bluuebunny/crossref_metadata_2025 huggingface dataset:
The Electronic Structure of Crystalline Li21Si5. A Cluster Approach to a γ-Brass Structure
Authors: Ramirez Rafael , Nesper Reinhard , Schnering Hans Georg von , Böhm Michael C.
Published: February 2015

The electronic structure of crystalline Li21Si5 is investigated by semiempirical MO (molecular orbital) calculations of the INDO (intermediate neglect of differential overlap) type in the framework of a finite cluster approach. The complex solid-state ensemble with 416 atoms per unit cell is divided into 16 cluster units M26 that form the three-dimensional structure. These M26 clusters have two different chemical compositions and act as formal donor and acceptor fragments, namely D = (Li20Si6) and A = (Li22Si4), having the formal net charges q(D ) = - 4 and q(A) = + 4. The electronic structures of these finite building units are rationalized by the semiempirical MO model. The one-electron energies of (Li20Si6)4- and (Li22Si4)4+ are derived on the basis of fragment interactions between the site sets (tetrahedral, octahedral, cube-octahedral) that build up the different M26 units. The canonical MO’s are transformed by means of the Edmiston-Ruedenberg localization procedure in order to come to a clear representation of the chemical bond in the two clusters. In (Li20Si6)4- a coincidence of the classical valence rules and the existence of nonclassical many-center bonds is found. (Li22Si4)4+ on the other side violates the counting schemes because of an excess of 2 electrons (electron octets at Si). The model calculations show however that the octet rule is strictly fulfilled in the Si subspace. The Li centers allow for the formation of an additional bonding cage orbital due to in-phase interactions between the Li 2s AO’s. This MO is occupied by the two excess electrons which are left after filling the valence orbitals associated to Si. The formation of such a one-electron level is not considered in classical models. The Li-Si interaction in Li21Si5 is of covalent nature and is comparable to the metal-nonmetal bonds in other lithium silicides. The Li-Li contacts are nonbonding in the framework of the Hartree-Fock approximation. The observed solid-state structure of the binary phase can be explained by intercluster interactions between the different donor and acceptor fragments.
Notizen: Diffusion in the Liquid System Chloroform + Methyl Acetate
Authors: Haase R. , Engels W.
Published: February 2015

We present and discuss the results of measurements of the diffusion coefficient D and the activity coefficients as functions of the mole fraction x of one of the components in the liquid system chloroform + methyl acetate at 10 °C, 30 °C, and 50 °C. The function D(x) exhibits a pronounced maximum at each temperature, while the kinematic diffusion coefficient D*, considered as function of x, shows a flat minimum, its composition dependence being nearer to a linear relation than that of D(x).
The Rotational Zeeman Effect of Pyrazole and Imidazole
Authors: Stolze M. , Sutter D. H.
Published: February 2015

The rotational Zeeman effect of the most abundant isotopic species of pyrazole and of imidazole has been studied under Δ M= 0 and Δ M = ± 1 selection rules. With field close to 1.9 Tesla, the nuclear Zeeman effect uncouples the rotational angular momentum and the spins of the two nonequivalent 14N quadrupole nuclei. The observed g-tensor elements are gaa = - 0.07498(14), gbb = - 0.12531(13), and gcc = 0.06346(12) for pyrazole and gaa = - 0.09339(16), gbb = - 0.10444(14), and gcc= 0.06051(15) for imidazole. The values for the magnetic susceptibility anisotropies in units of 10-6 erg/(G2 mol) are 2Xaa - Xbb - Xcc = 39.53(24) and 2Xbb - Xcc - Xaa = 51.20(21) for pyrazole and 2xaa - Xbb - Xcc = 45.76(31) and 2Xbb - Xcc - Xaa = 42.19(41) for imidazole. (Given uncertainties are single standard deviations of the fit.)

The so-called nonlocal (π-ring current) contributions to the out of plane components of the susceptibility tensor Xcc
nonlocal, derived as differences between the observed susceptibilities and values calculated from additivity rules for local atom susceptibilities, are compared to those derived earlier for other aromatic five membered ring molecules.
Derivation of Theoretical Formulas for Resonance Integrals from Heisenberg Equation of Motion. III. Inclusion of Rydberg and/or Inner Atomic Orbitals in the Formalism of NDO-Method Valid for Transition Metal Compounds
Authors: Leszczyński Jerzy , Lipiński Józef
Published: February 2015

On the basis of the Heisenberg equation of motion and Linderberg-Seamans approximations the analytical formulas for one-electron, two-centre resonance integrals have been derived. The possibility of inclusion of Rydberg and/or inner orbitals to the basis set in the case of d-electron element compounds has been taken into consideration. An application of the derived formulas to the modification of semiempirical, NDO-type methods has been presented. The results of the test INDOL/R version calculations for H2O molecule and MnO4
- ion confirm the utility of the method.
The Divergence of the Viscosity of a Fluid of Hard Spheres as an Indicator for the Fluid-Solid Phase Transition
Authors: Koo Hyearn-Maw , Hess Siegfried
Published: February 2015

Solution of the Kirkwood-Smoluchowski equation for a hard sphere fluid yields an expression for the viscosity which shows a dramatic pretransitional increase and a divergence at a number density close to that one observed in computer simulations and in colloidal dispersions. The value for the transition density stems from a boundary condition at the surface of the hard sphere in the configurational relative pair-space and makes use of the density dependence of the pair-correlation function and of its derivative at the point of contact.
Canonical Transformations, Entropy and Quantization
Authors: Bruhn B.
Published: February 2015

This paper considers various aspects of the canonical coordinate transformations in a complex phase space. The main result is given by two theorems which describe two special families of mappings between integrable Hamiltonian systems. The generating function of these transformations is determined by the entropy and a second arbitrary function which we take to be the energy function. For simple integrable systems an algebraic treatment based on the group properties of the canonical transformations is given to calculate the eigenvalue spectrum of the energy.
Parameters of the Morse Potential from Second Virial Coefficients of Gases
Authors: Matsumoto Akira
Published: February 2015

