bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Mathematical Structure of the New-Tamm-Dancoff Procedure
Authors: Feist W. 
Published: February 2015

Abstract
The New Tamm-Dancoff method is a procedure for the approximate determination of differences of eigenvalues in quantum field theory. This procedure can be formulated mathematically in the framework of the theory of C*-algebras, especially in our case by using von Neumann's infinite tensor products. Calculational rules are presented for operators which obey the canonical anticommutation relations. The concept of the CAR tensor product is introduced for the joint treatment of a system algebra and the associated functional algebra, A conjugation is discussed which will be needed for a proof of equivalence in II.
Molecular Orbital Theory of the Electronic Structure of Organic Compounds
Authors: Grinberg Horacio , Nudelman Norma Sbarbati , Marañón Julio , Sorarrain Oscar M. , Gómez Carlos F. 
Published: February 2015

Abstract
The semiempirical molecular orbital CNDO/S-CI spectral parameterization has been used to elucidate the lower electronic states of a series of dioxodiazacycloalkanes. The a1, b1, and a' occupied molecular orbitals lie predominantly on the oxygen, while a2, b2, and a" are largerly nonbonding orbitals delocalized on the nitrogen and oxygen atoms. The two lowest unoccupied virtual orbitals are predicted to be of b2, a2, and a" symmetry. These orbitals are strongly localized on the C = 0 group. The resulting 1 B2(u0π*) and 1 A2(n0π*) spectroscopic states involve intramolecular charge transfer from the oxygen to the carbon atom of the carbonyl group, which is supported by electron density calculations of these excited states. Although the calculated transition energies may not allow for absolute comparisons with experimental values, it appears that the introduction of self-consistency together with solvation energy and configuration interaction, when the elements of the interaction matrix are properly evaluated, lead to a fairly good interpretation of the singlet-singlet transitions. The lowest energy singlet excited state calculated for each structure is comprised almost entirely of the nπ* configuration.
Untersuchungen über die Chemilumineszenz der Reaktionen von Lithium mit Halogenen
Authors: Neuert H. 
Published: February 2015

Abstract
The chemiluminescent radiation from the reaction of lithium with the halogens Cl2, Br2, I2 and some halogenated molecules has been registered in the visible region. A beam-gas device was used at gas pressures of about 10-2 mb and Li-oven temperatures of 1000-1100K. The spectral lines from the Li atomic states are prevailing. In the Li-SF6 reaction, excitations approaching the ionisation limit of Li are observed. The distribution of the population of the excited states is given for some cases. The mechanism of the reactions is discussed in the light of the corresponding reactions of Na, K, Cs with the halogens, as described in the literature. The participation of the Li-dimer in the reaction processes is evident. No Li-halide fluctuation band structures were found. Strong Li2-A-X-, -B-X- and -C-X-bands appear in nearly all the spectra at higher Li-beam intensities, the excitation of which is discussed. Further molecular bands were observed, emitted from electronically excited states of the halogen molecules Br2 and I2. It is supposed that they are produced by energy transfer collisions mainly from the Li-halide molecules vibrationally excited in their electronic ground state. The appearance of molecular bands from electronically excited states of CuCl and CuBr in the spectra is described.
On the Unified Theory for Non-Equilibrium Phenomena in the Isotropic and Nematic Phases of a Liquid Crystal; Spatially Inhomogeneous Alignment
Authors: Hess S. , Pardowitz I. 
Published: February 2015

Abstract
A nonlinear equation is derived which describes the relaxation of the alignment and the flow alignment in the isotropic and nematic phases of a liquid crystal. In addition to the previously treated case, contributions associated with spatial derivatives of the alignment are taken into account which stem from gradient terms occuring in the free energy (elastic energy) and from the flux of the alignment. Some applications are discussed. In particular, the Leslie and Frank coefficients of the nematic phase are expressed in terms of the equilibrium alignment order parameter and coefficients which are meaningful in both phases
Vibrational Analysis of SnCl4N and SnBr4N
Authors: Sengodan V. , Srinivasacharya K. G. 
Published: February 2015

Abstract
The kinetic constants method is applied to evaluate a fresh set of force constants in case of SnCl4N and SnBr4N, using recent vibrational frequencies. Certain simplifying considerations involving molecular dynamics are made use of in solving the secular equation. The calculated kinetic and force constants are utilised to evaluate other molecular constants, namely mean amplitudes of vibration, Coriolis coupling constants and centrifugal distortion constants. The calculated mean amplitudes of vibration of the Sn-Br bond (SnBr4N) are within the range of the available experimental values (SnBr4)
Zur Bestimmung der optischen Konstanten stark absorbierender Substanzen mit kleinen Probenabmessungen
Authors: Petersenn Alexander v. , Schuster Hans-Uwe 
Published: February 2015

