| | 83 | Author
| Isao Okada, Ryuzo Takagi, Kazutaka Kawamura | Requires cookie* | | | Title
| A Molecular Dynamics Simulation of Molten (Li-Rb)Cl Implying the Chemla Effect of Mobilities  | | | | Abstract
| A new transport property, the self-exchange velocity (SEV) of neighbouring unlike ions, has been evaluated from molecular dynamics simulations of molten LiCl, RbCl and LiRbCl2 at 1100 K and the mixture at 750 K. From the increase of the SEV's in the order Rb + (pure salt)<Li+ (mixture) < Rb + (mixture) < Li+(pure salt), it is conjectured that there is a strong correlation between the SEV's and the internal mobilities. An interpretation of the Chemla effect in its depen-dence on temperature is given. The pair correlation functions and the self-diffusion coefficients are also calculated and discussed. | | | |
Reference
| Z. Naturforsch. 35a, 493—499 (1980); received March 25 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0493.pdf | | | | Identifier
| ZNA-1980-35a-0493 | | | | Volume
| 35 | |
| 84 | Author
| V. Massarotti, G. Flor, A. Marini, R. Riccardi | Requires cookie* | | | Title
| Molybdates Solid State Synthesis: The MgO—MoO a System | | | | Abstract
| The formation reaction of Mg2Mo30n from MgO (single crystal) and M0O3 (pellet) has been investigated in the temperature range 873—973 K. Supported by an analysis of the transport properties a mechanism is proposed involving a uni-directional transport of Mo 6+ via V"0 and of oxygen via gas phase. The transport properties of MgMo04 (the other intermediate compound in the system MgO —M0O3) were also studied and the results were found to agree with the mechanism observed in a previous work on the basis of kinetic and structural considerations. | | | |
Reference
| Z. Naturforsch. 35a, 500—502 (1980); received March 20 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0500.pdf | | | | Identifier
| ZNA-1980-35a-0500 | | | | Volume
| 35 | |
| 85 | Author
| E.Georg Meyer, Bernhard Nickel | Requires cookie* | | | Title
| Diffusion Coefficients of Aromatic Hydrocarbons in Their Lowest Triplet State: Anthracene in Hexane, Octane, Hexadecane, Perfluorohexane, and Methylcyclohexane; Pyrene and 9,10-Di- phenylanthracene in Hexane | | | | Abstract
| An experimental method is described which allows the determination of the diffusion coeffi-cient D of an aromatic hydrocarbon in its lowest and metastable triplet state T\ with an absolute accuracy of ±5%. D was determined at 25 °C. With anthracene the temperature-dependence of D was measured from 0°C to 60°C in hexane and from 20°C to 89°C in hexadecane; it was found to be in good but not perfect agreement with the Stokes-Einstein equation. With the investigated systems, D of molecules in T\ is estimated to be at most 10% smaller than D of molecules in the ground state. No evidence for the formation of triplet excimers was found. Some applications of the method are proposed, and in this connection some questions concerning the kinetics of diffusion-controlled reactions of molecules in T\ and the existence of triplet excimers are discussed. | | | |
Reference
| Z. Naturforsch. 35a, 503—520 (1980); received January 16 1980 | | | |
Published
| 1980 | | | |
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| | | | | TEI-XML for
| default:Reihe_A/35/ZNA-1980-35a-0503.pdf | | | | Identifier
| ZNA-1980-35a-0503 | | | | Volume
| 35 | |
| 86 | Author
| Fernando Bernardi, Andrea Bottoni, Arturo Ballaglia, Giuseppe Distefano, Alessandro Dondoni | Requires cookie* | | | Title
| Selectivity in Ketenimine Cycloadditions. Photoelectron Hel Spectra of Ketenimines | | | | Abstract
| The first few bands in the photoelectron (Hel) spectra of ketenimines R 1 R 2 C—C=NR 3 (R 1 , R 2 =H, CH3, C5H6, CHo=CH; R 3 = alkyl or aryl group) are assigned to the correspond-ing molecular orbitals. The assignment is based on SCF-MO calculations made at three different levels (CNDO/2, ab-initio ST0-3C and 4-31G) coupled with perturbational molecular orbital analyses. The jz-orbitals of the unsaturated substituents are found to interact with one of the two perpendicular ^-electron systems of the)>0=C=N— residue, the critical factor being the position of attack of the substituent. The relevance of these results on the site selectivity observed in cycloaddition reactions of these species is discussed. | | | |
