bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study by Numerical Simulation of the Structural and Dynamical Properties of the Fused LiCl-KCl Eutectic
Authors: Lantelme F. , Turq P. 
Published: February 2015

The ionic properties of the eutectic LiCl-KCl melt are examined in a large range of temperature and density. The radial distribution functions are calculated. It is shown that, although the contribution of the Coulomb energy to the thermodynamic properties decreases at high temperatures it remains always predominant and explains the temperature dependence of the specific heat at constant volume.
The diffusion coefficients of Li+, K+ and Cl- are determined. The mechanism of the ionic motion is studied through the memory function formalism. Two types of motion are detected, which arise from binary collisions and from dynamical events which involve a large number of ions. Temperature and volume changes show that the lithium ions remain always surrounded by a more structured atmosphere which hinders their motion. This effect becomes more apparent at high temperature and low density.
A Microscopic Study of Motions in Supercooled 1,3-Butanediol
Authors: Soltwisch M. , Schneider F. , Quitmann D. 
Published: February 2015

Abstract
Quasielastic Rayleigh scattering of 14.4 keV Mössbauer γ-radiation has been measured on 1,3-butanediol, yielding the width Γ of the central line (assumed to be Lorentzian) and its relative intensity, for momentum transfers corresponding to molecular dimensions (k = 0.9... 2.5 Å-1) at 243 K. Γ (k) rises fast and then saturates. An effective correlation time τ and jump width is derived characterizing the diffusional motion of individual molecules considered as entities. Fast motions (vibrations, librations) are taken into account explicitly. The correlation time τ compares well with results from other experiments. The temperature dependence was followed from 208 up to 263 K.
Untersuchungen mit Hilfe der Elektronenzyklotronresonanz-(ECR)-Technik XVI .Wechselwirkung von HNO3 und CINO3 mit niederenergetischen Elektronen in der Gasphase / Studies by the Electron Cyclotron Resonance-(ECR)-Technique. XVI. Interactions of Thermal- Energy Electrons with the Molecules HNO3 and CINO3
Authors: Wecker D. , Schindler R. N. 
Published: February 2015

Using the ECR-technique the capture of thermal-energy free electrons was investigated by the molecules HNO3 and ClNO3. The following rate constants at room temperature were obtained:
k(HNO3) =(1.4 ±0.7)· 10-8 cm3 sec-1 ;
k (ClNO3) = (3.9 ± 1.2)· 10-9 cm3 sec-1 .
An apparent activation energy of AE = (1.6 ± 0.5) kcal · mol-1 was found for the reaction with ClNO3.
From the energy dependences of the both reactions together with thermodynamic considerations it is suggested that electron capture by ClNO3 occurs via dissociative attachment whereas with HNO3 a negative parent ion can be formed. Strong similarity is pointed out to exist between HONO2 and ClONO2 towards capture of electrons and the reaction with O2
- respectively.
Resistometric Evidence of Diffusional Mixing in Concentration Layered Amorphous AgCu Films
Authors: Reda I. M. , Wagendristel A. , Bangert H. 
Published: February 2015

In order to separate diffusion induced changes in the electrical resistivity of quench-condensed amorphous AgCu alloy films from such arising from other causes several trial experiments have been performed. Such films consisting of alternating Ag60Cu40/Ag40Cu60 layers showed a specific resistance rise which revealed the following peculiarities:
1. The duration of this increase is inversly proportional to the square of the individual Ag60Cu40/Ag40Cu60 couple thickness,
2. The increase is suppressed if rapid heating up to the crystallization temperature is performed and
3. It is not appearing in homogeneous layers.
These results give clear evidence that the observed effect is arising from diffusional intermixing only. Diffusion coefficients averaged over the annealing period are estimated as D = 8.7 x 10-15 cm2s-1 x exp 0.89 eV/kT.
Ab Initio-Rechnungen zur Protonenaffinität unverzweigter primärer aliphatischer Amine / Ab Initio-Calculations on the Protonaffinity of Unbranched Primary Aliphatic Amines
Authors: Heyne Eberhard , Raabe Gerhard , Fleischhauer Jörg 
Published: February 2015

Recently we reported the results of semiempirical calculations (MNDO, MINDO/3) which led us to the conclusion, that the proton-affinity of molecules R-NH2 (R = H, CH3, C2H5, n-C3H7 and n-C4H9) is determined by the ability of the groups R to carry positive charge in the corresponding cations R-NH3
+.
We did extend our investigations concerning the protonaffinities of primary aliphatic amines including NH3 and performed ab initio calculations with an STO-3G basis. The results qualitatively parallel those obtained by the semiempirical methods mentioned above.
In contrast to the semiempirical results we found that there is a satisfactory correlation between the Mulliken-charges of the nitrogen-atoms and of the NH2-groups and the experimental protonaffinities if NH3 is excluded.
Relativistische Verallgemeinerung des Lenzschen Vektors (I) / Relativistic generalisation of the Lenz vector (I)
Authors: Kern Eberhard 
Published: February 2015