Abstract
To determine the optical constants of small samples a method described by Avery is suitable insofar as it is not necessary to know the absolute value of the reflected intensity of light. The problem of beam-drift during the rotation of the polarizer is solved with a modified experimental arrangement. A computer program for the evaluation of experimental results is outlined. The optical constants of gold as taken from a crystal 0.2 mm in diameter have been measured to check the accuracy of the system
Unimolecular Decomposition of F2SO3- Calculation by Reduced Kassel Integral in Factorized Form
Authors: Jubert Alicia H. 
Published: February 2015

Abstract
The unimolecular decomposition of fluorine fluorosulfonate at 374.2; 384.2 and 394.2 K, is calculated by means of the Reduced Kassel Integral in Factorized Form, an important method developed by J. Troe. The results are compared with those obtained by the RRKM method and experimental work
Lifetime and Hyperfineinteraction in 1P1 States with Nuclear Spin I =1/2
Authors: Liening H. 
Published: February 2015

Abstract
In evaluating the hfs coupling constant A from levelcrossing signals in excited J = 1 states with 7=1/2 where the hfs splitting is smaller than the radiation width, an independent determi­ nation of the lifetime of the state under study is essential. This is demonstrated in the 6s7p 1Pi-state of171 Yb(7 = 1/2). The results are: r(7p *Pi) = 8.9(3) nsec and |^(7p !Pi) | =9(2) MHz.
Influence of Adsorption upon Sound Attenuation in a Tube *
Authors: Križan Peter , Kuščer Ivan 
Published: February 2015

Abstract
flu e n c e o f A d s o r p tio n u p o n S o u n d A t te n u a tio n in a T u b e * Sound waves propagating in a tube filled with gas are attenuated because of absorption in bulk, because of viscothermal effects, and possibly because the gas is adsorbed upon the wall. The latter effect is shown to depend upon a thermal relaxation time, the near-equilibrium desorption rate, and a phenomenological coefficient containing the sticking probability. In case of multilayer adsorption, especially upon metals, this data could be deduced from measurements of sound attenuation. An early experiment by Maurer is discussed in this light.
Electron Spin Resonance of Manganese Nitrate in Diethylacetamide-Water Solution
Authors: Kleinmann V. , Stockhausen M. 
Published: February 2015

Abstract
le c tro n S p in R e s o n a n c e o f M a n g a n e se N i t r a t e in D ie th y la c e ta m id e -W a te r S o lu tio n At small water concentrations, ESR spectra at room temperature exhibit distinguishable con­ tributions which are ascribed to the following ionic species: (I) a small fraction of residual manga­ nese ions with mixed amide-water solvation, (II) amide solvated ions (having altered hyperfine splitting and gr-factor due to nitrate in an outer coordination sphere, so that they may be con­ sidered loose ion pairs), (III) tight ion pair species. Presumably, (II) and (III) are not well defined "chemical" species but constituents of fluctuating aggregations.
Zur theoretischen Interpretation der Anisotropie der 13C-NMR-chemischen Verschiebungen des Ethylens und Benzens auf halbempirischer Grundlage
Authors: Radeglia R. 
Published: February 2015

Abstract
u r th e o re tis c h e n I n te r p r e ta t io n d e r A n is o tr o p ie d e r 13C -N M R -c h e m is d ie n V e rs c h ie b u n g e n des E th y le n s u n d B en zen s a u f h a lb e m p iris c h e r G r u n d la g e On the Semiempirical Theoretical Interpretation of the Anisotropy of 13C n.m.r. Chemical Shifts of Ethylene and Benzene The paramagnetic contribution of the 13C screening constants and their anisotropics are cal­ culated by using localized orbitals and the CNDO/2 method in the molecular orbital description. A comparison of the average energy method for calculating of shielding tensors with the sum-over-states method is performed. It is concluded that the average excitation energy is higher for the screening perpendicular to the molecular plane.
HFS-Measurements in the 4d95p 1P1
0-and 3D1
0 -States of 105Pd (I=5/2)
Authors: Baumann M. , Lauenstein M. , Liening H. 
Published: February 2015

