bluuebunny/crossref_metadata_2025 huggingface dataset:
Topological Effect on MO Energies, II.
Authors: Polansky O. E. , Zander M. , Motoc I.
Published: February 2015

The recently introduced approach of S, T isomers [1] has been applied to aza-benzenes and aza-perylenes. Ab initio and HMO calculations as well as experimental results clearly show that the S.T approach is a suitable means to derive definite predictions concerning the MO patterns and HOMO energies of structurally related aza-arenes.
The Dependence of the Internal Vibrational Frequencies of Liquid Water on Central Force Potentials
Authors: Jancsó G. , Bopp P.
Published: February 2015

The differences in the liquid phase internal vibrational frequencies of water, obtained from molecular dynamics (MD) simulations, between the two versions of the central force model of Rahman and Stillinger (CF1 and CF2) are investigated by employing the theory of Buckingham on solvent effects. It is found that the differences can be essentially accounted for by the different O-H stretching cubic anharmonic force constants of CF1 and CF2. A significantly improved agreement between the results of MD simulations and spectroscopically observed liuqid phase frequencies could be achieved by using a harmonic force field, supplemented by a cubic stretching force constant, for the intramolecular interactions of water, and the CF2 potential for the intermolecular interactions.
NMR Studies on Intercalation Compounds of Layered Chalcogenides with Methylamines and Ammonia
Authors: Molitor M. , Müller-Warmuth W. , Spieß H. W. , Schöllhorn R.
Published: February 2015

NMR wideline and pulse techniques have been used to study orientation and molecular motions of the intercalation compounds of niobium disulfide with monolayers of mono-, di-, and trimethylamine, tetramethylammonium and ammonia. Specific information has been obtained from the 1H and 2D spectra and from spin-lattice relaxation measurements of the selectively deuterated monomethylamines. Models for the arrangement of the various molecules within the layers and for the motions have been derived. One-dimensional rotation of CH3 and NH3 groups, rapid intermolecular exchange of NH, NH2 and NH3 protons, as well as translational and reorientational motions of whole molecules are of importance. Interpretation of spin-lattice relaxation rates at various temperatures and frequencies yields details of some of these motion and numerical values for the activation energies.
On the Order-Disorder Phase Transformation of Anilinium Halides
Authors: Schweiss Bernd Peter , Fuess Hartmut , Fecher Gerhard , Weiss Alarich
Published: February 2015

The order-disorder phase transition which occurs at Tc = 296.9 K in anilinium bromide, C6H5NH3Br, is studied by inelastic neutron time-of-flight measurements. Data are taken from hydrogenated and partially deuterated samples (C6D5NH3Br and C6H5ND3Br) below and above the transition temperature. From the inelastic scattering data the phonon frequency distribution in the range of the intermolecular vibrations is calculated. The assignment of bands is given and changes in the spectra with temperature are discussed. The analysis of the quasielastic line revealed substantial broadening due to rotational diffusion of the -NH3
⊕ group. These jump diffusion processes were observed in the orthorhombic high temperature and - with markedly diminished rate - in the monoclinic phase below Tc. From the correlation times at different temperatures the activation energies are estimated for both phases. Comparison with calculated elastic incoherent structure factors suggests jumps of 60° for hindered rotation.
Elektronenspektren p-donator-substituierter Benzonitrile und Benzoesäureäthylester/ Electronic Spectra of p-Donor Substituted Benionitriles and Ethylbenzoates
Authors: Wermuth Günter
Published: February 2015

The positions of 1La and 1Lb type absorption bands as well as the fluorescence polarization and natural lifetime show that p-donor substituted benzonitriles emit from a 1Lb-state. On the other hand, the nature of the lowest excited state of p-substituted ethylbenzoates depends upon the kind of the donor. In case of a dialkylamino group as donor substituent the emission occurs from the 1La-state, in case of weeker donors, like methoxy, from the 1Lb-state. In the intermediate case of p-aminoethylbenzoate the excited state depends upon the polarity of the solvent.

The 1Lb← 1A transition occurs at higher wave numbers for the donor substituent ethylbenzoates than for the correspondingly substituted benzonitriles, although the ester group represents the stronger acceptor substituent than the nitrile group in spectroscopic respect. This effect is interpreted using perturbation theory according to Petruska.
Relaxation Time Studies of Excited Oxido-Substituted p-Oligophenylenes in Different Solvents
Authors: Kawski A. , Alicka M.
Published: February 2015

Effective volumes, moments of inertia and Debye relaxation times in the excited state were determined for some oxido-substituted p-oligophenylenes by the method of fluorescence depolarization in nonpolar and polar solvents of different viscosities.
Hydration Phenomena in a Concentrated Aqueous Solution of Ce(NO3)3. X-ray Diffraction and Raman Spectroscopy
Authors: Caminiti R. , Cucca P. , D′Andrea A.
Published: February 2015

The scattering of X-rays from a concentrated Ce(NO3)3 aqueous solution has been measured and analyzed. The experimental correlation function appears to be mainly characterized by the hydration of the cation: peaks at about 2.55 and 4.65 Å. Good agreement with experimental data is achieved through a model in which the Ce(III) ions have a first and a second hydration shell and also the nitrate group is considered hydrated. Complex formation between cation and anion is confirmed by using Raman spectroscopy.
Einfluß der Reaktionsenthalpie auf die Bildung von "Twisted Intramolecular Charge Transfer" (TICT) — Anregungszustände in unpolaren Lösungsmitteln: p-substituierte N,N-Dimethylaniline / The Influence of Reaction enthalpy on the Formation of “Twisted Intramolecular Charge Transfer" (TICT)-States in Inert Solvents: p-Substituted N,N-Dimethylanilines
Authors: Wermuth Günter
Published: February 2015