The non-relativistic motion of a particle in a central field with 1/r potential, e.g. the motion of an electron in the Coulomb field of a charged nucleus at rest, is described by the equation of motion (non-relativistic Kepler problem) m x″ = α · x /r3 with α = ez e (product of the charges of the central body ez and the electron e). From this equation of motion, three statements of conservation can be derived: in respect of the energy E, of the angular momentum L and of the Lenz vector Λ = m {x′× L + α ·x/r}. The geometric meaning of Λ is that of a vector pointing in the direction of the perihelion of the particle orbits (conic sections).
It will be demonstrated that also at the relativistic Kepler problem, which is based on the equation of motion

an analogous Lenz vector exists. It represents a quantity of conservation - in the same way as the relativistic energy and the relativistic angular momentum. For the transitional case → ∞, where the relativistic problem turns into the non-relativistic problem, the relativistic Lenz vector also turns into the non-relativistic Lenz vector. The generalised (relativistic) Lenz vector has also a geometric meaning. Its direction coincides with the oriented axis of symmetry of the orbits (rosettes, spirals, hyperbola-type curves etc.).
The quantity of conservation Λ occupies a special position in respect of the quantities of conservation energy and angular momentum. Whereas the energy and the angular momentum correspond with a symmetry of time and space, the Lenz quantity of conservation corresponds with a symmetry of the orbits. The fact that the Lenz vector can relativistically be generalised touches thereby on principal aspects.
Reaction-Diffusion Dissipative Systems—Detailed Stability Analysis-Pattern of Growth and Effect of Inhomogenity
Authors: Nandapurkar P. J. , Hlavacek V. , Degreve J. , Janssen R. , Rompay P. Van 
Published: February 2015

A detailed stability analysis of the one dimensional steady state solutions for the Brusselator model under the conditions of diffusion of initial (non-autocatalytic) components has been performed both for zero flux as well as fixed boundary conditions. In addition to subcritical as well as supercritical bifurcations, situations have been observed where all solution branches at a bifurcation point are unstable. A case of degenerate steady state bifurcation (2 solutions emanating from the same bifurcation point) has also been noticed. A transient simulation of the system in growth reveals the importance of growth rate on the pattern selection process and suggests that the selection of branches at a bifurcation point may be influenced by perturbations/ fluctuations. It also indicates that a stability analysis of the bifurcation diagram alone cannot decide the state of the system in a transient process, and under certain situations complex behavior may be observed at limit points.
Numerical calculations on coupled cells indicate that a heterogenity in the system can introduce multiple (two) time scales in the system. As the ratio of time scales increases, aperiodic or irregular oscillations are observed for the 'fast' variable. A combination of cells with one cell in a steady-state mode and the other in a periodic motion results in a combined motion of the entire system. For a distributed parameter system, a heterogenity can cause development of sharp local concentration gradients, alter the stability properties of steady state as well as periodic solutions and can cause partitioning of the system.
Influence of the Reversible Energy Transfer on the Donor Fluorescence Quantum Yieldin Donor-Acceptor Systems
Authors: Bojarski C. 
Published: February 2015

Abstract
In mixed systems of donor and acceptor molecules having closely located S1 levels a reversible nonradiative energy transfer should occur. It influences remarkably the dependence of the donor quantum yield ηD on the acceptor concentration in the range of high acceptor concentrations of systems with high donor-to-acceptor reduced concentration ratios.
Determination of Dipole Moments by Microwave Fourier Transform Spectroscopy. Trifluoropropine, Tert.Butylisocyanide, and Cvanoacetylene
Authors: Kasten W. , Dreizler H. 
Published: February 2015

Abstract
We report the measurements of dipole moments by Microwave Fourier Transform Spectroscopy. Hereby we indicate that it is worth to supplement this type of microwave spectroscopy to increase its capability.
An Improved Variational Calculation of the Lower Vibrational Energy Levels of the Ammonia Molecule
Authors: Maessen Bärbel , Bopp Philippe , McLaughlin Don R. , Wolfsberg Max 
Published: February 2015