Reference
| Z. Naturforsch. 35a, 521—525 (1980); received March 15 1980 | | | |
Published
| 1980 | | | |
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| | | | | TEI-XML for
| default:Reihe_A/35/ZNA-1980-35a-0521.pdf | | | | Identifier
| ZNA-1980-35a-0521 | | | | Volume
| 35 | |
| 87 | Author
| H. G. Busse, B. H. Havsteen | Requires cookie* | | | Title
| Network Structure of a System coded by Groups | | | | Abstract
| A system may be characterized by its dynamics as well as by its structure. Several kinds of schematic drawings have been proposed to represent the structure of a system. Here, the representation of the structure by free groups is discussed. Free groups are an abstract mathe-matical tool, which permits the systematic treatment of a structure. The suggestion is exempli-fied by its application to a chemical kinetic model. The structure of the model is given (coded) by a linear sequence of symbols. The interaction of the environment with the structure (muta-tion) and the relation between structure and systemic boundaries (finiteness) are treated. The concept probably also applies to biological systems. Also, context-free languages could be used as alternate representations of system structures. | | | |
Reference
| Z. Naturforsch. 35a, 526—530 (1980); received February 15 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0526.pdf | | | | Identifier
| ZNA-1980-35a-0526 | | | | Volume
| 35 | |
| 88 | Author
| N. Miekeley, P.C S Fernandes | Requires cookie* | | | Title
| Zur Diffusionskinetik in Ionenaustauscherharzen Selbst-und Austauschdiffusion von Alkali-und Erdalkaliionen | | | | Abstract
| The Diffusion Kinetic in Ionic Resin Exchangers. Self-and Exchange-Diffusion of Alcaliions Heterogeneous isotope exchange rates of Na~, Ca + , Ba 2+ and Sr 2+ in mono-and biionic resin exchangers (Merck I) have been measured under conditions where diffusion is rate determining. For the self-diffusion of Na + , Ba 2+ and Sr 2+ linear Dtjr 2 — /(J)-curves are obtained. Cs-isotope exchange shows non-ideal diffusion kinetics. In mixed Ba-exchangers the self-diffusion coeffi-cients of Ba 2i ~ and Sr 2 f depend on the ionic composition of the exchanger phase. Ion exchange rates have been measured for Ba/Sr 2+ -exchange and its reversal. Computed curves are presented using Helfferich's theory of ion exchange and an extended treatment with activity correction terms and concentration dependent self-diffusion coefficients. Computed and experimental curves are discussed. | | | |
Reference
| Z. Naturforsch. 35a, 531—530 (1980); eingegangen am 8. Oktober 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0531.pdf | | | | Identifier
| ZNA-1980-35a-0531 | | | | Volume
| 35 | |
| 89 | Author
| P. Klaeboe, M. Moneeb, E. Törneng, H. Hopf, I. Böhm, B. N. Cyvin, S. J. Cyvin | Requires cookie* | | | Title
| The Conformation and Vibrational Spectra of l-Cyano-3-Butyne | | | | Abstract
| The infrared spectra of l-cyano-3-butyne were recorded in the region 4000 —50 cm -1 in the vapour and liquid states, as an amorphous and as two different crystalline solids at 90 K. In ad-dition the compound was studied as a high pressure crystalline solid at ambient temperature. Raman spectra of the liquid, including polarization measurements, and of the amorphous and the two crystalline solids at 90 K, were obtained. The spectra revealed the existence of two conformers, anti (Cs) and gauche (Cx symmetry) in the vapour, liquid and in the amorphous solid. When annealed to ca. 140 K a metastable crystal containing one conformer (probably the gauche) was formed, when annealed to ca. 190 K a stable crystal was obtained having the other conformer (probably the anti). The latter conformer was present in the high pressure crystal. Very accurate spectral data for each conformer were collected from the two crystalline solids, making complete assignments for the anti and gauche conformers feasible. The assignments were checked by a normal coordinate analysis. A simple diagonal force field was derived in which the same force constants were employed for the anti and gauche conformers. The mean amplitudes of vibration were calculated for both conformers. | | | |