In saturated hydrocarbons dual fluorescence appears both in p-N,N-Dimethylaminobenzonitrile (DMABN) and p-N,N-Dimethylaminoethylbenzoate (DMABEE). The temperaturedependence of the fluorescence quantum yield suggests that in DMABEE E(B*) ≈ E(TICT) and in DMABN E(B*) <E(TICT)
Centrifugal Distortion and Ground State Internal Rotation Analysis of the Microwave Spectrum of Dimethylsulfoxide
Authors: Fliege E. , Dreizler H. , Typke V.
Published: February 2015

The torsional Fine structure of dimethylsulfoxide has been reinvestigated with MWFT-spectroscopy. The higher resolution results in a more accurate determination of the internal rotation barrier V3. The centrifugal distortion analysis is extended to sixth order. The prediction of lines is excellent, but some centrifugal distortion constants are poorly determined
Hochaufgelöste vibronische Spektren von Al(acac)3 : Cr3+/Highly Resolved Vibronic Spectra of Al(acac)3: Cr3+
Authors: Schönherr Thomas , Eyring Gerd , Linder Rolf
Published: February 2015

Highly resolved emission spectra of Cr3+ doped Trisacetylacetonatoaluminum(III) have been measured at various temperatures. By comparison with absorption spectra of dilute crystals the three most intense peaks have been assigned to the same molecular zero phonon transition according to three inequivalent Cr3+ sites in the low temperature phase of the host crystal. The usually unobserved ground state splitting has been resolved (1.0 cm-1) in emission spectra at T = 1.9 K. Band assignments are confirmed by ligand Field calculations using complete trigonal perturbation matrices including spin-orbit coupling. From the obtained parameters K = 725 cm-1 and K′ = - 600 cm-1 the trigonal distortion of the chromium complex in the Al-crystal is determined. This indicates that the phase transition of the host crystal leads to rotations of rigid molecules while the molecular geometry remains.
Molecular Structure and Mesomorphic Properties of Thermotropic Liquid Crystals. II. Terminal Substituents
Authors: Osman Maged A.
Published: February 2015

The effect of terminal polar and nonpolar substituents on the thermodynamic stability of the mesophase is discussed. Mesomeric as well as steric effects influence the packing of the molecules and consequently the clearing point. It is necessary to consider the effect of substituents in connection with the nature of the rigid core. The influence of molecular association and conformational equilibria on the stability of the mesophase is described. Isolated electron densities lead to repulsions between neighbouring molecules, thus destabilizing the mesophase and the layered structure if present.
Energy Conserving Non-relativistic Guiding Center Mechanics and the Galilean Principle of Relativity
Authors: Wimmel H. K.
Published: February 2015

Arguments and representative examples are given that suggest that exact energy conservation and Galilei invariance are incompatible in non-relativistic guiding-center mechanics. Provided that this is true in general it also follows that exact energy conservation and Lorentz invariance are incompatible in relativistic guiding-center mechanics. It would furthermore follow that every guiding-center mechanics with exact energy conservation is a non-unique theory owing to the principle of relativity. The paper also presents a Galilei invariant guiding-center mechanics that does not conserve energy.
Molecular Dynamics Studies on the Structure of Binary Metallic Glasses based on Lennard-Jones (12-6) Potentials
Authors: Beyer O. , Hoheisel C.
Published: February 2015

For the metallic glass Ni81B19 the partial pair-distribution functions are determind up to 14Å by a molecular dynamics simulation using effective Lennard-Jones potentials. The obtained pair-distribution functions are in good agreement with the measured ones. As the simulation was carried out at the thermodynamic conditions for a liquid, we conclude that the characteristic features of the structure of the metallic glass are essentially not different from those of the fluid system Ni81B19 at high temperature and pressure. Both the high reduced density of the system and the large differences in the atomic radii of the two species dominantly determine the form of the partial structure factors of the glass. These Findings have been confirmed by our molecular dynamics simulation of a further metallic glass, the Cu57Zr43 system.
Fused Salt Concentration Cells with Transference. Transport Numbers of Molten (Li, Ag)Cl and Molten Alkali Jodide and Silver Jodide Mixtures
Authors: Richter J. , Kirschbaum E. , Valenta H.
Published: February 2015

The transport numbers of the molten systems (Li.Ag)Cl, (Na.Ag)I, (K,Ag)I, and (Rb,Ag)I have been determined by e.m.f. measurements on concentration cells with transference. With the exception of (Na,Ag)I, for these systems the existence of inversion points (the mobility ratio reverses at a certain mixing ratio) is proven within experimental accuracy. For (Na,Ag)I an inversion point might exist at the high Agl concentration side.
The Reaction of Hydrogen Atoms with Silyl Radicals; the Decomposition Pathways of Chemically Activated Silanes
Authors: Wörsdorfer K. , Reimann B. , Potzinger P.
Published: February 2015

The reactions of hydrogen atoms with silane and the methylated silanes - with the exception of tetramethylsilane -have been investigated in a fast flow reactor. Under our experimental conditions hydrogen abstraction from the Si-H bond is followed by combination of hydrogen atoms with the corresponding silyl radicals. The molecules formed in this way are activated by about 375 kJ/mol of vibrational energy. Two decomposition channels have been unequivocally identified, namely the elimination of molecular hydrogen and of methane, both with concomittant formation of the respective silylenes. In a subsequent step, silylene inserts into the substrate under formation of disilanes. With increasing degree of methylation. stabilization of the activated molecule competes with decomposition and dominates the kinetics in the case of trimethylsilane. With methyl -and dimethyl-silane, methyl radicals are observed as an additional reaction product. On the basis of RRKM calculations it is unlikely that they originate from a direct decomposition of the activated molecules.