Abstract
A new variational calculation of the inversion spectrum of ammonia is reported in which all six vibrational degrees of ammonia are employed. By fitting spectroscopic data, an inversion barrier of 1810 cm-1 is obtained.
Substitution Structures of Gauche and Trans Isobutyraldehyde by Double Resonance Modulation Microwave Spectroscopy
Authors: Stiefvater O. L. 
Published: February 2015

Nine isotopic species of gauche- and seven isotopic forms of rra«.s-isobutyraldehyde, (CH3)2CHCHO, have been studied by DRM microwave spectroscopy to determine dihedral angles within and between the two rotameric conformations. In the gauche conformation one methyl group (subscript 3) eclipses the oxygen atom exactly, and best compatibility with the isotopic data is obtained when the two carbon-to-methyl bonds are assumed to be of equal length. The isotopic data for the less stable trans rotamer do not allow unequivocal determination of the bondlengths in the isobutyl skeleton, but bond angles and dihedral angles are determined satisfactorily. For both rotamers the geometry of the methyl groups was assumed with C - H = 1.088 Å and ∠ CCH = 110.2°.
The following bondlenghts (in Å) and angles (in degrees) are best compatible with the isotopic data:
[xxx]
The structural differences between the two rotamers are explained as due to repulsion between the bonds at either end of the rotameric axis.
Quantenchemische Rechnungen an Stickstoffbasen. Teil 4*: Zur Berechnung der Polarisierbarkeiten aliphatischer Amine mit der MINDO /3-FP-Methode
Authors: Niephaus Herbert , Raabe Gerhard , Fleischhauer Jörg 
Published: February 2015

The polarizabilities of some primary, secondary, and tertiary amines have been calculated with the MINDO/3-FP-method. The calculated values are found to correlate with the experimental polarizabilities and with those determined by the method of Miller and Savchik in a satisfying manner. In addition atomic polarizabilities have been calculated according to the method of Metzger. Averaging over the calculated mean atomic polarizabilities of hydrogen, carbon, and nitrogen yields increments which, when used to recalculate molecular polarizabilities, lead to values which correlate in an excellent manner with those determined from densities and refraction indices by means of the Lorenz-Lorentz-equation.
Because different nitrogen increments have been determined for primary, secondary and tertiary amines, the parameters presented here make it possible to distinguish between constitutional isomers as long as they belong to different groups (i.e. primary, secondary, and tertiary amines), something which cannot be done using the method of Miller and Savchik. The increments derived do not only allow to predict the polarizabilities of primary, secondary and tertiary amines but can be used to calculate the corresponding values for hydrazines and polyfunctional amines with equal success.
Determination of a High Potential Barrier Hindering Internal Rotation from the Microwave Ground State Spectrum The Methylbarrier of Antiperiplanar and Synclinal Normal Propyl Fluoride
Authors: Kasten W. , Dreizler H. 
Published: February 2015

The microwave ground state spectra of antiperiplanar and synclinal normal propyl fluoride have been measured by microwave Fourier transform spectroscopy and analysed for methyl torsion fine structure. Additionally, the spectrum of the synclinal form in the first excited state of the methyl group has been investigated due to methyl torsion. The difference of the values determined for the barrier heights in the ground and first excited state of the synclinal form is discussed by an approximate treatment of the coupling of CH3 and C - C torsional motions.
As high J transitions were measured a centrifugal distortion analysis was necessary.
Fifty Years of Nuclear Quadrupole Moments
Authors: Brix Peter 
Published: February 2015

On March 2, 1935 Hermann Schiller and Theodor Schmidt reported the first experimental evidence of non-spherical nuclei. From careful hyperfine structure studies of several Eu I-lines, they had shown that the hyperfine components of 151Eu and 153Eu did not follow the Lande interval rule exactly. Since the deviations were larger for 153Eu with the smaller magnetic moment, level perturbations were ruled out. This led to the conclusion of nuclear quadrupole moments. The theory was published June 1, 1935 by Hendrik B. G. Casimir. Nuclear deformations are playing a decisive role in modern nuclear structure physics. For solid state physics, spectroscopic quadrupole moments are very useful, since they probe the electric field gradient at the nuclei.
This review presents the discovery of 1935 in historical context: 1. Early measurements of nuclear radii. 2. Discovery of nuclear quadrupole moments. 3. Spectroscopic quadrupole moments (absolute measurements; relative hyperfine data, europium revisited). 4. Intrinsic quadrupole moments (discovery from isotope shifts; present status, samarium revisited). 5. Charge distribution of deformed nuclei.
Crystal Structure and Single Crystal 35Cl NQR of 1,2-Dichloro-3-Nitrobenzene, Cl(1)Cl(2)(NO2)(3)C6H3
Authors: Sharma Surendra , Paulus Helmut , Weiden Norbert , Weiss Alarich 
Published: February 2015

