors: Baltin R. 
Published: February 2015

Abstract
For the canonical density matrix C(r, r0,β) a variational ansatz C̄̄f = (1 - f̄) Ccl + f̄ Cgr is made where Ccl and Cgr are the classical and the ground state expressions which are exact in the high temperature (β → 0) and in the low-temperature limits (β → + ∞), respectively, and f̄ is a trial function subject to the restriction that f̄ → 0 for β → 0 and f̄ → 1 for β → ∞. With the approximation that f̄ be dependent only upon β, not upon spatial variables, the mean square error arising when Cf is inserted into the Bloch equation is made a minimum. The Euler equation for this variational problem is an ordinary second order differential equation for f̄=f(β) to be solved numerically. The method is tested for the exactly solvable case of the one dimensional harmonic oscillator.
109Ag NMR-Study of the Selective Solvation of the Ag+ Ion in Solvent Mixtures of Water and the Organic Solvents: Pyridine, Acetonitrile, and Dimethyl Sulfoxide
Authors: Mittermaier L. Guinand. K. L. Hobt. E. , Rößler E. , Schwenk A. , Schneider H. 
Published: February 2015

In mixtures of water (W) and one of the organic solvents pyridine, acetonitrile, and dimethyl sulfoxide (O), the silver ion forms the following solvate complexes: AgW2, AgWO, and Ag02. The chemical shift of 109Ag is strongly affected by the ligating solvent molecules, and replacing the ligand W by one of the three organic ligands yields a higher Larmor frequency. In solvent mixtures, only a single resonance line has been observed because of rapid chemical exchange. The measured chemical shifts in the range up to 400 ppm are mean values of the chemical shifts of the different solvate species in a given mixture, weighted with their relative concentrations.
The 109Ag chemical shifts were determined for 0.05 to 0.15 molal solutions of AgNO3, as functions of the mole fractions of the solvent components. Using a Gaussian least squares fitting routine, the individual chemical shifts of the Ag+ solvate complexes and the corresponding equilibrium constants were determined. This fit was successful for the whole mole fraction range of DMSO, while in the solvent systems with acetonitrile and with pyridine at higher concentrations of the organic component the chemical shift is influenced by more than two solvent molecules. In these cases equilibrium constants were calculated from chemical shift data for solutions of low mole fraction of acetonitrile and pyridine.
Quantenphysikalischer Zustandsraum im Kontinuum / Quantum physical state space in continua
Authors: Bopp Fritz 
Published: February 2015

Abstract
As previously shown, quantum physics for single pairs of creation and annihilation processes may be derived from first principles. Quantum physics at all can be therefore considered as an interplay of such elementary processes. This is easily possible if the number of pairs of processes is finite. Difficulties arise only for infinite numbers.
The difficulties are similar to those occurring in the derivation of the equation for an oscillating string from that for an oscillator chain. It is true that the spectra of both systems are not continuously connected. However, a weaker theorem is more important: The chain eigenvalue of each order converges to the string one of the same order for an infinitely growing number of oscillators of a certain kind. Therefore both systems are continuously connected in the sense of semiconvergency.
Exhausting the space continuum with a sequence of lattices equably becomming infinitely large and fine, the infinitely dimensional Hilbertspace is steadily connected with the finitely dimensional one in the sense of semiconvergency. It will be shown that the Hilbert spaces in the sequence of lattices yield the suitable tool for quantum physics as an interplay in the mentioned sense. This kind of Hilbert space, the so-called rational one, must be preferred in physics rather than the real one introduced by Hilbert, since all theories in physics are based on a finite number of data.
In particular, we formulate Dirac's equation in the rational Hilbert space. It is shown that, even in quantum physics, a theorem of classical physics remains true, according to which relativity results from certain principles formulating most obvious experiences. We obtain the Lorentz invariant Dirac equation mainly from a modification of Newtons definition II according to which p = Hυ/c2 (instead of p = m υ).
Proton NMR Studies and Lineshape Simulations of the Mesophases of Terephthalylidene -Bis -4 -n-propylaniline (TBPRA) — Evidence for Conformational Changes
Authors: Limmer St. , Findeisen M. 
Published: February 2015