Absolute values for the room temperature rate constants of the abstraction reactions are given; for H+CH3SiH3, Arrhenius parameters have been determined.
Magnetically Induced Plasma Rotation and the Dense Plasma Focus
Authors: Witalis E. A.
Published: February 2015

Fusion for Fission fuel breeding and other incentives for unconventional magnetic fusion research are introductorily mentioned. The design, operation and peculiar characteristics of dense plasma foci are briefly described with attention to their remarkable ion acceleration and plasma heating capabilities. Attempts for interpretations are reviewed, and a brief account is given for an explanation based on the concept of magnetically induced plasma rotation, recently derived in detail in this journal. Basically an ion acceleration mechanism of betraton character it describes in combination with a dynamic, generalized Bennett relation focus plasma characteristics like the polarity dependence, the current channel disruption, the axial ion beam formation and the prerequisites for the ensuing turbulent plasma dissipative stage. Fundamental differences with respect to mainline fusion research are emphasized, and some conjectures and proposals are presented as to the further development of plasma focus nuclear fusion or fission energy production.
Dissipative Structures in 1D and 2D Chemically Reacting Systems
Authors: Nandapurkar P. , Hlavacek V.
Published: February 2015

A transient analysis of the 1D and 2D reaction-diffusion equations associated with the model reaction of Prigogine and Lefever (Brusselator model), including diffusion of the initial (sub-strate) component, has been performed. For low system lengths and for fixed boundary conditions, the steady state low amplitude solutions are unstable. For zero flux boundary conditions a multiplicity of symmetric solutions with the same wave number may exist, the majority of them being unstable. The diffuion of initial components induce relaxation oscillations in space both for fixed as well as zero flux boundary conditions. The amplitude of the oscillation increases as the diffusion coefficient of the initial component decreases. For conditions of relaxation oscillations the spatial profiles result in single or multiple propagating fronts. High system lengths (or low diffusion coefficient of intermediate components), for both zero flux and periodic boundary conditions, may give rise to a multipeak incoherent wave pattern. For periodic boundary conditions a multiplicity of waves has been observed. Numerical simulation of the 2D-spatial structures reveal certain similarities between the 1D and 2D cases.
Infrarotspektren der Hexachalkogenohypodiphosphat-Mischkristalle Ni2P2S6-xSex und Co2-xNixS6 / Infrared spectra of the hexachalcogenohypodiphosphate mixed crystals Co2-xNixP2S6 and Ni2P2S6-xSex
Authors: Kliche G.
Published: February 2015

The hexachalcogenohypodiphosphate mixed crystals Co2-xNixP2S6 and Ni2P2S6-x Set have been prepared and characterized by x-ray powder methods and infrared spectroscopy. The spectra of the anionic substituted mixed crystals show the existence of mixed anionic species like e.g. P2S5Se or P2S4Se2. Cationic substitution leads to a one mode behaviour of the internal modes of the P2S6-units with different frequency shifts for the Eu and A2u modes and a two mode behaviour of the external modes.

Attempts to prepare mixed crystals Co2P2S6-xSex failed; only small amounts of selenium can be detected in Co2P2S6.
Neutron Diffraction Study on the Structure of the Metallic Glass Cu57Zr43
Authors: Lamparter P. , Steeb S. , Grallath E.
Published: February 2015

The structure of amorphous Cu57Zr43 has been investigated by neutron diffraction using the isotopic substitution method with the isotopes 63Cu and 65Cu besides natural Cu. From the scattering contribution of concentration fluctuations to the measured structure factors and from the atomic distances chemical ordering is concluded to exist in amorphous Cu57Zr43. The structural results are compared with previous experimental and theoretical investigations of Cu- Zr- and other binary metallic glasses formed by transition metals. Evidence is given that the topological as well as the chemical short range order is asymmetric in respect to both components in this type of metallic glasses
Das Modell der magnetischen Nahbereichs-Kopplung in seiner Erweiterung und Anwendung auf Gallium-Dotiertes α-Cr2O3 / The Extension of the Magnetic Cluster-Model and its Application to Gallium-doped α-Cr2O3
Authors: Dräger K.
Published: February 2015

The cluster model, developed for the ESR-absorption of a pure antiferromagnetic compound, has been modified to take into account the magnetic dilution. As bonding in a cluster is sensitive to its local geometry, the consideration is confined to the specific structure of α-Cr2O3. In this case, the incorporation of diamagnetic Ga3+ ions sets up eight local configurations with different coupling energies and distinct probabilities. It is assumed that the ESR-absorption of a doped crystal can be explained by the absorption within these configurations. The theory is able to predict the dependence on temperature and concentration for the ESR-intensity of gallium-doped Cr2O3 with an accuracy of about 3%. Numeral results of this fit are the magnetic coupling energies K1 = 183 cm-1 between nearest Cr3+ neighbours and K2 = 82.3 cm-1 between next-nearest Cr3+ neighbours
The Equations of Motion for Nematics
Authors: Vertogen G.
Published: February 2015

The fluid dynamics of nematics is discussed in terms of an approach based upon Rayleigh's dissipation function. In this way the derivation of the equations of motion becomes quite transparent.
Assignment of the Low Energy Photoelectron Spectrum of the Octa-Sulphur Molecule: An ab initio Configuration Interaction Study
Authors: Palmer Michael H.
Published: February 2015