and single crystal
l,2-Dichloro-3-nitrobenzene, Cl(1)Cl(2)(NO2)(3)C6H3, was investigated by X-ray diffraction 35Cl NQR Zeeman spectroscopy. The crystal structure was determined, RW = 0.033. The compound crystallizes with the space group C2h
5
- P21/c, Z = 4; a = 381.0(1) pm, b = 1376.5(3) pm, c = 1430.2(3) pm, β = 97.764(5)°. From the
35Cl NQR Zeeman spectra it was found at 294 K: e2ΦzzQh-1 (
35Cl(1)) = 71.892(6) MHz, η(35Cl(1)) = 0.1287(25), e2ΦzzQh-1 (35Cl(2)) = 75.436(6) MHz, η(
35Cl(2)) = 0.1525(25). The angles (Φzz
(1),Φzz
(2)) and (Φzz
(2), C(3)-N(3)) are slightly opened in comparison to the corresponding X-ray bond angles. The temperature
dependence of ν(
35Cl) is reported.
Isotope Shifts in Ammonium Perrhenate
Authors: Haslett T. L. , Brown R. J. C. , Park Y. S. , Shurvell H. F. 
Published: February 2015

Isotope shifts in the NQR and Raman spectra o f ammonium perrhenate due to 15H and 2H substitution are reported. The effect of isotopic substitution at the nitrogen on the NQR spectrum is zero; in the Raman spectrum the translational lattice modes of the ammonium ion are clearly differentiated from the torsional modes.
The effect of deuteration on the NQR frequency has been measured to high accuracy and confirms that to a moderately good approximation the effect of deuteration is equivalent to the application of pressure. The effect of deuteration on the lattice parameters has been measured. NQR spectra of slightly deuterated ammonium perrhenate show a shoulder with a characteristic shift due to short range influence of NH3D+.
Symmetry Partitioning over Liouville Space for Evolution under the Anisotropic Quadrupolar Spin-Spin Interaction
Authors: Temme F. P. , Sanctuary B. C. 
Published: February 2015

The structure of the anisotropic indirect quadrupolar spin-spin interaction, and its effect on the spin dynamics associated with pure NQR time-domain response, is considered in terms of spherical tensor operator bases and multipole theory. The advantages of symmetry-adapting the Liouville bases is discussed for I ≧ 3/2 spin systems.
In particular, symmetrized state space bases for the n-fold quadrupole cluster under Sn are introduced and enumerated for I = 3 /2 and n ≦ 4, as an initial step in the process. Symmetrized Liouville space bases for the [A]2 problems involving [3/2 :3/2] and [5/2:5/2] spin pairs under the group S2 are presented to illustrate the structure of the multipole calculations of the spin evolution under the specific spin-spin interaction term. Such systems are of especial interest on account of the nature of the molecular solids Br2 and I2.
Quantumchemical Calculations on Nitrogen Bases. Part 6 *: Analysis of the Proton Affinities of Aliphatic Amines Using the Kitaura-Morokuma Scheme and the MINDO/3 Method
Authors: Raabe Gerhard , Fleischhauer Jörg 
Published: February 2015

The energy partitioning scheme of Morokuma et al. has been applied to the proton affinities of fourteen aliphatic amines. The electrostatic, the polarization and the charge transfer component of the proton affinities have been calculated using the MINDO/3 method. Two different sets of structural parameters have been used for the complexes of the bases and the attacking proton. Within the framework of the semiempirical method employed here, the electrostatic interaction between an attacking proton and the base was found to be positive as a result of the relative magnitudes of the repulsion terms used in the proton-electron and the proton-core interactions.
In the case of the polarization term our findings roughly parallel those of Morokuma. For one of the two sets of structural parameters a good and almost group overlapping correlation was found between polarization energies and experimental proton affinities: the polarization part was found to decrease with increasing proton affinity. Independent of the choice of the amine geometries, the results for the charge transfer energy contradict the nonempirical data of Morokuma: Contrarily to his results we found values which increase in the order ammonia < methylamine < dimethylamine < trimethylamine.
Comparative Study of the Reactions of 16OH and 18OH with H16O2.
Authors: Dransfeld P. , Wagner H. Gg. 
Published: February 2015

The gas phase reactions

18OH + H16O2 → H2
18O + 16O2 (1a)