An analytic expression for the second virial coefficient in case of the Morse potential is derived. The parameters of the Morse potential are determined for eighteen species comprising inert gases, diatomic and polyatomic molecules, and mixtures of gases using experimental second virial coefficients. The calculated second virial coefficients based on the obtained Morse potential agree well with the empirical second virial coefficients and their temperature dependence.
Schwingungsspektrum des Quecksilber-Hexaselenidohypodiphosphates Hg2P2Se6
Authors: Brockner Wolfgang , Pätzmann Ulrich
Published: February 2015

Mercury Hexaselenidohypodiphosphate Hg2P2Se6 has been prepared and its vibrational spectrum recorded. The observed frequencies of Hg2P2Se6 are assigned on the basis of P2Se6
4- units with C2h symmetry. DTA data have been determined and interpreted.
X-Ray Diffraction Study of Amorphous CeFe2H3 and GdFe2H3 Alloys Produced by Hydrogenation
Authors: Matsubara E. , Ohzora Y. , Waseda Y. , Aoki K. , Fukamichi K. , Masumoto T.
Published: February 2015

The structure of amorphous CeFe2H3 and GdFe2H3 alloys produced by hydrogenation is investigated and compared with that of amorphous CeFe2 and GdFe2 produced by high-rate DC sputtering. Distinct different structural features, characterized by an almost resolved first peak of the RDF of the former were found.
Raman-Spektren der Hexathiohypodiphosphate des NH4, Mg, Ca, Sr und Ba
Authors: Pätzmann Ulrich , Brockner Wolfgang
Published: February 2015

The title compounds have been prepared and their Raman spectra recorded. The observed frequencies of (NH4)4P2S6 and Mg2P2S6 are assigned on the basis of P2S6
4- units with D3d symmetry. The Raman spectra of the Calcium, Strontium and Barium compounds indicate symmetry splitting, therefore the P2S6
4- frequencies are assigned with C2h symmetry. This assignment is supported by the correlation D3d → C2h. It is concluded that Sr2P2S6 and Ba2P2S6 crystallize in the monoclinic modification II.
Rubidium Isotope Separation by Constant Current Electromigration in a Cation-exchange Membrane
Authors: Hosoe Morikazu , Oi Takao , Nagumo Tadashi , Kakihana Hidetake
Published: February 2015

Separation of rubidium isotopes (85Rb, 87Rb) by electromigration in a cation exchange membrane has successfully been carried out in a band operation manner at 25 °C. The migration velocity has been varied from 2.5 to 12.1 cm/h. There existed a wide non-isotope-fractionated zone between the 85Rb enriched zone at the front and the 85Rb depleted zone at the rear of the band. The single stage separation factor was about 1.0009 and was independent of the migration velocity, migration length and operation technique at a given temperature. The steepness of the 85Rb accumulation curves, increased with increasing migration velocity.
X-Ray Diffraction Studies on Alicyclic Saturated Discotic Liquid Crystals
Authors: Neuling H. W. , Stegemeyer H. , Praefcke K. , Kohne B.
Published: February 2015

The discotic liquid crystalline phase of a new class of disc-like molecules (hexa-O-alkanoylscyllo- inositoles) is studied by small angle X-ray scattering, DSC and optical observations. Comparison of these three methods allows the determination of the structural arrangement. X-ray film exposures of oriented samples clearly demonstrate the hexagonal columnar ordered type of mesophases. A simple model calculation shows that the alkyl chains of neighbouring columns interpenetrate each other to a small extent.
Empirical Quantitative Relationship between Molecular Structure and Phosphorescence Transition Energy of Polycyclic Aromatic Thiophenes
Authors: Zander Maximilian , Jacob Jürgen , Lee Milton L.
Published: February 2015

Empirical quantitative models have been studied that relate the phosphorescence transition energies of thiophene benzologs and corresponding aromatic hydrocarbon systems. Phosphorescence 0,0 bands, phosphorescence/fluorescence quantum yield ratios, and phosphorescence lifetimes of 12 thiophene benzologs of which the phosphorescence properties were unknown are reported.
A Theoretical Study of 2-Substituted Allyl Cations and Anions
Authors: Khalil Salim M.
Published: February 2015

MINDO-Forces calculations are reported, after complete geometry optimization, for 2-X-allyl cations and anions, where X is O- , OH, NH2, CH3, NO2, CN, CF3, F, CHO.In the case of the allyl cation, it was found that the substituents O- , OH, NH2 are stabilizing, CH3 is slightly stabilizing and all other substituents are destabilizing.In the case of the allyl anions, all the substituents are stabilizing. It was found that the substituents CH3, O- , CN show the amphielectronic behaviour. Calculations predict no (1,3) π interaction in 2-substituted ally cations and anions.
Comparison of Variational Solutions of the Thomas-Fermi Model in Terms of the Corrected Ionization Energy
Authors: Agil I. , Alharkan A. , Alhendi H . , Alnaghmoosh A.
Published: February 2015

It is shown that leading corrections, to the ionization energy, of many-electrons atom, can be expressed as leading corrections of initial slope of trial variational solutions of the Thomas-Fermi equation. Some variational solutions with different initial slopes are compared. A comparison of the results shows, that as far as the binding energies are concerned a trial function with its slope not close to the (negative) Baker’s constant may not be suited.
Newtonsche Aufheizung, Abelsche Integralgleichungen zweiter Art und Mittag-Leffler-Funktionen
Authors: Gorenflo Rudolf
Published: February 2015

The problem of heating a homogeneous half-space by radiation from outside across the plane boundary is considered. Newtonian heating means that the heat flux across the boundary is proportional to the difference of outside temperature and interior boundary temperature. The outside temperature is assumed to be constant and positive, the initial inside temperature is zero everywhere. The problem is onedim ensional in space. The temporal evolution of the inward boundary temperature obeys an Abel integral equation of second kind for whose explicit solution three methods are described (one by Laplace transform , the other two by infinite series defining the Mittag-Leffler function of index 1/2). The explicit solution facilitates discussion of its qualitative properties. Finally, the general Abel integral equation of second kind is treated by Mittag-Leffler functions.
On Topological Aspects of Ideal Fluid Flow and a Concomitant Singularity
Authors: Mulser P.
Published: February 2015