A large basis set ab initio configuration interaction study of S 8 has yielded a satisfactory assignment of the first 5 IP's of the UV-photoelectron spectrum for the first time. The ionisation potential order (low to high) is 2A1, 2E3, 2E2, 2E1 ≪
2B2 and follows the orbital ordering of our recent large basis spd calculation, via the application of Koopmans' theorem.
Influence of an Orienting Field on the Viscosity of a Molecular Liquid
Authors: Hess Siegfried
Published: February 2015

From phenomenological consideration follows that both the field-induced anisotropy of the shear viscosity and the effect reciprocal to the flow birefringence contribute to the anisotropy of the effective viscosity in a Couette or a Poiseuille geometry, as well as to transverse effects and normal pressure differences. A Fokker-Planck equation approach links these mechanisms and yields a relation between two viscosity coefficients associated with the molecular orientation.
Über die Löschung von „Twisted Intramolecular Charge Transfer" (TICT)-Fluoreszenzen durch äußere Schweratom-Störer
Authors: Rettig W. , Zander M.
Published: February 2015

The quenching by methyl iodide and ethyl bromide of the TICT fluorescence of N-(p-cyanophenyl)- carbazole (II) and N-(l-naphthyl)-carbazole (III) has been studied in solvents of different polarity. It is found that the heavy atom induced bimolecular fluorescence quenching increases with increasing energy of the TICT fluorescence transition, contrary to the energy-gaprule, and that TICT states are much less readily quenched than locally excited (LE) states. These results are explained by assuming a very small S-T energy gap for TICT states and a solvent polarity dependent distribution function for the intramolecular twist angle.
Ab initio CI Study of the Ground and Excited States of CuF2 and CuCl2
Authors: Ha Tae-Kyu , Nguyen Minh Tho
Published: February 2015

Ab initio configuration interaction (CI) calculations of the ground, electronically excited and the ionized states (cations) are reported for CuF2 and CuCl2. The calculated results are compared with available experimental values of the UV spectrum of CuCl2 and the ionization potentials obtained from the photoelectron spectrum of CuF2.
The Effect of Pressure on the Hydrogen Bond Structure of Liquid Water
Authors: Pálinkás G. , Bopp P. , Jancsó G. , Heinzinger K.
Published: February 2015

The results of molecular dynamics simulations of low and high pressure liquid water using a modified central force potential have been analyzed in order to study the effect of pressure on the hydrogen bond structure of water. The properties investigated and discussed include the hydrogen bond angle distribution, the O -O distance distribution between the neighbour molecules, the structure of the first coordination sphere in the high density liquid and the average number of hydrogen bonds.
The Magnetic Booster Target Inertial Confinement Fusion Driver
Authors: Winterberg F.
Published: February 2015

A promising candidate for a near-term low-cost inertial confinement fusion driver is the magnetic booster target concept. In it a small high density magnetically confined plasma and which serves as booster stage, is compressed and ignited by hypervelocity impact. The energy released in the magnetic booster stage, after being transformed into black body radiation, ablatively implodes a high gain second stage target and which releases most of the thermonuclear energy. Alternatively, the energy released in the booster stage can be also used to compress and ignite a target as in impact fusion. The importance of this concept is that it permits to drive the booster stage with a mass accelerator at a velocity of a few 10 km/sec, which is small compared to the velocity required for pure impact fusion, even though it is more than one order of magnitude larger than what can be directly reached with ordinary guns or high explosives. The required velocities can probably be reached by magnetic guns and by fluid dynamic methods through the implosion of cylindrical or spherical shells driven by light gas gun fired projectiles. In comparison to laser- or charged particle beam drivers, the initial driver power is several orders of magnitude smaller and which should lead to a substantial reduction in the driver cost.
Calculation of Infrared Transition Probabilities for the 1Σ+Groundstate of XeH+
Authors: Klein Robert , Rosmus Pavel
Published: February 2015

Near equilibrium potential energy and dipole moment functions have been calculated for the electronic ground state of the XeH+ ion from highly correlated SCEP/CEPA electronic wavefunctions. The following spectroscopic constants for 132XeH+ are obtained:

Re= 1.611 ± 0.005 Å, ωe = 2313 ± 50cm-1, ωexe = 41 ± 5cm-1 and D0(Xe+ + H) = 3.90 ± 0.1 eV.

Infrared transition dipole matrix elements and probability coefficients for 132XeH+ and 132XeD+ are given. The electric dipole moment functions of the protonated rare gas atoms HeH+ to XeH+ are discussed.
On the Connection of Nonrenormalizable and Renormalizable Unified Nonlinear Spinor Field IVfodels
Authors: Stumpf H.
Published: February 2015

The nonrenormalizable first order derivative nonlinear spinor field equation with scalar interaction possesses two equivalent Hamiltonians. The first is the conventional one while the second is a two-field Hamiltonian with the original field and its parity transform. By quantization the latter leads to an inequivalent representation compared with the former. This is connected with parity symmetry breaking and the loss of simultaneous diagonalization of energy and subfield particle numbers. The corresponding grand canonical Hamiltonian is shown to result equivalently from a renormalizable second order derivative nonlinear spinor field equation. This is achieved by means of a theorem about the decomposition of higher order derivative nonlinear spinor field equations derived previously
Electric Field-Induced Birefringence in Liquid-Crystalline Blue Phases
Authors: Porsch F. , Stegemeyer H. , Hiltrop K.
Published: February 2015

The optical behaviour of liquid-crystalline 'Blue Phases' (BP) of polar cholesterogenic compounds in electric Fields up to 100 kV • cm-1 has been investigated by means of polarization microscopy. By an observation parallel to the field direction a birefringence dependent on the Field strength was detected in the BP I. This result is discussed in terms of a non-linear electrooptic effect, showing that the BP I becomes optically biaxial in an electric field. In the BP II a birefringence was not observed under the same conditions probably indicating that the field induces an optical uniaxiality with the optic axis parallel to the field. The results are discussed with respect to possible cubic structures of the BPs
The Rotational Barrier About the Disulphide Bridge in Dimethyl Disulphide: An Ab Initio Study
Authors: Renugopalakrishnan V. , Walter R.
Published: February 2015