Abstract
From comparison of simulated and experimental spectra in the nematic, smectic-A, and smectic-A phases of TBPrA it can be concluded that there are conformational changes of the molecule giving obviously rise to a continuous variation of the direction of the long molecular axis with respect to a frame of reference connected with a conformation of the molecule that was derived from the crystal conformation of TBBA.
Dissociative Ionization and Metastable Ions of Nitrobenzene and Nitrobenzene-d5
Authors: El-Kader F. H. Abd , Ahmed H. M. 
Published: February 2015

The kinetica energy released on the loss of CNO2 from nitrobenzene and deuterated nitrobenzene ions in the second field-free region shows that this loss does not occur as a single-step process.
The apparent heat of formation of the C6H+
5 ion is found to be 270.85 kcal mol-1, which is consistent with the ion having the cyclic structure.
Semiempirische Rechnungen zur Protonenaffinitat unverzweigter aliphatischer Amine / Semiempirical Calculations on the Proton Affinity of Unbranched Primary Aliphatic Amines
Authors: Raabe Gerhard , Fleischhauer Jörg 
Published: February 2015

The experimental gasphase proton affinities of some alkylamines are found to correlate with the Mulliken charges on the NH3-groups of the corresponding ammonium-cations as calculated by the semiempirical MINDO/3- and MNDO-method rather than with the electron density at the nitrogen-atom or the NH2-group of the corresponding Amines.
As can be seen from the charges of the NH2-groups of the amines, the alkyl-chains do not exhibit a general positive inductive effect. It is found that the amount of electron density transferred to an attacking proton increases with the length of the alkyl-chains. This effect is similar to the so-called inductomeric effect introduced by Ingold
Search for Streaks in Electron Diffraction Patterns of Strontium Titanate
Authors: Arenas German , Geiger Jürgen 
Published: February 2015

Abstract
Streaks were found in the electron diffraction diagrams of ion-etched single-crystalline SrTiO3 for beam incidence parallel to the [111] direction. The streaks correspond to intensity walls perpendicular to the [ζ00] directions in agreement with the theoretical prediction. The soft phonons seem not to contribute significantly to the streaks.
Influence of Internal Heavy Atoms on the Spectroscopic Properties of 9-Acetoxy-10-Phenylanthracene Derivatives
Authors: Heidt Janina R. 
Published: February 2015

Abstract
Absorption and fluorescence spectra, fluorescence quantum yields and decay times have been measured for new derivatives of 9-acetoxy-10-acetoxyhalogenophenylanthracene in dioxane. It is found that the strength of the absorption transition decreases with increases atomic number Z of the halogen substituent whereas the strength of the fluorescence transition is constant with the exception for the fluoro-substituted derivatives. The loss of mirror symmetry between the absorption and fluorescence spectra is more evident for the 10-(4-acetoxy-3'-halogenophenyl)anthracene derivatives than for the remaining compounds. The determined nonradiative electronic relaxation rate constant and "dark reactions" quantum yield increases with increasing Z value. These findings are explained on the basis of the spin-orbit coupling enlarged by the heavy substituent and through perturbation of the functional groups, which causes different changes of the molecular geometries in the S0 and S*1 states, respectively.
Photoluminescence of [22]Paracyclophane and p-Xylene in the Presence of Silver Ions
Authors: Zander M. 
Published: February 2015

Abstract
Phosphorescence spectra and phosphorescence lifetimes of [22]paracyclophane (I) and p-xylene have been measured in ethanol glass at 77 K in the presence of silver Perchlorate at various concentrations. From the results it is concluded that the ground state complex formed with AgClO4 is much more stable in the case of the cyclophane than with p-xylene. The results would indicate that under the conditions used [22]paracyclophane forms a 1:1 complex with AgClO4 with the silver ion being located within the cyclophane cage. Fluorescence quenching measurements in fluid solution at room temperature using ethyl bromide and AgClO4 as quenchers support this assumption.
Determination of Ultrasonic Absorption and Velocity and the Derived Thermodynamic Properties of Pure and Binary Molten Salts
Authors: Fuchs W. , Richter J. 
Published: February 2015