The meaning of the trajectory of a fluid element in the Lagrangian picture of fluid dynamics for neutral and charged particles is clarified and it is shown that the homeomorphism induced by the flow has some very general topological properties. Consequences on void closure and thermalization in impact experiments are illustrated.
Computation of Tokamak Equilibria With Steady Flow
Authors: Kerner W. , Tokuda S.
Published: February 2015

The equations for ideal MHD equilibria with stationary flow are re-examined and addressed as numerically applied to tokamak configurations with a free plasma boundary. Both the isothermal (purely toroidal flow) and the poloidal flow cases are treated. Experiment-relevant states with steady flow (so far only in the toroidal direction) are computed by the modified SELENE40 code.
Magnetic Field Line Diffusion at the Onset of Stochasticity
Authors: Elsässer K. , Deeskow P.
Published: February 2015

The Hamiltonian equations of a particle in a random set of waves just above the stochasticity threshold are considered both theoretically and numerically. First we derive the diffusion coefficient and the autocorrelation time perturbatively without using the thermodynamic limit, and we discuss the relevance of the H am iltonian problem for particle acceleration and magnetic field line flow. Then we integrate the equations for an ensemble of magnetic field lines numerically for a model problem [15] and show the time evolution of moments and correlations. Twice above the threshold we observe diffusive behaviour from the beginning, but the diffusion coefficient includes also the non-resonant modes. Just at threshold we find first a short phase o f free acceleration, later a diffusion which is slower than predicted by the theoretical formula. The best way to analyze the problem is in terms of cumulants, but a reliable com parison with any theory requires also a time integration of the corresponding kinetic equations.
Laser Acceleration of Particles with the Plasma Vector-Soliton
Authors: Horton W. , Tajima T. , Mima K.
Published: February 2015

The closed, energy conserving system of electromagnetic-plasma equations describing the classical beat wave accelerator are shown to lead to an intrinsic limit on the acceleration efficiency due to the pump depletion effect producing an intense trail of plasma waves. We propose and analyze with theory and simulations a wakeless accelerating structure composed of a nonlinear vector soliton. The solitary wave speed u o f the vector soliton can be greater than the group velocity of the electromagnetic pulse as determined by the laser intensity a0 = e E0/m ω0 c through the soliton dispersion relation. Combining the triple soliton structure with a weak plasma density depression of radius (c/ωp) (ω0/ωp)1/2, we compute an accelerating structure with Ep <̰ me ωp c/e moving at the speed of light and limited in length only by the conditions set by beam loading or plasma nonuniformities.
Hyperfine Structure in the Microwave Spectrum of Trifluorophosphine Oxide and Sulfide
Authors: Bittner Eric R. , Matos José , Hillig Kurt W. , Kuczkowski Robert L.
Published: February 2015

The microwave spectra of 17OPF3 and 33SPF3 were investigated by Fourier transform microwave spectroscopy and the 17O and 33S quadrupole coupling constants were determined. The 17O coupling constant is compared with several others from related phosphine oxides to characterize the π-bonding in these systems.
Phase Diagram of the System LaCl3-CaCl2-NaCl
Authors: Igarashi K. , Ohtani H. , Mochinaga J.
Published: February 2015

The phase diagram of ternary system LaCl3-CaCl2-NaCl has been constructed from the phase diagrams of the three binary systems and of thirteen quasi-binary systems determined by DTA. For the binaries LaCl3-CaCl2 and CaCl2-NaCl eutectic points were observed at 651 °C , 35.1 mol% LaCl3 and at 508 °C , 49.9 mol% NaCl, respectively. For LaCl3-NaCl, a peritectic point besides the eutectic point at 545 °C , 36.1 mol% LaCl3 was found at 690 °C , 57.5 mol%, which is attributable to the formation of the peritectic compound 3 LaCl3 · NaCl. The phase diagram of the ternary system has a ternary eutetic point and a ternary peritectic point due to 3 LaCl3-NaCl, the form er at 462 °C and 12.1 - 3 9 .7 - 4 8 .2 mol% (LaCl3-CaCl2-NaCl) and the latter at 612 °C and 26.9 - 55.1 - 18.0 mol%.
General Relations between Molecular Sensitivities and Their Physical Content
Authors: Nalewajski Roman F.
Published: February 2015

The molecular Legendre transformed representations are reexamined. They correspond to alter­native sets of parameters defining the constraints imposed on the system. In the global description the molecular (equilibrium) states are defined by the global state parameter G = (N or μ) and the state function f (r) = [υ(r) or n(r)]; N is the system number of electrons, μ its chemical potential, υ stands for the external potential due to the nuclei, and n is the electron density. In the local description, capable of defining non-equilibrium molecular density distributions, the state is defined by two state functions, g(r) = [n(r) or μ (r)] and f (r); here μ (r) is the local chemical potential of the electron distribution in small volume element around r. The Maxwell cross differentiation identities in both approaches, relating various molecular sensitivities, are physically interpreted. A qualitative discussion of general relations between molecular sensitivities is given and their physical content and possible applications are commented upon.
The Infrared, Raman, and Vibronic Spectra of Europium Chelates
Authors: Zachara S. , Szyncel M.
Published: February 2015

Absorption spectra in the far and intermediate infrared, as well as Raman and vibronic spectra were measured for three crystalline forms of four-ligand europium chelate with dibenzoylmethane and piperidine and a three-ligand chelate in the spectral ranges: 40-450, 450-4500, 0-4500 and 0-1600 cm - 1 , respectively.