Abstract
The hfs of the 4d95p 1P1
0 -and 3D1
0 -states of 105Pd(I = 5/2) has been investigated by level-crossing spec­ troscopy. From the measurements we get the following hfs coupling constants: A (3D1
0) = - 302 (6) MHz and A (1P1
0) = -220 (6) MHz.
Relaxation and Backscattering of Light Ions in a Semi-Infinite Medium
Authors: Behnel J. , Ecker G. , Riemann K.-U. 
Published: February 2015

Abstract
Relaxation and backscattering of light ions of moderate energy ( ≲ 1 keV) in solid walls are investigated applying the normal Boltzmann equation to a semi-infinite medium, thereby satisfying the exact boundary conditions at the wall surface. Since momentum and energy relax on different scales, Boltzmann's equation is solved in a two scale procedure, treating momentum and energy relaxation separately. Matching the two regions self-consistently yields the ion distribution function and with that macroscopic quantities, e.g. the range distribution and the spectral reflexion coefficient. The application of the method is demonstrated for a simple test model with constant nuclear scattering cross section and no electronic losses.
Electron Diffraction Investigation of the Molecular Structure of Trifluoromethanesulphonic acid (triflic acid)
Authors: Schultz György , Hargittai Istvan , Seip Ragnhild 
Published: February 2015

Abstract
The molecular geometry of triflic acid is characterized by the following bond lengths (rg) and bond angles from an electron diffraction study: S-C 183.3±0.5, F-C 133.2 ±0.2, S=O 141.8±0.2, S-O 155.8±0.3 pm, S-C-F 110.3 ±0.3, F-C-F 108.6 ±0.3, C-S=O 105.4±1.1, C-S-O 102.3 ±2.3, O-S= O 109.9±0.7, and O=S=O 122.0 ±1.3°. The heavy-atom-skeleton is staggered with respect to the rotation about the S-C bond with an estimated barrier of rotation of 15 kJ mol-1.
The Influence of Ni on the NMR-properties of 209Bi in Liquid Bi-Ni Alloys
Authors: Ploumbidis D. , Bucklisch R. 
Published: February 2015

Abstract
We present detailed experimental results concerning the temperature and concentration dependence of the 209 Bi-Knight shift and the NMR linewidth in liquid Bi-Ni. The measurements are carried out in an external magnetic field of about 39 KG over the concentration range (0-35) at.-% Ni at temperatures from 400 K to 1300 K. According to our experimental results there are no localized magnetic moments in the liquid Bi-Ni system. The experimental results are discussed in the framework of theories on metallic alloys.
Mass Spectrometric Investigation of Aliphatic Aldehydes
Authors: El-Sherbini Th. M. , Allam S. H. , Migahed M. D. , Dawoud A. M. 
Published: February 2015

Abstract
The mass spectra of C2 to C7 n-alkanals have been measured using a double focusing mass spectrometer. The various reaction mechanisms by which the fragment ions are formed have been elucidated and discussed. Two reactions, the β-cleavage with rearrangement and the y-cleavage reactions lead, respectively, to [C2H4O]+ and [C3H5O]+ ions with significant intensities in butyraldehyde and higher n-alkanals.
The electron energy distribution difference (EDD) method together with a computer programme have been used for evaluating ionization efficiency curves for the molecular ions. The ionization potentials obtained by this method show good agreement with those obtained from other electron impact and photoionization experiments.
X-Ray Diffraction on Electrolyte Solutions in the Low Angle Range
Authors: Pálinkás G. , Kalman E. 
Published: February 2015

Abstract
Aqueous cobalt, nickel, zinc, cadmium and aluminium-chloride, -nitrate, -sulphate and PhAsCl solutions at 25 °C were studied by small angle X-ray diffraction. The scattered intensities of chloride, nitrate and CdSO4 solutions show the so-called "prepeak". The concentration dependence of the peak positions is discussed.
Production of Microcrystallinc Zinc Sulphide at Low Temperatures
Authors: Dafinova R. , Kynev K. 
Published: February 2015

Abstract
The conditions for obtaining zinc sulphide through slow crystallization from a solution with a low concentration of zinc and sulphide ions are investigated in this paper. Electron microscopic studies reveal a tenfold growth of the sulphide crystals as compared to those obtained by the usual precipitation process of passing hydrogen sulphide through a zinc salt solution. X-ray analysis shows their sphalerite structure. The luminophore which was prepared by "cold" activation was of a low intensity and had an emission maximum in the long wave range.
A PPP-investigation of Structural Isomerism in Infinite Polyenes
Authors: Karadakov Peter , Castaño Obis 
Published: February 2015