The absorption and velocity of ultrasonic waves in molten salts are studied with an improved pulse method, which allows an exact and immediate measurement of the runtime of the impulses and of the amplitude of the recorded signals.
The measurements are performed in the pure molten salts sodium nitrate, potassium nitrate, and silver nitrate as well as in the three binary mixtures of these salts in the temperature range between 430 K and 620 K at various compositions. All values are measured at 27.789 MHz, the resonance frequency of the quartz transducers being used.
From the ultrasonic velocity, together with the expansion coefficient and the specific heat capacity, the adiabatic compressibility, the adiabactic constant, and the Rao's constant have been calculated. From the ultrasonic absorption and velocity results the volume viscosity, which can be referred to the structural relaxation of the molecules in the fused salts investigated here.
P-Typ-verzögerte Fluoreszenz von 1-Naphthyl-9-carbazyl-methan
Authors: Zander Maximilian 
Published: February 2015

P-tvpe Delayed Fluorescence o f 1-Naphthyl-9-carbazyl-methane
At 77 K 1-naphthyl-9-carbazyl-methane adsorbed on filter paper shows predominantly delayed fluorescence o f the carbazole chromophore. The experimental findings are in agreement with the assumption that the carbazole chromophore after excitation by light absorption becomes first deactivated by intramolecular triplet-triplet energy transfer and then re-excited in a two-step mechanism including intermolecular naphthalene triplet-triplet annihilation and intramolecular singlet-singlet energy transfer from the naphthalene to the carbazole chromophore.
Zur Kinetik von Photofolge- und Photoparallelreaktionen
Authors: Ursin B. , Kleindienst H. 
Published: February 2015

The knowledge of the absorptivity of all components at the irradiation wavelength and the partial quantum yields is indispensable for the complete kinetic interpretation of a photoreaction.
For the mechanism

two iterative methods are recommended if the reaction products are isolable not at all or only in low yields.
The algorithms are particularly suitable for sensitive stilbenes and azastilbenes in oxidizing media.
Zur Kinetik von Photofolge- und Photoparallelreaktionen.
Authors: Ursin Bernd , Kleindienst Heinz 
Published: February 2015

For all types of the photoconsecutive reaction

with a (0) = a0 b(0) = c(0 ) = 0 an algorithm is recommended to calculate the absorptivity of B (inisolable) and the partial quantum yields φ1, φ2, φ3 and φ4.

The method depends on the so-called formal integration of the kinetic equations and the best fit of the unknowns to the absorbance-diagram and the kinetic constants.
A comparison with other optim ization methods for nonlinear equations is given.
A Dissipative Model of Plasma Equilibrium in Toroidal Systems
Authors: Wobig H. 
Published: February 2015

In order to describe a steady-state plasma equilibrium in tokamaks, stellarators or other non-axisymmetric configurations, the model of ideal MHD with isotropic plasma pressure is widely used:
0 = - ∇p + j x B .
The ideal MHD-model of a toroidal plasma equilibrium requires the existence of closed magnetic surfaces. Several numerical codes have been developed in the past to solve the three-dimensional equilibrium problem, but so far no existence theorem for a solution has been proved. Another difficulty is the formation of magnetic islands and field line ergodisation, which can only be described in terms of ideal MHD if the plasma pressure is constant in the ergodic region. In order to describe the formation of magnetic islands and ergodisation of surfaces properly, additional dissipative terms have to be incorporated to allow decoupling of the plasma and magnetic field. In a collisional plasma, viscosity and inelastic collisions introduce such dissipative processes. In the model used a friction term proportional to the velocity v of the plasma is included. Such a term originates from charge exchange interaction of the plasma with a neutral background. With these modifications, the equilibrium problem reduces to a set of quasilinear elliptic equations for the pressure, the electric potential and the magnetic field. The paper deals with an existence theorem based on the Fixed-Point method of Schauder. It can be shown that a self-consistent and unique equilibrium exists if the friction term is large and the plasma pressure is sufficiently low. The essential role of the dissipative terms is to remove the singularities of the ideal MHD model on rational magnetic surfaces. The problem has a strong similarity to Bénard cell convection, and consequently a similar behaviour such as bifurcation and exchange of stability is expected.
Analogues to a Julia Boundary Away from Analyticity
Authors: Kahlert Claus , Rössler Otto E. 
Published: February 2015

Dedicated to Prof. Ernst Bayer on the occasion of his 60th birthday
An analyticity-destroying term is introduced into the complex logistic map. Two types of selfsimilar basin boundaries are found, one a “coastline-type” direct analogue to Julia's, the other a locally smooth boundary that nevertheless is more complicated than the well-known “striated” fractal basin boundaries of Grebogi et al.