18OH + H16O2 → 16OH + H18O16O (1b)
were studied at room temperature in a discharge flow reactor with far infrared laser magnetic resonance (LMR) detection of 16OH, 18OH and H16O16O. The formation of 16OH in the course of the reaction was observed. The absolute rate constant for the overall removal of 18OH in excess of H16O16O was determined. Each run was accompanied by a control experiment replacing the initial 18OH by the same amount of 16OH. From these experiments a branching ratio is obtained of
k1a/( k1a + k1b) = 0.52 ± 0.08
Raman-Spektren des Calcium und Barium-ortho-Thiophosphates
Authors: Brückner Wolfgang , Pätzmann Ulrich 
Published: February 2015

The ortho-Thiophosphates Ca3(PS4)2 and Ba3(PS4)2 have been prepared and their Raman spectra recorded. The observed frequencies of the title compounds are assigned on the basis of tetrahedral PS4
3- units (Td symmetry).
The formation of ortho-Thiophosphates with cations in the oxidation state 2(Me3
II(PS4)2) is quite uncommon.
Characterization of the Phenanthrene-Tetrachlorophthalic Anhydride (P/TCPA) 1:1 Charge-Transfer Crystal: Spectroscopic and Structural Investigations
Authors: Krzystek J. , Schütz J. U. von , Wolf H. C , Stigler R.-D. , Stezowski J. J. 
Published: February 2015

The 1:1 phenanthrene-tetrachlorophthalic anhydride (P/TCPA) charge-transfer complex crystalizes with monoclinic symmetry, space group P21, with two magnetically inequivalent stacks in the unit cell. The noncentrosymmetric space group is very unusual for CT-complexes. The optical emission spectra at low temperature are characterized by a strong CT phosphorescence and a weak CT fluorescence and delayed fluorescence.
The S1 band lies at 22 800 ± 100 cm-1, the T1 band at 21 200 ± 100 cm-1. Above 15 K triplet excitons, moving along the stacks are revealed by ESR. They have a CT character of about 30%, coinciding with that of the shallow X-traps found by ODMR at low temperatures. A further trap, with zero-field-splitting (zfs) parameters of D = ± 0.0617, E = + 0.0116 cm-1 has a much larger CT character of 50% as found in the isolated complex in low-temperature glass [1]. A structural model is proposed.
Methyl Group Rotation and Tunnellingin Crystals of 5-Membered Ring Molecules
Authors: Montjoie A.-S. , Müller-Warmuth W. , Stiller Hildegard , Stanislawski J. 
Published: February 2015

Abstract

1H NMR spin-lattice relaxation times T1 and -if accessible -level-crossing peaks and inelastic neutron scattering spectra have been measured for solid 2-and 3-methylfuran, 2-and 3-methylthiophene, 3-and 4-methylpyrazole, 1-methylimidazole, and 5-methylisoxazole. From the tunnel splittings, the torsional excitations and the NMR relaxation rates, the molecular dynamics of the methyl rotators has been evaluated between the limits of quantum tunnelling at low temperatures and thermally activated random reorientation at elevated temperatures.
Energietransfer im System Ca3La2W2O12:Mn,Nd,Yb
Authors: Hirrle R. , Kemmler-Sack S. 
Published: February 2015

Abstract
Energy Transfer in the System Ca3La2W2O12:Mn, Nd, Yb
On codoping of the host Ca3La2W2O12 with Mn4+ and Nd3+ or Mn4+ and Yb3+ ,respectively, an efficient energy transfer Mn4+ → Nd3+ or Mn4+ → Yb3+ operates. The simultaneous introduc­tion of Mn4+ , Nd3+ and Yb3+ yields additionally an energy transfer Nd3+ → Yb3+ . The excitation, emission and diffuse reflectance spectra are discussed.
Gas Phase Basicity of Substituted Benzaldehydes and Methylbenzoates.A Semiempirical Molecular Orbital Study
Authors: Fabian Walter 
Published: February 2015

Abstract
The semiempirical AM1 method is used to calculate relative proton affinities of a series of meta-and para-substituted benzaldehydes and methylbenzoates. Close agreement between the results of these calculations and experimental relative gas phase basicities could be obtained. The influence of a substituent on the stability of both neutral as well as protonated forms is estimated via isodesmic reactions. In any case the influence of a substituent is most pronounced in the protonated carbonyl compound. The contribution of the inductive/field effect of a substituent is approximated by the results of isolated molecule calculations. The resonance contribution is estimated by the charge transfer to or from the substituent as revealed by a Mulliken population analysis. Alternatively, the difference between isodesmic stabilization energies and isolated molecule results for the protonated compounds is taken as a measure for the resonance effect. Linear regression analyses with these substituent parameters show good correlation with both experimental as well as calculated relative basicities of the compounds studied.