The analysis of the individual spectra enabled the identification of the frequencies corresponding to the vibrations of the Eu -O bond coupled with the lattice vibrations, and the frequencies of the intraligand vibrations. It is found that piperidine is bound to the complex molecule by hydrogen bond.
Anomalous X-ray Scattering Study of GeO2Glass
Authors: Matsubara E. , Harada K. , Waseda Y. , Iwase M.
Published: February 2015

The anomalous X-ray scattering (AXS) technique was applied to a structural study of GeO2 glass, using synchrotron radiation and a new goniometer system. The environmental radial distribution function (RDF) was determined from intensity measurements at the Ge K absorption edge and compared with the ordinary RDF curve estimated from the. X-ray scattering intensity by Mo K α radiation. By combining the environmental and ordinary RDFs of the GeO2 glass it has been confirmed that the fundamental local unit structure is a GeO4 tetrahedron and that these tetrahedra are joined at their corners to form a network structure. The capability of the AXS technique has been approved as a relatively new tool for the structural characterization of disordered materials.
Testing of Stability and Spectroscopic Response of NiO(OH)/Ni2Si/n+/n-Si-Photoanode
Authors: Li Guozheng , Wang Shixun , Getoff Nikola
Published: February 2015

A stable multilayer n-type silicon photoanode is produced by evaporating or sputtering a thin nickel film on the silicon surface and subsequently annealing in argon atmosphere. Its properties are investigated under various conditions. Under irradiation with intense light at a constant potential, no appreciable decrease of the photocurrent was observed during a period of 100 hours, while oxygen gas was evolved. The action spectra of this photoanode, measured under different potentials, showed that its absorption extends in a broad region.
Photoinduced Transformation of Carbon Monoxide in Aqueous Solution
Authors: Park Hyoung Ryun , Getoff Nikola
Published: February 2015

The photoinduced conversion of CO in aqueous solution under the influence of vacuum-uv radiation at λ = 185 nm has been investigated at pH values ranging from 2 to 13. Formaldehyde, glyoxal, carboxylic acids and small amounts of glycol were determined as final products. Initial quantum yields for product formation have been determined. A probable reaction mechanism is presented.
The HETP in Exchange Electromigration and Chromatography for Isotope Separation
Authors: Klemm Alfred , Fujii Y. , Hosoe M.
Published: February 2015

The Height of an Equivalent Theoretical Plate (HETP) is a characteristic process constant for any separation column in which a small elementary effect is to be multiplied. The smaller the HETP. the steeper is the enrichment along the column. In order to determine the HETP experimentally, it is not necessary to bring the column into the final, stationary state. One can more readily evaluate it from the initial slope of the enrichment at a closed end of the column. This is demonstrated for isotope separations on lithium, copper, rubidium and uranium obtained recently by means of exchange electromigration and chromatography.
Internal Cation Mobilities in the Molten Ternary System(Li,Na,K)Cl of the Eutectic Composition
Authors: Endoh Akira , Okada Isao
Published: February 2015

For molten (Li, Na, K)Cl of the eutectic composition (53.5-8.6-37.9 mol%), in the temperature range from 773 K to 973 K the relative differences in the internal cation mobilities have been measured by the Klemm method, and the conductivity by a direct current method. From these data and the molar volumes, evaluated from those of the pure salts on the assumption of additivity, internal mobilities of the cations, bLi, bNa and bK, have been calculated. Below ca. 873 Kt bLi < bK < bNa, and above bu bLi < bNa < bK. These orders are interpreted in terms of the potential profiles for cations located between two Cl- ions. bLi and bK in the present ternary system can be fairly well expressed by function of the number density of Cl- ions presented previously for the binary system (Li, K)Cl.
Structural Phase Transitions in Solid tert-Butylammonium Nitrate as Studied by Differential Thermal Analysis and 1H-NMR
Authors: Ishida Hiroyuki , Iwachido Tadashi , Hayama Naomi , Ikeda Ryuichi , Hashimoto Miyuki , Nakamura Daiyu
Published: February 2015

Seven solid phases including three metastable phases of (CH3)3CNH3NO3 were revealed by differential thermal analysis in the temperature range between 80 K and the melting point (418 K), and cationic dynamics in each phase was studied by use of 1H-NMR techniques. The highesttemperature solid phase obtainable above 412 K was found to be an ionic plastic phase, where the cations perform rapid translational self-diffusion and overall rotation about their center of gravity.
A Model Study of Instabilities Present in the Mean-Field Description and in Linearized Correlation Schemes
Authors: Böhm Michael C. , Bubeck Gerd , Oles Andrzej M.
Published: February 2015

In this work we discuss the cooperative occurrence of instabilities in the Hartree-Fock (HF) approximation and linearized correlation models. Both breakdown phenomena can be analyzed via eigenvalues of characteristic matrices. The well known HF instabilities follow from a quasidegeneracy between the symmetry-adapted mean-field state and singly excited configurations. Quasi-degeneracies between the HF wave function and doubly excited configurations restrict the applicability of linearized correlation models. In the theoretical calculations the method of the local approach (LA) has been employed to derive the correlated ground state. For a system of the general topology XH2 (X = C, Si, etc.) the bond orbital approximation (BOA) has been used to derive analytic formulae indicating the stability range of linearized correlation schemes. Numerical calculations on the basis of a simple model-Hamiltonian are given for the π systems C2H4 and C2H2, respectively, which have been studied as a function of the CC bondlength. The comparison of the respective numerical data indicates that both breakdown phenomena are enhanced via coupling terms between strongly correlated bonds.
On the Insertion Reactions of CH2(ã1A1) in to Some Element-Hydrogen Bonds
Authors: Koch M. , Temps F. , Wagener R. , Wagner H. Gg.
Published: February 2015

Absolute values for the removal rates of CH2(ã1A1) by NH3, CH3NH2, CH3OH, HCl, and HF have been determined in the gas phase at low pressures and room temperature. CH2(ã1A1) was generated by pulsed laser photolysis of CH2CO. The measurements were carried out by observing the laser induced fluorescence of 1CH2 after excitation by a pulsed laser as a function of the time delay between the photolysis and analysis pulses. The overall rate constants were found to be 2.4, 2.4, 2.3, 1.6 and 0.13 · 1014 cm3/mol s, respectively.