Abstract
It is shown on the grounds of a semiempirical PPP-treatment that for the equidistant eistrans infinite polyene two types of Hartree-Fock solutions are possible-one yielding a cis-transoid and the other a trans-cisoid distribution of nearest-neighbour bond-orders. Relaxing the nuclear framework according to bond-order magnitudes for the bond-alternation wave (BAW) in the equidistant all-trans polyene, resp. for the two solutions for the equidistant cis-trans polyene mentioned above and using repeatedly the Coulson-Golebiewski formula, realistic self-consistent values of bond lengths have been obtained. The calculated energy differences between the investigated isomers are small, predicting almost equal probabilities. The expressions for the PPPwavefunctions are presented in analytical form suitable for further applications. Long-range Coulomb interactions have been accounted for up to convergence of the groundstate energies.
Weak Mixing in a Quantum System
Authors: Kozak J. J. , Rössler O. E. 
Published: February 2015

Abstract
An analytical solution to the Wigner-Weisskopf problem (an excited two-level atom in inter-action with a radiation field), obtained for both finite-and infinite-length boxes, is re-examined in terms of the qualitative behavior implied. As the equations and the plots of the solutions show, there is a major difference between the behavior of the finite system (with discrete spec-trum) and that obtaining in the large-system limit. In the first case, a pulse-shaped wave "travels down the line" and comes back (and is sent off again) many times, completely "losing its shape" in the process (and subsequently re-gaining it on a much longer time scale infinitely often, due to the presence of a Poincare recurrence). In the large-system limit, on the other hand, a delta-impulse-like wave travels down the line only once (in finite time), and there is also no loss of shape upon its return after infinite time. Thus, there is no longer any even temporary "smearing out" of the initially sharply localized energy, and hence no "mixing" in the intuitive sense of the word. Nonetheless a dense spectrum is found (similarly as in the distribution theoretical case of an isolated delta-impulse in an infinite domain), and hence weak mixing in the sense of Lebowitz. The contradiction can be resolved at the expense of having to abandon some symmetry: by assuming the atom adjacent to two cavities of incommensurate lengths. Then the infinite system limit is unchanged (no return in finite time), but the transition is characterized by intuitive mixing of increasing effectiveness.
Imperfect Bifurcations and Spatial Structures in Dissipative Systems
Authors: Hlavacek V. , Janssen R. , Rompay P. Van 
Published: February 2015

Abstract
One-dimensional reaction-diffusion equations associated with the trimolecular model of Prigogine and Lefever ("Brusselator") are analyzed. A physical description of possibilities of keeping con-centrations of initial components constant is discussed. It is shown that the problem considering diffusion of initial components gives rise to an imperfect bifurcation problem. The diffusion equa-tions have been solved numerically by a continuation procedure for the fixed and zero flux boundary conditions. The analysis indicates that the models including diffusion of all reacting components do not admit an occurence of trivial solutions. These models, as a result, also exclude the pos-sibility of primary bifurcations. The models which consider diffusion of the initial components suppress the number of possible solutions of governing equations. These models may also predict both symmetric and asymmetric states. Apparently this type of models is more suitable for predic-tion of patterns of spatial organization in growth. Since the number of possible profiles is strongly reduced this principle may lead to a more deterministic way of an evolution process. Symmetric profiles occuring on an isola cannot be reached by an evolution process unless a large perturbation is imposed on the system.
Wavelength Dependent and Adiabatic Photochemistry of Endoperoxides of Aromatic Hydrocarbons
Authors: Schmidt R. , Drews W. , Brauer H.-D. 
Published: February 2015

Abstract
The photochemical cleavage of the endoperoxides of anthradichromene and benzodixanthene into the parent hydrocarbon and oxygen is shown to be an adiabatic photoreaction originating from an upper excited singlet state. This photochemical behaviour is described by a theory for the photochemistry of endoperoxides developed by Kearns and Khan.
Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro- und Submillimeter-Wellen. I. Primäre Amine / Intramolecular Dipole Reorientation and Dielectric Loss of Microwaves and, Submillimetrewaves in Diluted Solution I. Primary Amines
Authors: Klages G. , Wieczorek E. 
Published: February 2015