An ab initio molecular orbital technique was used to investigate the rotational barrier about the disulphide bridge in dimethyl disulphide. Various minimal and extended basis sets were used in the calculations. The chosen minimal basis set was the STO-3G set, and the extended basis sets were the STO 4-31G set, the Dunning and Hay set consisting of contracted Gaussian basis sets: [2s], [3s, 2p] and [6s, 4p] for H, C, and S atoms, and the Dunning and Hay basis set augmented with a d-type function on S atoms. The total energy was calculated as a function of the torsion angle about the disulphide bond. The barrier to rotation about this bond was found to be two-fold in nature, in accordance with previous findings. The heights of the barriers were observed to depend upon the basis set and input geometry. For our particular choice of basis sets and input geometry, the calculated value of the eis and trans barriers ranged from 12.68 to 16.49 kcal/mol and from 6.23 to 8 kcal/mol, respectively. Inclusion of a d-type function in the basis sets was found to result in better agreement between the calculated and experimental values, thereby emphasizing the need for considering 3d orbitals of sulphur in MO calculations
Mikrokristallbildung und intermolekulare Triplett-Triplett-Energieiibertragung in festen transparenten Glasern bei 77 K. Das System N-Methylcarbazol/Naphthalin / Microcrystal Formation and Intermolecular Triplet-Triplet Energy Transfer in Rigid Transparent Glasses at 77 K. The System N-Methyl-earbazole / Naphthalene
Authors: Zander M.
Published: February 2015

The efficient intermolecular triplet-triplet energy transfer between N-methylcarbazole (donor) and naphthalene (acceptor) observed at 10-2 ᴍ concentration of donor and acceptor in a rigid transparent methylcyclohexane/n-pentane glass at 77 K is shown to occur in microcrystals of the donor containing small amounts of the acceptor
Preferential Solvation of Silver (I) Bromate in Methanol-Dimethylsulfoxide Mixtures
Authors: Janardhanan S. , Kalidas C.
Published: February 2015

The solubiltiy of silver bromate, the Gibbs transfer energy of Ag+ and BrO3
- and the solvent transport number in methanol-dimethyl sulfoxide mixtures are reported. The solubility of silver bromate increases with addition of DMSO. The Gibbs energy of transfer of the silver ion (based on the ferrocene reference method) decreases, while that of the bromate ion becomes slightly negative with the addition of DMSO. The solvent transport number A passes through a maximum (⊿ = 1.0 at XDMSO = 0.65. From these results, it is concluded that the silver ion is preferentially solvated by DMSO whereas the bromate ion shows no preferential solvation.
Dielectric Relaxation in Methanol-Acetonitrile Mixtures
Authors: Stockhausen M. , Dachwitz E.
Published: February 2015

The complex permittivity of methanol + acetonitrile at 20 °C was measured over the whole composition range at frequencies up to 36 GHz. It can be described by superposition of two Debye type components, one of them being due to associated methanol. This component is discussed with respect to two simple models, considering relaxation as governed by rotational tumbling of associates or by fluctuation of hydrogen bonds. The latter description appears to be the more suitable one.
Theoretical Studies on the Effect of N-Substitution on the Hydrogen Bonds of Metal Ion/Water/Amide Complexes
Authors: Sagarik Kritsana P. , Rode Bernd M.
Published: February 2015

The effect of N-substitution on the hydrogen bonds of metal ion/water/amide complexes is studied on Li+/N-methylformamide-water as an example. Using the energies and Mulliken atomic populations derived from ab initio calculations with minimal GLO basis set, the Li+/Nmethyl formamide-water and Li+/formamide-water complexes are compared. The transference of the effect of metal ions along the molecular structure seems to have a profound relationship to the bond polarizabilities of the backbone atoms. This can be discussed qualitatively in terms of changes in the Mulliken atomic publications.
Millimeterwave Spectrum and Centrifugal Distortion Analysis of Fluoroacetonitrile in the Ground State
Authors: Guarnieri Antonio , Tolkmit Gerhard
Published: February 2015

The millimeterwave spectrum of fluoroacetonitrile (CH2FCN) in the ground state has been investigated in the region between 50 and 150 GHz. The transitions have been fitted to a Hamiltonian using three rotational constants, five quartic and seven sextic centrifugal distortion constants in the symmetric top reduction by van Eijck and Typke and in the s-reduction of Watson. Further Watson's "determinable constants" have been calculated.
Vibrational Spectra and Force Constants of Symmetric Tops, XLIII [1] Fourier Transform Infrared Spectra of Monoisotopic H3GeBr Species in the ν1/ν4 and ν6 Region
Authors: Bürger H. , Eujen R. , Rahner A. , Schulz P. , Cradock S.
Published: February 2015