NH2 was shown by LIF detection to be a primary product of the reaction of 1CH2 with NH3. The intersystem crossing channel of 1CH2 was investigated by monitoring the formation of CH2(X̃3B1) with laser magnetic resonance. LMR absorption intensities of 3CH2 resulting from quenching of 1CH2 in the presence and absence of the reactant R were compared under otherwise identical conditions. The branching ratios of quenching versus total removal of 1CH2, turned out to be 0.30, 0.13 and 0.98 for NH3, CH3OH, and HF, respectively.
Can Self-focusing of Intense Laser Beams Cause Bose -Einstein Condensation in to a Superfluid State ?
Authors: Winterberg F.
Published: February 2015

The cause of the phenomenon of self-focusing of intense laser radiation in solids is the nonlinear inten­ sity dependent refractive index [1] n = nl + n 2E2, (1)
Photophysical Properties of Hematoporphyrin and Dihematoporphyrin Ether (Ester)in Homogeneous and Microheterogeneous Environments
Authors: Köhler Gottfried , Getoff Nikola , Shopova Maria , Gantchev Tsvetan
Published: February 2015

Excitation wavelength effects on hematoporphyrin (HP) and hematoporphyrin derivative (HPD, Photofrin II) fluorescence spectra, quantum yields and decays were comparatively studied in homo­ geneous (at different pH and substrate concentrations) and microheterogeneous (Triton X 100 micelles and Bovine serum albumin) aqueous environments, in which the porphyrins are expected to be present in different monomer/aggregate equilibria. The observed wavelength dependences of the fluorescence yield and of short lived contributions to the total fluorescence do not correlate to the porphyrin aggregation state obtained from absorption spectra. In micro-heterogeneous environ­ ment the influence of local interactions between the porphyrin and hydrophobic sites of the cosolutes on HP and HPD photophysics is demonstrated.
On Electromagnetic Spinors and Electron Theory
Authors: Inskeep Warren H.
Published: February 2015

The relationship between the Dirac theory and electromagnetic spinors is extended to the case of finite mass. Certain products of the electromagnetic fields give rise to the Dirac differential operator upon the usual subsitutions for the energy and momentum. By placing mass in the proper place for the wave mechanical approach to quantum theory, the algebra of the fields, interpreted as quantum operators, may be deduced.
Corner-Cutting Tunneling in Hydride Transfer Between NAD+ Analogues
Authors: Kreevoy Maurice M. , Lee In-Sook Han
Published: February 2015

If hydride transfer from a donor, AjH, to an acceptor, Ai
+ , involves tunneling, phenomenological theory suggests a characteristic functional relation between rate constants and the equilibrium constant, i.e. between ln (kij, H/kij, D) and In Kij. Tunneling occurs at a heavy atom separation larger than that of the transition state (saddle point). This gives the critical configuration (point of no-return) for H-transfer a larger heavy atom separation than that for D-transfer and leads to the pattern described through a corollary of Marcus theory of atom transfer. The theory is called corner-cutting because it shortens the path which represents the reaction in multi-dimensional potential energy space. If the reactions are moderately spontaneous and the variation in structure which generates the variation in kij, H, kij, D and Kij is in the acceptor, the slope of the plot of ln (kij, H/kij, D) against ln Kij is expected to be negative; if the structure variation is in the donor it is expected to be positive. Similar results are expected for proton and hydrogen atom transfer.

This behavior has now been observed, for hydride transfer between various nitrogen heterocycles (all of which may be regarded as analogues of the enzymatic cofactor, NAD+). These reactions have kij, H/kij, D~ 5. The increase of kij, H/kij, D, with increasing Kij, reported in this paper, is particularly hard to explain without corner-cutting. The present results, therefore, support the view that some tunneling is involved in most hydrogen transfer reactions, even when no anomalies are obvious.
Deuterium Isotope Effects on the Presteady State Burstofan Enzymatic Reaction
Authors: Cleland W. Wallace
Published: February 2015

When a presteady state burst is seen in an enzymatic reaction where a change in absorbance accompanies the isotope-sensitive step, there will be an isotope effect on the initial rate of the burst. The apparent commitment which reduces the size of the intrinsic isotope effect will not be solely the partition ratio of the intermediate undergoing the isotope-sensitive step (as in steady state kinetics), but will also be a function of the ratio of the forward rate constants for the isotope-sensitive step and the one preceding it. A contour map of these relationships is presented.
Structure of Amorphous(Co,Mn)76B24-and (Co,Mn)85B15-Alloys by Means of X-Ray- and Neutron-Diffraction
Authors: Heckele M. , Lamparter P. , Steeb S. , Bellissent R.
Published: February 2015

Amorphous (Co1-xMnx)85B15
- (x = 0.07; 0.22; 0.39) and (Co1-xMnx)76B24- (x = 0; 0.07; 0.22) alloys were produced by melt-spinning and investigated by X-ray- and neutron-diffraction. The variation of x, i.e. the manganese concentration did not influence the X-ray intensity pattern, which suggests that no larger topological changes in the structure took place. However, using neutrons, the variation of x caused large intensity variations. These lead for large x to negative values in the total pair distribution functions g(R). From this behaviour it is concluded that cobalt and manganese cannot be mutually substituted but form a chemical short range order with preference for Co-Mn-pairs compared to Mn-Mn- and Co-Co-pairs. The metal-boron-correlations are preferentially cobalt-boron-correlations. The evaluation of measured data yielded no direct boron-boron-contacts.
Hydrogen in Electrodynamics III. The Hydrogen Spectrum
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.
The Liquid Phase of Superionic Conductors. MC Simulations of Molten Silver Iodide
Authors: Margheritis C.
Published: February 2015

MC simulations, in the NpT version, were carried out on molten Agl, on the basis of the literature interionic potentials proposed for the simulation of the superionic α-phase of solid Agl. A systematic analysis showed that none of the examined potentials can satisfactorily reproduce the experimental characteristics of the melt.