Reference
| Z. Naturforsch. 35a, 537—548 (1980); received March 6 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0537.pdf | | | | Identifier
| ZNA-1980-35a-0537 | | | | Volume
| 35 | |
| 90 | Author
| V. M. Valyashko, M. Buback, E. U. Franck | Requires cookie* | | | Title
| Infrared Absorption of Concentrated Aqueous LiCl Solutions to High Pressures and Temperatures | | | | Abstract
| The infrared absorption of the O-D stretching fundamental of HDO in concentrated aqueous (HDO/HoO) LiCl solutions to a maximum of 40 mole percent salt has been measured. Data for the wavenumber of maximum absorption, i^(max), and for the integrated molar absorptivity B up to pressures and temperatures of 2800 bar and 350 °C, respectively, are reported and discussed. Toward high salt concentrations, the dependence of r(max) on temperature and on LiCl con-centration decreases. The wavenumber data indicate a transition from "water-like" to "melt-like" behaviour at about 12 to 15 mole percent LiCl. | | | |
Reference
| Z. Naturforsch. 35a, 549—555 (1980); received April 1 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0549.pdf | | | | Identifier
| ZNA-1980-35a-0549 | | | | Volume
| 35 | |
| 91 | Author
| Miloš Marek, Milan Kubíček | Requires cookie* | | | Title
| Patterns of Spatial Organization in Growth | | | | Abstract
| Patterns of spatial concentration profiles arising in one-dimensional reaction-diffusion systems in the course of variations of the characteristic dimension of the system (growth) are analyzed. The spatial profiles established and their changes depend on the character of the steady state pattern dependence on length. If the families of solutions (spatial profiles) arising at L — nL\*, nL<i* form closed curves, and a slow (quasistationary) linear or exponential increase of the char-acteristic dimension is considered, then subsequently more complex patterns of spatial concen-tration profiles appear regularly in a reproducible way. The system keeps every established pattern for a fixed interval of time which depends on the rate of growth. Implications for two different interpretations of the morphogen gradient formation in the models of embryogenesis are discused. | | | |
Reference
| Z. Naturforsch. 35a, 556—563 (1980); received September 20 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0556.pdf | | | | Identifier
| ZNA-1980-35a-0556 | | | | Volume
| 35 | |
| 93 | Author
| F. Wahl | Requires cookie* | | | Title
| Eine kanonische Transformation als Lösungsvorschlag für eine Funktionalgleichung | | | | Abstract
| Starting with a functional equation of the New Tamm-Dancoff procedure for electronic states of defects in solids we describe an attempt to transform this equation. The aim is to extract a one-particle equation as a projection which is a good approximation for the case of a defect. The transformation usetii s a simple approach to more general canonical transformations leading to inequivalent representations of the many-body problem. It is compared with the elimination procedure given in a first paper [1] which treated the manj-electron problem occuring with the storage of hydrogen in metals. | | | |
Reference
| Z. Naturforsch. 35a, 567—578 (1980); eingegangen am 31. März 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0567.pdf | | | | Identifier
| ZNA-1980-35a-0567 | | | | Volume
| 35 | |
| 94 | Author
| Johannes Kirsch, Berndt Müller, Walter Greiner | Requires cookie* | | | Title
| Unified Theory of Electrons and Photons in Heavy Ion Collisions | | | | Abstract
| We present a unified formulation of the interaction of electrons with the electromagnetic field in heavy ion collisions, based on quantized interacting fields. This reduces the effort in treating many-electron systems substantially, as compared with the usual ^-matrix theory. Both formalisms are shown to be equivalent. The simplification achieved by our new approach is demonstrated in detail for the example of quasi-molecular radiation. | | | |