Abstract
The dielectric loss of very diluted solutions of four aromatic and three aliphatic amines in three non polar aliphatic solvents at 20 °C has been measured. The wave numbers cover 0.1 to 200 cm-1 . It is shown, how to analyse the microwave spectra of the loss factor ε″ in terms of three absorption areas, two of Debye relaxation type and the high frequency one of Lorentz resonance type. To limit the latter at its high frequency side, the extinction coefficient a has been used to determine and separate the lowest molecular resonances. From the analysis, dispersion steps and the components of the dipole moment due to the three absorption regions are calculated. Comparison with the so called optical dispersion step insures within the limits of experimental error that the absorption due to orientation of the permanent dipole moment is covered by the measured band. The long wave region belongs to the rotation of the molecules, the two others to intramolecular reorientation. In aromatic amines not all molecules of the sample are able to invert their NH2 group, but slower orientation by hindered inversion happens. On the other hand, in aliphatic amines the group is rotating and the high frequency region may be due to Foley absorption.
Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro- und Submillimeterwellen. IL Sekundäre und tertiäre Amine / Intramolecular Dipole Reorientation and Dielectric Loss of Microwaves and Submillimetrewaves in Diluted Solution II. Secondary and Tertiary Amines
Authors: Klages G. , Wieczorek E. 
Published: February 2015

Abstract
Supplementary to a preceding investigation on primary amines, the dielectric loss increments of three aromatic dimethylamino compounds, diphenylamine, N-methyldiphenylamine and triphenylamine, and of dicyclohexylamine have been measured in very diluted solutions at 20 °C. The loss data resulting from 0.1 up to 250 cm-1 are now covering the complete absorption region due to reorientation of the permanent molecular dipole, especially that part based on inversion. To resolve this part, the absorption curves are analysed in terms of three areas using the same method as done for primary amines. By this the dipole components assigned to the special reorientation processes may be discerned and discussed. So the dipole component of the dimethylamino group which reorientates by intramolecular motion is smaller than that of the amino group. The occurrence of an inversion process is demonstrated, but the molecular dipole component governing it also may reorient more slowly as the result of a hindered inversion. The additional reorientation of a mesomeric moment by twisting of the phenyl groups is suggested in triphenylamine and in the diphenyl compounds. The aliphatic dicyclohexylamine only shows a Poley absorption area, increased perhaps by intramolecular libration.
The Chemla Effect in the Internal Mobilities of (Li-NH 4 )N0 3 Melts
Authors: Okada Isao 
Published: February 2015

Abstract
Internal mobility ratios in melts of the system (Li-NH4)NO3 were measured with the Klemm method. Densities and electric conductivities of this system were also measured. From these data the internal mobilities bLi and bNH⁴ were calculated. On account of the inevitable thermal decomposition of NH4NO3 the range of temperatures and concentrations was limited. In these the mobility of NH4
+ is considerably greater than that of Li+. In contrast to other binary nitrate systems, the isotherms of the internal mobility of the larger cation distinctly decrease with a decrease of its concentration, in which the fact that NH4NO3, whose cation is moderately light though large in size, melts at relatively low temperature is reflected. The isotherms of bLi and bNH⁴ and the temperature dependence are discussed on the basis of the autor’s interpretation so far presented.
Exzeßenthalpien und Solvatationsverhalten der Systeme LiBr/Methanol, ZnBr2/Methanol und LiBr/ZnBr2/Methanol
Authors: Christahl M. , Thönnissen J. 
Published: February 2015

Abstract
For the binary systems Li Br/methanol and Zn Br 2/methanol as well as for the ternary system Li Br/Zn Br 2/methanol the integral enthalpies of mixing are experimentally determined. The mixing of Li Br and methanol is more exothermic than in the case of Zn Br 2. The excess enthalpy is largest for the ternary system. From the mathematical approximation of experimental data the differential enthalpies of solution and of dilution are obtained. In the discussion it is concluded that in diluted solutions the salts are surrounded by a strongly coordinated inner solvation sphere (coordination number N = 4) and a less coordinated outer solvation sphere (N = 6) resulting in a total solvation number of N = 10.
Superfluorescence from Chemically Pumped Iodine Molecules
Authors: Stephan-Rossbach K. H. , Comes F. J. 
Published: February 2015

Abstract
Stimulated emission from chemically formed excited iodine molecules has been observed. The emission originates from the vibrational state ν′ = 55 of I2(B 3 II). The excited molecules are produced by a three body recombination reaction.