Moreover, it has been pointed out that tests of pair potentials through simulations at constant volume can be misleading.
Structural Study of the Molten CaO-Fe2O3 System by X-ray Diffraction
Authors: Suh In-Kook , Sugiyama K. , Waseda Y. , Toguri J. M.
Published: February 2015

The structure of molten CaO - Fe2O3, with CaO content from 33 to 60 mol% was studied by means of high temperature x-ray diffraction. At higher CaO concentrations the iron atoms were found to become more and more tetrahedrally by rather than octahedrally surrounded by oxygens. The present structural information is consistent with the reported results on the viscosity of this system.
The Determination of Spin-Rotation and Spin-Spin Interaction Constants from the Microwave Spectrum of Methane
Authors: Wolf P. , Stahl W.
Published: February 2015

High sensitivity and resolution of our microwave Fourier transform (MWFT) spectrometer and careful analysis of the measured transients enabled us to determine very accurate spin-rotation and spin-spin interaction constants of methane. In addition we were able to increase the accuracy of the existing centrifugal distortion constants.
On the Diabaticity of He+
2
Authors: Metropoulos A.
Published: February 2015

The strong diabaticity of the 2Σ+
g excited states of He+
2 has been computationally verified in the region of the well known avoided crossing between the 1 2Σ+
g and the 2 2Σ+
g adiabatic states. A large transition rate between these two states has been found, which is of the order of 1015 sec-1.
X-ray Structural Study of Ferromagnetic Vitreous 0.5 La0.7Sr0.3MnO30.5B2O3
Authors: Matsubara E. , Waseda Y. , Inomata K. , Hashimoto S.
Published: February 2015

The ordinary x-ray diffraction profile and the anomalous x-ray scattering profiles at Sr K-absorption edge were measured in a ferromagnetic oxide glass of 0.5La0.7Sr0.3MnO30.5B2O3. The result indicates the characteristic feature of coexistence of a highly ordered perovskite La0.7Sr0.3MnO3-like region and a random network structure consisting of BO3 triangles. It is expected that the characteristic magnetic properties of this sample are attributed to this distinctive structure.
Anomalous X-ray Scattering on Amorphous Al87Y8Ni5 and Al90Y10 Alloys
Authors: Matsubara E. , Waseda Y. , Inoue A. , Ohtera  , Masumoto T.
Published: February 2015

The structure of a new amorphous Al87Y8Ni5, indicating high strength and good ductility, was studied by anomalous X-ray scattering (AXS). For comparison, a binary amorphous Al90Y10 alloy was also investigated. The environmental radial distribution functions around Y and Ni as well as the ordinary RDF in the ternary alloy, and the environmental RDF around Y and the ordinary RDF in the binary alloy were determined. From the analysis of these RDFs it is found that the Y atoms are completely surrounded by Al in the binary alloy, and that some of these Al atoms are replaced by Ni atoms in the ternary alloy.
Self-Exchange Velocities in Molten (Li, Na, K)CI of the Eutectic Composition Reflecting the Chemia Effect for the internal [Mobilities
Authors: Endoh Akira , Okada Isao
Published: February 2015

Molecular dynamics (MD) simulation has been performed on molten (Li, Na, K)Cl of nearly the eutectic composition at 773 K, 873 K and 973 K. The employed pair potential parameters are based on the Tosi-Fumi ones except the softness parameter, which is somewhat modified. The self-exchange velocities (SEV’s) of Li+ , Na+ and K+ with reference to CP have been calculated. The sequence of the internal mobilities of these cations is well reproduced by the corresponding SEV’s, v; that is VLi < Vk < VNa at 773 K, VLi < VNa ≅ VK at 873 K and VLi < VNa < VK at 973 K
Substratum Interpretation of the Sagnac-and the Aharonov-Bohm Effect
Authors: Winterberg F.
Published: February 2015

It is shown that a substratum interpretation reveals a close relationship between the Sagnac- and the Aharonov-Bohm-effect. The characteristic peculiarity of the Aharonov-Bohm-effect, to produce a phase shift of the electron wave function even in the absence of any electromagnetic force fields, can be duplicated by a thought experiment for light waves in the gravitational field of a massive rotating cylinder, which demonstrates that the somewhat similar Sagnac-effect is not caused by centrifugal and Corioli’s forces, as it is sometimes claimed. In the substratum interpretation, both the Sagnac and Aharonov-Bohm effect find their explanation in a rotational motion of the substratum. If the substratum flow is irrotational, having the form of a potential vortex, these effects persist even though there are no force fields present.
Ionic Conductivity in the poly(propylene glycol)-poly(methyl methacrylate)-LiCF3SO3 System
Authors: Svantesson P. A. , Albinsson I. , Mellander B.-E.
Published: February 2015

The temperature dependence of the ionic conductivity in the PPG-rich part of the ternary system poly(propylene glycol)-poly(methyl methacrylate)-LiCF3SO3 has been investigated. The highest conductivity values, 3 x 10-5 (ohm cm)-1 at 31 °C and 4 × 10-4 (ohm cm)-1 at 77 C, were obtained for samples which had the properties of a pressure sensitive adhesive. The temperature dependence of the ionic conductivity could be well described by the Vogel-Tammann-Fulcher equation.
Kristallstruktur von SbCl4F / Crystal Structure of SbCl4F
Authors: Minkwitz Rolf , Konikowski Detlef , Preut Hans
Published: February 2015

The crystal structure of SbCl4F is reported. SbCl4F crystallizes in the tetragonal space group I 4̄

with a = 1278.4(6), c = 774.1(5) pm, V = 1265(1) • 106 pm3 and Z = 8. Four SbCl4F units are linked via symmetric Sb-F-contacts forming an eight-membered heterocycles.
Polysulfonylamine, LIV [1](12-Krone-4)lithiumdimesylamid-Acetonitril (3/2): Ein Kristall mit zwei prinzipiell unterschiedlichen Konformationen des gleichen Coronanden / Polysulfonylam ines, LIV [1] (12-Crown-4)lithium Dimesylamide-Acetonitrile (3/2): A Crystal with Two Fundamentally Different Conformations of the Same Coronand
Authors: Blaschette Armand , Nagel Karl-Heinz , Jones Peter G.
Published: February 2015