Fourier transform infrared spectra of the monoisotopic species H3
74Ge79Br and H3
74Ge81Br have been recorded in the ν1/ν4 region near 2100 cm-1 with a resolution of 0.015 cm-1 and in the ν6 and 2 ν6 regions near 580 and 1150 cm-1 with a resolution of 0.04 cm-1. Rotational analyses based on ~ 1500, ~1100 and ~ 300 data of ν1/ν4, ν6 and 2 ν6 respectively for each isotopomer have been performed, and ground state and excited state vibrational, rotational and rovibrational parameters have been determined, ν1, 2115.815 0(2)/2115.813 4(2) cm-1, and ν4, 2126.016 5(1) 2126.016 7(1) cm-1 (H3
74Ge79Br/H3
74Ge81Br), are weakly coupled by Coriolis x, y resonance, ζ1,4 ≃ - 0.021. ν6, 577.601 2(4)/577.541 7(4) cm-1, and ν4 are affected by / (±2, ±2) resonance. Furthermore, the hot bands (ν1+ν3)-ν3, (ν3+ν4)-ν3, (ν3+ν6)-ν3, 2ν6
±2 - ν6
±2 and 2ν0
6 - ν6
±1 have been detected and analyzed.
The Endoperoxide of Tetrabenzopentancene. A New Photochromic Endoperoxide
Authors: Schmidt R.
Published: February 2015

The thermal and the photochemical reactions of the endoperoxide of Tetrabenzo(bc,fg.lm,pq)- pentacene have been investigated with respect to its photochromic properties. The thermal yield of irreversible rearrangement reactions was determined to be Adec = 0.045. From the activation parameters of the thermal cycloreversion. forming the parent hydrocarbon and oxygen, a half life time of 114 years at 20 °C has been extrapolated. For the quantum yield of the irreversible photochemical rearrangement a value of Qdec = 0.03 was obtained. As can be seen from the wavelength dependence of the photocycloreversion quantum yield Q1, cycloreversion occurs not only from the thermalized S2(πccπ*cc) but from higher excited states too. The maximum quantum yield was found at 302 nm to be (Q1 = 0.15. From our results it follows that this endoperoxide is of high quality in respect to the colour change colourless/blue and to thermal stability, whereas the reversibility is only moderate.
On the Continuum Between the Solid and the Liquid State
Authors: Süssmann G.
Published: February 2015

With a view on nuclear matter, the continuity between the solid and the liquid states of a material is discussed. For such a viscoelastic medium an acoustical analogue of the Kramers- Kronig relation of linear optics is derived.
ESR of the . CD3 ... I- adduct in γ-irradiated 12CD3I and 13CD3I Crystals
Authors: Claesson O. , Lund A.
Published: February 2015

An alkyl radical-iodide anion adduct .CD3... I- has been detected in γ-irradiated 12CD3I and 13CD3I by ESR measurements on single crystals at 77 K. The species has hyperfine couplings of A = 80 · 9G. A⊥ = 39G with 127I and A =80G. A⊥ = 20 G with 13C. By comparison with INDO calculations it is concluded that the . CD3 group is planar with the I- ion at adistance of ca. 3 Å and located on the . CD3 three-fold axis.
Total Scattering Cross Section of Solids for Cold and Epithermal Neutrons
Authors: Granada J. R.
Published: February 2015

Simple expressions are given which accurately describe the total cross section of solids at cold and epithermal neutron energies. They are intended to provide a consistent procedure for the evaluation of solid state effects, which must be substracted from the experimental data when information is wanted on intrinsic nuclear properties. The formulae presented here are the asymptotic forms to which the full expressions reduce in those energy limits. A Debye model is adopted to describe the frequency spectrum of the solid. The present results are compared with some commonly used expressions as well as with the exact formalism. The effect of temperature is discussed and numerical calculations are presented for some cases.
Analytical Evaluation of the Hadron Number in Extensive Air Showers for Rising Inelasticity
Authors: Sidhanta Jiben , Roychoudhury Rajkumar
Published: February 2015

A purely analytical method is presented in this paper for evaluating the average number of hadrons (in an air shower) with a given energy as the inelasticity of the cross-section rises. Our result is found to be in excellent agreement with numerical solutions and also with experimental data, particularly in the high energy range.
Cation Transport in Low Density Ethene and Cyclopropane Gases
Authors: Gee Norman , Floriano M. Antonio , Freeman Gordon R.
Published: February 2015

Cation mobilities were independent of applied electric field strength over the range 0.06 ≦ (E/n)/Td ≦ 25 in ethene, and 0.07 ≦ (E/n)/Td ≦ 81 in cyclopropane. In the saturated vapors the density normalized mobility nμ+ was independent of vapor density over the range 0.2 ≲ n/1025 molec m-3 ≲ 80; nμ+ = (1.95 ± 0.09)/1021 molec m-1 V-1 s-1 in ethene and (1.43 ± 0.07)/1021 molec m-1 V-1 s-1 in cyclopropane. The constancy was caused by the virtual cancellation of small temperature and density effects. In the nonsaturated gases at constant density the temperature coefficient nμ+ was positive at 200 K, but decreased to near zero at 600 K. The momentum transfer cross sections σm were dominated by ion-induced dipole interactions at 0.06 ≲ ε/eV ≲ 0.2. At lower energies a softer potential, such as ion-quadrupole, made a major contribution, while at higher energies the hard core potential contributed significantly.
Preferred Rotameric Conformations of Isobutyraldehyde, Their Dipole Moments and Vibrationally Excited States by Microwave Spectroscopy
Authors: Stiefvater O. L.
Published: February 2015

The earlier prediction of the preferred and the less stable rotameric conformations of isobutyraldehyde, (CH3)2CHCHO, has been confirmed experimentally by microwave spectroscopy. The compound exists mainly in a gauche conformation, in which one of the methyl groups is eclipsed by the oxygen atom, and the less stable rotamer is the trans conformation, in which the oxygen atom eclipses the isopropyl hydrogen.

