ISSN:0005-9021    

DOI:10.1002/bbpc.19770810502

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractErste Nachbarcluster werden zur Interpretation des Metall K‐ und L2.3‐, des Nichtmetall K‐Emissionsspektrums und des Valenzröntgen‐photoelektronenspektrums von CrN herangezogen. Ein Vergleich der berechneten Intensitäten mit den experimentellen Spektren wir

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810503

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe self‐diffusion coefficients and radial pair‐distribution functions for a 256 particle system of the liquid mixture CH4/CF4over a concentration range of 0.2–0.8 mole fraction methane and a temperature range of 100 – 160 K were calculated by molecular dynamics calculations (MDC) with Lennard‐Jones potentials. The calculations included the region of the critical solution point, which has been experimentally determined to be at 0.57 mole fraction methane and 94.5 K. — The MDC results indicate the critical region to lie around 0.55 mole fraction methane and 100 – 115 K. Fluctuations of the mean‐square‐displacement of particles and changes in the pair‐distribution functions of the model system are in good agreement with the experimentally derived picture of a microscopic phase separation near

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810504

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractProton magnetic relaxation rates of the methyl, the methylene and the OH group of propionic acid and of ethanol in the mixture with CCl4have been measured. These compounds were partly labled by deuterons and the corresponding deuteron magnetic relaxation rates were also measured. From all these data the proton intra‐ and intermolecular relaxation rates were determined together with proton relaxation rates caused by another proton containing group. The latter results then yielded intermolecular closest distances of approach between the various groups and from these orientation dependent model pair distribution functions in three dimensions have been constructed. It has been shown that the propionic acid pair configurations in CCl4resemble somewhat to those found in the solvent water whereas for ethanol the behaviour in the two solvents is markedly differen

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810505

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe magnetic1H‐relaxation rate in aqueous solutions of LiCl, NaCl, RbCl, CsCl, and KI was measured in order to evaluate the nuclear magnetic proton‐ion relaxation contribution using the isotopic dilution technique. Furthermore, the temperature dependence of these relaxation rates was examined. It turned out that for Rb+, Cs+, and I−the proton‐ion relaxation rate consists of two parts: an intermolecular spin‐rotation contribution and a magnetic dipole‐dipole contribution. The first one increases and the second one decreases with increasing temperature. — From the dipole‐dipole rate the proton ion distances were computed using suitable ion‐proton model pair distr

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810506

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe reaction of dichlorocarbene with ethylene produces chemically activated 1,1‐dichlorocyclopropane which isomerizes in a primary reaction to give 2,3‐dichloropropene. Dichlorocarbene is generated by the thermal decomposition of CCl3‐ SiX3(X = F, Cl) at 531 K. The rate constantskaiof isomerization and decomposition of all chemically activated compounds reported in this work and the preceding publication were calculated by RRKM‐theory and compared with the experimental results. Agreement was obtained if an excess energyEifor CCl2was introduced.Ei= 9 kJ/mol for CCl3‐SiCl3as CCl2source andEi= 22kJ/mol for CCl3‐SiF3as CCl2source. CCl2was thermalized by addition of helium and nitrogen; the collision efficiencies of these gases were

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810507

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe growth and dissolution kinetics of a crystal suspension during periodic temperature changes was studied by a thermometric method. The plot of the (overall) flux density versus solution supersaturation exhibits a hysteresis: The growth rate at the beginning of the growth period was found to be considerably higher than the corresponding growth rate at the end of the growth period at the same supersaturation, while the dissolution is, on the contrary, slower at the beginning of the dissolution period than at its end at the same undersaturation. A qualitative discussion of the results is presented.

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810508

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractSilylradikale reagieren nach zwei Reaktionswegen ab:1Rekombination zu einem hoch schwingungsangeregten Disilan2Disproportionierung zu Silylen und Silan.Das Silylen verschwindet in einer sehr schnellen Einschubreaktion, ebenfalls unter Disilanbildung. ‐ Die beiden Reaktionswege (1) und (2) können durch Isotopenmarkierung unterschieden werden. Das nach (1) gebildete Disilan kann entweder unimolekular unter Bildung von Silylen und Silan zerfallen oder durch Stöße stabilisiert werden. Das Verhältnis von Disproportionierungs‐ zu Rekombinationsprodukten ist daher druckabhängig. Extrapolation auf unendlichen Druck ergibt für das Verhältnis Disproportionierung zu Rekombination den Wert 0,7 ± 0,1. Die quantitative Analyse der deuterierten Disilane erfolgte mit Hilfe der Photoionisations‐Massen

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810509

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractThe reduction of the excited charge‐transfer state of tris(2,2'‐bipyridine)‐ruthenium(II), Ru(bipy)32+by organic donors (D) in methanol was studied by laser photolysis technique. The reduction follows the general schema:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm D} + ^* {\rm Ru}({\rm bipy})\mathop {\rm 3}\limits^{{\rm 2 + }} \to {\rm D}^{\rm + } + {\rm Ru(bipy})\mathop 3\limits^ + .} & {(1)} \\ \end{array} $$\end{document}The rate of reduction is diffusion controlled for all donors except diphenylamine for which a rate constant of 2.5 · 107M−1s−1was obtained. The reduction potential of *Ru(bipy)32+was determined experimentally to lie close to the thermodynamic limit of 0.85 V. ‐ Reaction (1) and subsequent dark reactions were examined in detail for D = phenothiazine (PTH). For this donor the efficiency of electron transfer was found to be 0.6 ± 0.2. The spectrum of Ru(bipy)3+obtained from these studies shows a maximum at λ = 510 nm with an extinction coefficient of 1.8 · 104M−1cm−1. Ru(bipy)3+was found to decay exponentially with a time constant of 1.1 · 105s−1. At higher PTH concentrations, this reaction competes with electron transfer from Ru(bipy)3+to PTH for which a rate constant of 3.4

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810510

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY

摘要:

AbstractEs wird eine neue Meßapparatur beschrieben, mit der der stationäre Zustand der Thermodiffusion in Salzschmelzen untersucht werden kann. Mit dieser Zelle gelingt es zum ersten Mal, zuverlässige Endwerte der Thermokraft der betrachteten Thermoketten zu bestimmen. Untersucht werden die Systeme LiNO3+ AgNO3und NaNO3+ AgNO3im Temperaturbereich von 220°C bis 340°C in Abhängigkeit von der Zusammensetzung. Der Zeitverlauf der EMK der Thermokette bis zum Erreichen des stationären Zustandes der Thermodiffusion wird diskutiert, und die Überführungsentropien der Silberionen in beiden Salzschmelzen werden als Funktion der Zusammensetzung b

ISSN:0005-9021    

DOI:10.1002/bbpc.19770810511

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1977

数据来源: WILEY