[Li(12-crown-4){N(S02CH3)2}] is obtained from equimolar amounts of lithium dimesylamide and 12-crown-4 in methanol and crystallizes from acetonitrile as a 3/2 solvate. The crystallographic data of the latter at -130 °C are: monoclinic, space group P 2/n, a = 1053.4(3), b = 904.3(3), c = 2791.2(8) pm, β = 95.66(3)°, V = 2.646 nm3, Z = 6, Dx = 1.441 Mgm-3. Apart from CH3CN molecules residing in lattice cavities, the structure consists of two crystallographically independent [Li(12-crown-4){N(S02CH3)2}] ion pairs A and B in the ratio 2:1. In B, the Li and N atoms lie on a crystallographic twofold axis. In both ion pairs, Li is hexacoordinated by the four crown oxygen atoms O(C) and by one oxygen O(S) from each sulfonyl group of the anionic ligand. The coordination geometry of Li in A closely resembles that of CuII in the known structure of [Cu(12-crown-4)Cl2] and can be pictured as a distorted octahedron, where two cis sites are occupied by the O(S) atoms and the remaining vertices by the four oxygens of the macrocycle, which displays a [4 8] conformation. The lithium atom, the two O(S) and two O(C) atoms are arranged in an approximately square-planar pattern with L i-O (S) 203.6 and 205.1, Li-O(C) 206.9 and 219.1 pm, trans angles of 173.7 and 174.8°, and cis angles in the range 87.1 -93.6°. The angle between the remaining two Li -O(C) bonds with distances 214.7 and 221.5 pm is only 146.5° compared with 180° in an ideal octahedron. In ion pair B, the coronand assumes a [3 3 3 3] conformation close to C4 symmetry, as observ­ ed e. g. in the known structures of [Li(12-crown-4)NCS] with a square-pyramidal 0 4N-coordination and [Ca(12-crown-4)(H20)4]Cl2 · 4 H2O with a square-antiprismatic 0 8-geometry. The coordination polyhedron in B can be viewed as an incomplete cube in which two vertices related by a face diagonal are unoccupied. Important bond lengths and angles in B are: L i-O(S) 216.8, L i-O(C) 214.0 and 228.7pm; O(S) -L i-O (S) 82.0, O(C) -L i-O(C) 75.7/76.3 for adjacent and 120.4/121.9° for opposite ring oxygens.
Cycloadditionen, XXI [1]. 2-Methyl-2,3-butadiensäure-arylester; Synthese und thermische Reaktivität / Cycloadditions, XXI [1] Aryl 2-methyl-2,3-butadienoates; Synthesis and Thermal Reactivity
Authors: Himbert Gerhard , Fink Dieter , Stürm Martina
Published: February 2015

The substituted phenyl, 1-naphthyl or the 9-anthrylmethyl esters of the 2-methyl-(or 2-phenyl)-2,3-alkadienoic acids (see 4 a -g , 9 a -d and 12a,b) are synthesized by condensation of the allenic acids 2 a -d with the substituted phenols 3 a -g , with 1-naphthol (8) or with 9-anthrylmethanol (11) in the presence of dicyclohexyl carbodiimide (DCC) and a catalytic amount of 4-dimethylaminopyridine (DMAP). An alternative route is the reaction of the acid chloride la with the phenols 3 a -c (see formation of 4 a -c) in the presence of triethylamine. All these compounds (except 12a) undergo the intramolecular Diels-Alder (IMDA)-reaction to form the tricycles 6 a -g , 10 a-d and 13. The enol ether 6a is hydrolized during chromatography to give the tricyclic ketone 7. The influence of the geminal methyl group on the rate of the IMDA-reaction is investigated.

9-Anthryl-and (2,4,6-cycloheptatrien-1-on-2-yl)-2-methyl-2,3-butadienoate (15, 17), formed by reaction of 2-methyl-2,3-butadienoyl chloride (1a) with 9-anthrone (14) and 2-tropolone (16) isomerise spontaneously to the IMDA-products 19 and 18.
Übergangsmetallkomplexe mit Schwefelliganden, C*. Unerwartet einfache Bildung von Diazen-Komplexen und ein neuer Typ von Diastereomerie: [µ-N2H2{Fe(PPr3)('S4')}2] und analoge Komplexe mit [FeS]-Zentren. ( 'S4'2-= 1,2-Bis(2-mercaptophenylthio)ethan(2-)) / Transition Metal Complexes with Sulfur Ligands, C*. Unexpectedly Facile Formation of Diazene Complexes and a New Type of Diastereomerism: [µ-N2H2{Fe(PPr3)('S4')}2] and Analogous Complexes with [FeS]-Centers. ('S4'2- = 1,2-Bis(2-mercaptophenylthio)ethane(2-))
Authors: Sellmann Dieter , Friedrich Helge , Knoch Falk , Moll Matthias
Published: February 2015

Single pot reactions of FeCl2∙4H2O with the tetradentate thioether-thiol 'S4-H2' = 1,2-bis(2-mercaptophenylthio)ethane, phosphines such as PEt3, PPr3 or PBu3, and a ca. 40-fold excess of N2H4∙H2O yield, in the presence of air, diazene complexes of the general formula [µ-N2H2{Fe(PR3)('S4')}2]. In contrast to previous syntheses of diazene complexes, the yields can excel 80%, and the syntheses can be carried out on a 10 g scale.