Ground state rotational constants (in MHz) and centrifugal distortion constants (in kHz), together with dipole moments (in D), are:

Rotation spectra due to three torsionally excited states of each rotamer have been identified, along with satellites arising from CH3 internal rotation and CC2 wagging.
Ultrasonic Absorption and Relaxation Phenomena in Molten Nitrate Mixtures
Authors: Richter J. , Fuchs B.
Published: February 2015

An optical device based on the Debye-Sears effect is developed to determine the ultrasonic absorption and velocity in molten alkali nitrate + silver nitrat mixtures. RbNO3 + AgNO3 and CsNO3 + AgNO3 are investigated in the total composition range between 480 K and 580 K within a frequency interval from 10 MHz to 35 MHz. In the concentration range of high ultrasonic absorption we find dispersion and a frequency dependent step in the absorption curve caused by relaxation. The relaxation time of the structural relaxation in the molten salt mixtures investigated here is in the order of 10-8 s.

The volume viscosity, the adiabatic constant, and the compressibilities are calculated.
Determination of Approximate Superstructures in the Urea-Hexadecane Inclusion Compound by Representation Analysis
Authors: Boysen H. , Forst R.
Published: February 2015

The inclusion compound of urea with hexadecane has a superstructure of an ideal hexagonal structure found in other members of the series of urea-n-paraffin adducts consisting essentially of honeycomb-like channels formed by the host into which the long chain molecules are embedded. In order to elucidate the nature of the superstructure, which manifests itself by addiditonal weaker reflexions ( h k l/2) and (0 0 l) (all l = integer), it is expanded into basis functions transforming as the irreducible representations (IR’s) of the average space group P6122. Most of the IR’s can be ruled out by exploiting the symmetry of the diffraction pattern. For the remaining sets of basis functions a least squares fit to the measured intensities is performed separately for each IR. Those yielding reliable agreements are then taken as key IR ’s describing the prevalent modulations. In this way it is possible to obtain valuable information about the main characteristics of the superstructure, even if the true structure cannot be fully determined. In the present case a strong modulation belonging to the A3 IR was found to produce rotations of the urea molecules around axes parallel to the channels as well as slight lateral translations. An additional contribution from Γ5 results in a superposition of individual orthorhombic domains with slightly different hydrogen bond angles. A phase transition below 147 K can be attributed to M2 and is connected with an ordering of the guest molecules and a simultaneous orthorhombic deformation of the channels.
14N Nuclear Quadrupole Coupling and Methyl Internal Rotation of 2-, 4-, and 5-Methyl Oxazole
Authors: Fliege Eckhard , Dreizler Helmut , Meyer Michael , Iqbal Khalid , Sheridan John
Published: February 2015

In the following we give an outline of 14N nuclear quadrupole, internal axis method (IAM) methyl internal rotation, and fourth order centrifugal distortion - only needed for extrapolating transition frequencies to higher J values - analyses performed for 2-, 4-, and 5-methyl oxazole.

The results are discussed, the three methyl oxazoles being compared with one another and with their common parent, oxazole.
Electrical and Structural Properties of Thin Palladium Films
Authors: Anton R. , Häupl K. , Rudolf P. , Wißmann P.
Published: February 2015

The electrical resistivity of thin palladium films deposited on amorphous substrates is measured in dependence on film thickness. The data are interpreted with the help of a statistical model taking into account structural information obtained from AES, TEM and x-ray diffraction texture analysis. The steep decrease of resistivity in the ultra-thin thickness region can be immediately correlated with the formation of coherent areas in the films. A more flattened course is reached at about 8 nm thickness where a continuous film structure develops.
Fourier Transform IR Spectra and Rovibrational Investigation of Monoisotopic H3
116Sn35Cl, H3
116Sn79Br and H3
116SnI in the υ6 Region
Authors: Betzel M. , Bürger H. , Rahner A.
Published: February 2015

Fourier transform infrared spectra in the υ6 region of the unstable monoisotopic species H3
116Sn35Cl, H3
116Sn79Br and H3
116SnI have been recorded with a solution of 0.04 cm-1 (0.12 cm-1 for H3SnI). Rotational J and K structure of the υ6 fundamental has been resolved for H3SnCl and H3SnBr, while Q branches were measured for H3SnI. The hot bands (υ3 + υ6) - υ3 and 2υ6
±2 - υ6
±1 have been identified. A rovibrational analysis has been performed, and the following band centers (for given A0 values) have been determined: H3
116Sn35Cl 488.786(2), H3
116Sn79Br 473.493(2) and H3
116SnI 453.680(9) cm-1.
Internal Cation Mobilities and their Isotope Effects in the Molten System (Li, K)Cl
Authors: Lundén Arnold
Published: February 2015

With the Klemm method, the internal m obility ratios of the Li and K. 6Li and 7Li, and 39K and 41K have been measured for melts o f the system (Li. K)Cl near the eutectic composition (ca. 56% Li) in the range 729 -976 K. Under all these conditions the Chemla effect occurs, i.e. bLi<bK. (b- internal mobility). In the region near the anode the com position becomes that corresponding to the Chemla crossing point, which shifts with temperature toward higher concentration of Li+. Both bLi and bK have been found to be well expressed by the equation b = [A/( V - V0)] exp ( - E/RT ) (V: molar volum e. A and E: constants depending on the respective cation. V0: a parameter depending on the respective cation and temperature), which is also valid for the mobilities in alkali nitrates when the C oulom bic attraction plays a dominant role. The isotope effects o f both cations seem to be similar to those in pure LiCl and KCl and slightly increase with temperature.
The Infrared Spectrum of Diazirine, H2C15N2 Rovibrational Analysis of the V3 Fundamental
Authors: Vogt Jürgen , Gambi Alberto
Published: February 2015