Reference
| Z. Naturforsch. 35a, 579—589 (1980); received March 11 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0579.pdf | | | | Identifier
| ZNA-1980-35a-0579 | | | | Volume
| 35 | |
| 96 | Author
| P. Hochmann, G. L. Findley, S. P. Mcglynn, P. Mcglynn, S. Chattopadhyay, P. Hochmann, H.-T Wang | Requires cookie* | | | Title
| Molecular Rydberg Transitions. X Correlation Algorithms for Rydberg Term Values | | | | Abstract
| The empirical linear correlations of Rydberg term values [S., are discussed in a first-order perturbation-theoretic format. In the second-order, quadratic dependencies are expected. The theoretical development assumes that the gross features of interatomic and intermolecular Rydberg term value variations can be discerned using a one-electron model; that a molecule XS, X being the Rydberg chromophore and S the substituent, can be partitioned so that the affairs of the optical electron are dominated by its interactions with the chromophoric segment; and that the charge distributions, whether of X or S, can be expanded in ways which permit evaluation of the effects of small variations in either X or S on Rydberg term values. The development is restricted to Class 1 molecules: Mo-lecules which possess a common S and variable X, but where all X must be of similar electronic structure e.g., X = F, Cl, Br, I). A variety of correlative algorithms is discussed, and the inter-group transferability of parameters is elaborated in terms of the properties of "average chromo-phores". | | | |
Reference
| Z. Naturforsch. 35a, 595—609 (1980); received November 28 1979 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0595.pdf | | | | Identifier
| ZNA-1980-35a-0595 | | | | Volume
| 35 | |
| 98 | Author
| E. Ehrmann-Falkenau, A. Wagendristel | Requires cookie* | | | Title
| The Influence of Grain Boundary Migration on the Diffusion Behaviour of Thin Films | | | | Abstract
| Simultaneous grain boundary-, surface-and lattice diffusion in hypothetical thin film couples of miscible components was computer simulated. On this basis the diffusion into fixed and moving grain boundaries is discussed with respect to the determination of diffusivities by depth profiling methods. The data evaluated from the synthesised depth profiles according to Whipple-Le Claire as well as to Gilmer and Farrell were compared with the diffusivities used for the computation. Agreement was found for systems with a fixed grain boundary network. Moving grain boundaries, however, may cause errors of an order of magnitude towards lower grain boundary diffusivities. | | | |
Reference
| Z. Naturforsch. 35a, 613—618 (1980); received March 28 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0613.pdf | | | | Identifier
| ZNA-1980-35a-0613 | | | | Volume
| 35 | |
| 100 | Author
| F. F. Hanna, K. N. Abdel-Nour, J. E. Risk | Requires cookie* | | | Title
| Dipole Moment and Dielectric Relaxation of Some Aromatic Ethylenes and Butadienes | | | | Abstract
| The dipole moment of 1,1-bis-p-chlorophenylethylene, 1,1-bis-p-bromophenylethylene, 1,1-bis-p-methoxy, -ethoxy, -isopropoxy-phenyl-ethylene, 1,1,4,4-tetrakis-p-methoxy, -ethoxy, isopropoxy-phenylbuta-l,3dienes was measured and compared with the calculated value. The mesomeric moment was estimated and found to decrease in the case of the ethylenes with the increase in volume of the substituted group. For the butadienes, the mesomeric moments compensate each other. Investigations of the dielectric relaxation times of the ethylenes showed that the orientation of the -OCH3 group in the 1,1-bis-p-methoxy-phenylethylene is hindered to a large extent. The orien-tation of the -OC2H5 and -OC3H7 groups in the corresponding molecules are restricted due to steric hindrance. | | | |
Reference
| Z. Naturforsch. 35a, 623—627 (1980); received May 5 1980 | | | |
Published
| 1980 | | | |
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| default:Reihe_A/35/ZNA-1980-35a-0623.pdf | | | | Identifier
| ZNA-1980-35a-0623 | | | | Volume
| 35 | |
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