[µ-N2H2{Fe(PPr3)('S4')}2], 1 and [µ-N2H2{Fe(PEt3)('buS4')}2], 2 were characterized by X-ray structure analysis. 2 contains 'buS4'2−= 1,2-bis(3,5-ditertiarybutyl-2-mercaptophenylthio)-ethane(2-), which is the tertiary-butyl derivative of 'S4'2−. 1 and 2 contain trans-HN=NH which bridges enantiomeric [Fe(PPr3)('S4')] or [Fe(PEt3)('buS4')] fragments. HN=NH is stabilized by 4c - 6 e− - π bonds, strong tricentric N − H∙∙∙(S)2 bridges, and steric shielding. NMR studies show that centrosymmetric 1 isomerizes in solution at temperatures around 0 °C in order to give a diastereomerie diazene complex which is also centrosymmetric. The diastereomerism is traced back to bridging the chiral [Fe(PPr3)('S4')] fragments by trans-HN=NH in a different way. The two different bridging modes are verified by X-ray structure analyses of analogous ruthenium complexes. Because this new type of diastereomerism is basically caused by a different position only of the N − H∙∙∙(S)2 bridges, it is termed hydrogen bridge diastereomerism. A mechanism for the isomerization is suggested. 1 exhibits three anodic waves in the cyclovoltammogram. The second wave indicates formation of the dication [1]2+, which is a redox isomer of the diprotonated (and as yet hypothetical) dinitrogen complex [µ-N2{Fe(PPr3)('S4')}2]. The significance of [1]2+ and of its Lewis basic thiolate donors with respect to electrochemical reduction of molecular dinitrogen under mild conditions is discussed.
1.3-Dimethyl-1,3-diaza-2-R-5,6-benzo-2λ3-phosphorinan-4-one (R = F, Me2N, 2-Methylpiperidino, MeC(: 0 )N H -) als Liganden in Übergangsmetallkomplexen; Synthese und Struktur von Dichloro-Platin(II)- und Tetracarbonyl-Metall(O)- Koordinationsverbindungen (Metall = Cr, Mo und W) / 1.3-Dimethyl-1,3-diaza-2-R-5,6-benzo-2λ3-phosphorinan-4-ones (R = F, Me2N, 2-Methylpiperidino, MeC(: 0 )NH-) as Ligands in Transition-Metal Complexes; Synthesis and Structure of Dichloro-Platinum(II)- and Tetracarbonyl-Metal(0) Coordination Compounds (Metal = Cr, Mo and W)
Authors: Plinta Hans-Jürgen , Neda Ion , Schmutzler Reinhard
Published: February 2015

1,3-Dimethyl-1,3-diaza-2-fluoro-5,6-benzo-1,3,2-phosphorinane-4-one (1) reacted with (COD)PtCl2 (COD = 1,5-cyclooctadiene) or K2PtCl4 to give the cis-dichloro-platinum(II) complex (2). The reactions of 1 with the tetracarbonyl norbornadiene derivatives of Cr, Mo and W furnished the complexes 3 - 6 . In the case of the chromium and tungsten complexes the trans-isomers 3 and 6 were formed, due to a cis-trans-isomerization. Room temperature and low temperature 31P NMR spectra of a mixture of 5 and 6 show no significant temperature dependence of the cis-trans equilibrium. The reaction of 1 with the pentacarbonyl tetrahydrofuran derivative of W led to the product 7. The spirophosphoranes 8 and 9 were obtained in low yields. The analogous reactions of 10, 15 and 20 with (COD)PtCl2 and the tetracarbonyl norbornadiene derivatives of Cr and Mo furnished the coordination compounds 11-14, 16-18, 21 and 23. In the case of all chromium complexes only the trans-isomers 11,16 and 21 were formed, whereas in the case of molybdenum cis-trans-isomer mixtures 12 and 13, as well as 17 and 18 were obtained. An attempt to obtain the cis-isomer of the molybdenum complex 22 failed. In the case of platinum the expected cis-complexes 14 and 23 were formed, while the attempted synthesis of 19 was unsuccessful. All these results are interpreted in terms of both steric and electronic factors. The ligands 1, 10, 15 and 20 coordinate via phosphorus. The validity of the concept of hard and soft acids and bases (HSAB) was confirmed. The characterization of 2 - 7 , 11-14, 16-18, 21 and 23 rests, especially, on their 1H, 13C and 31P NMR spectra, and their mass and infrared spectra. 31P - 31P coupling constants 2J(PP) for the cis-coordinated complexes 4, 5 and 14 involving two equivalent phosphorus ligands are also reported.
On the Chemistry of Resiniferonol, II [1] Preparation and Bioactivities of 15,16-Dihydrosimplexin and Methods for its Tritium Labeling
Authors: Schäfer T. , Sorg B. , Karalai C. , Hecker E.
Published: February 2015

Excoecaria factor O 1 -the daphnane type polyfunctional diterpene ester 5 β-hydroxy-6 α,7 α-epoxyresiniferonol-9,13,14-orto-(2,4,6-decatrienoate) -may be obtained in reason­ able amounts from the latex of Excoecaria oppositifolia from South East Asia. O 1 was partially hydrogenated with H2-Pd/C to yield, by saturation of the three double bonds in the orthoester, and of ⊿15,16 in the diterpene moiety, the new 15,16-dihydro derivative of simplexin. The latter is the well known daphnane prototype of polyfunctional diterpene esters occurring in Euphorbiaceae and Thymelaeaceae. 15,16-Dihydrosimplexin (DHS) showed pro­nounced irritant and tumor promoting activities. By analogous hydrogenation of O1 with a mixture of 1H2/3H2 a selectively labeled [3H]DHS was obtained that exhibited a particularly high specific activity of 30 Ci/mmole. Thus it is considered most appropriate for use to study the toxicokinetics and -dynamics of daphnane type diterpene esters. To device an alternative of 3H-labeling of DHS or simplexin (SIM) in position 20 of the diterpene moiety DHS-5-benzoate was oxidized by pyridinium chlorochromate. The resultant 20-aldehyde was reduced by sodium borohydride to reconstitute DHS-5-benzoate and, after deprotection, DHS. This route appears appropriate to prepare similarly [20-3H]DHS as well as [20-3H]SIM using sodium [3H]borohydride.