The mid-infrared spectrum of 15N-labeled diazirine has been recorded using a Fourier transform spectrometer at a resolution of 0.08 cm-1. The v3 fundamental at 1452.49 cm-1 which essentially corresponds to a symmetric methylene deformation has been analyzed in detail. The rovibrational assignment is given and, using Watson’s A-reduced Hamiltonian, the rotational and centrifugal distortion constants for the v3 = 1 level could be determined.
Quadrupole Interactions of Muonium in Crystals
Authors: Baryshevskii V. G. , Kuten S. A. , Rapoport V. I.
Published: February 2015

The properties of muonium having an electric quadrupole moment in crystals are briefly reviewed. A detailed analysis of the experimental situation in α-quartz is given, since the α-SiO2 lattice is a place of localization of not only muonium, but also of hydrogen and deuterium atoms. The temperature and isotopic dependences of the experimentally determined parameters of the quadrupole interaction of hydrogen, deuterium and muonium, as well as the nature of their trapping sites in the α-quartz lattice are discussed. It is shown that the change of the quadrupole interaction strength and symmetry with temperature is caused by the diffusion of muonium. It is mentioned that a significant role in explaining the isotopic dependence is played by the zeropoint vibrations of the hydrogen-like atom localized in the lattice.
Electric Quadrupole Moment of the 14N Nucleus Determined by ab initio Cl Calculation on NH3
Authors: Ha Tae-Kyu
Published: February 2015

Based on the calculated electric field gradient (q) from ab initio Cl wavefunctions with large

basis set (including ƒ functions on N and d functions on H) and the experimental nuclear
quadrupole coupling constant (e Q q) for nitrogen in NH3, an improved value o f the quadrupole moment of 14N is proposed as Q (14N ) = 2.08 x 10-26
cm2. The value calculated using a wavefunction
near the Hartree-Fock limit enlarged ≈ 10% by the Cl treatment.
Investigation of EFG Parameters at the Halogen Site in XO3 and XO3
2⊝ Radicals (X = Cl, Br) in Certain Inorganic Solids
Authors: Umasasidhar Y. , Ramaprabhu S. , Rao K. V. S. Rama
Published: February 2015

Electric field gradients at the halogen site in XO

3
and XO
3
2⊝
radicals (X = Cl, Br), formed by
the γ-irradiation of single crystals of NaClO3 , KClO3 , KBrO
3
and Sr(BrO3)2 · H20 have been
evaluated by MO calculations using the CNDO/2 method. The symmetry of the XO
3
radicals isassumed to be that of XO3
⊝ ions which have C3v symmetry, whereas XO3
2⊝
radicals are assumed
to have CS symmetry with one X -O bond distance being stretched due to the excess electron.
The results are in good agreement with the experimental values deduced from published ESR
studies on these single crystals.
NQR Spectra of 79Br and 127I in the Halogen Derivatives of the Benzoic and Hippuric Acids
Authors: Babushkina T. A. , Volgin K. Yu. , Gushtchin S. F.
Published: February 2015

Quadrupole interactions in ortho-, meta- and para-Br- and I-benzoic and hippuric acids have been studied by means of NQR spectroscopy. It is shown that the formation of the Na-salts results in NQR frequency changes. The temperature dependence of the 79Br and 127I NQR frequencies in the para-halogen derivatives of the benzoic and hippuric acids are investigated. The 127I NQR spectra in a few derivatives of 2, 4, 6-I3C6H2COOH are studied at 77 K.
Nuclear Quadrupole Resonance in Chloro- and Bromoantimonate(III) Complexes
Authors: Okuda Tsutomu , Tanaka Nobuhiko , Ichiba Sumio , Yamada Koji
Published: February 2015

C1,

3581Br, and 121Sb N Q R spectra were observed in com plexes o f the type RxSbyX z with anion
stoichiometries SbCl4 , SbClg- , SbBr4 , SbBr^~, SbBr^- , and Sb2Br^~. Several complexes show
widely spaced halogen resonance lines and unusual temperature dependences o f the NQ R
frequencies. These findings are accounted for
Dynamical Quadrupole Interactions in the Hafnium Deuterium System
Authors: Forker M. , Freise L. , Simon D. , Saitovitch H. , Silva P. R. J.
Published: February 2015

The nuclear quadrupole interaction (NQI) at the site of 181Ta in HfD2 has been investigated by time differential perturbed angular correlation measurements. Below 290 K the NQI is static within a 300 nanosecond time window. Above 290 K dynamic effects related to the diffusion of deuterium atoms start to appear, which have been analyzed in terms of a 3-state stochastic model. Between 345 K and 500 K the jump diffusion of deuterium has an activation energy Ea = (0 .3 3-0.4
+0.9 ) eV. At higher temperatures the relaxation spectra suggest that transitions occur, first to the δ-phase, then to the α-phase of the hafnium-deuterium system. At 600 K the mean residence time between jumps is of the order of 2 nanoseconds. First measurements with HfH2 show an isotope effect compatible with the prediction of the classical rate theory for over-barrier diffusion.
The Motion of the OH Group in p-Chlorophenol and its Influence on the 35Cl NQR Parameters
Authors: Zuriaga Mariano J. , Martin Carlos A.
Published: February 2015

The 35Cl NQR transition frequencies and the spin-lattice relaxation times, T1, for both lines in p-chlorophenol have been measured in the temperature range 90 - 310 K. The frequency difference and the temperature derivatives for both lines clearly show the existence of two temperature intervals with distinct lattice contributions to the EFG. Similarly, T1, data show a normal behaviour due to spin-phonon interactions up to 240 K. Above this temperature T1 begins to shorten in an exponential manner. The hindered motions of the OH group are proposed as responsibles of these effects, and an activation energy of 26 kJ mol-1 is determined.