ISSN:0005-9021    

DOI:10.1002/bbpc.19850891002

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

年代:1985

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891003

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

年代:1985

数据来源: WILEY

摘要:

AbstractWe report the formation of the azide anion (N−3) in the gas phase by dissociative electron attachment to benzyl azide in a beam experiment. The electron photodetachment cross section of N−3, generated analogously in an ion cyclotron resonance (ICR) spectrometer has been measured. A threshold of 2.76 ± 0.04 eV was obtained corresponding to the vertical detachment energy in N−3. Ab initio calculations on N−3and N3predict similar geometries for both compounds, indicating that the photodetachment threshold can be equated with the electron affinity of the azide

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891004

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

年代:1985

数据来源: WILEY

摘要:

AbstractCharge transfer from n‐hexadecane radical cations C16H+34to solutes as cycloalkanes, alkenes and aromatics was studied by pulse radiolysis. Using ion‐pair kinetics the rate constantsksof the electron transfer reactionswere determined. The electron transfer rate constantsksincrease from low values for slightly exothermic reactions to a limiting value of 9 · 109dm3mol−1s−1when the electron transfer reaction is more exothermic than

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891005

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

年代:1985

数据来源: WILEY

摘要:

AbstractTo study the relation between the rate and the free energy difference of the TT transfer from some aromatic donors (D) to various preferably aromatic acceptors (A) in benzene solution we combined laser photolysis and pulse radiolysis experiments. Transfer rate constantsk1, were determined for DA pairs with differences of the (S0T1) energies ΔE=E(S0T1)D)Abetween −0.2 and 1.4 eV. Ak1versus ΔEplot shows reaction‐controlled values for ΔE≤ 0.2 eV. At higher ΔEthe diffusion‐controlled limit is reached. By analogy with electron and singlet energy transfer thek1vs. ΔErelationship was interpreted as arising from the Franck‐Condon effect in the excess energy acceptance by th

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891006

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

年代:1985

数据来源: WILEY

摘要:

AbstractA continuous‐flow technique has been applied to study the magnetic field effect on the photobleaching quantum yield of thionine in the reaction with aniline in reversed micellar solution and with p‐iodoaniline in methanol. The principle of the experimental technique is to irradiate the solution in a flow‐through cuvette within a magnetic field which is varied in steps and to observe optical density changes in a second cuvette connected to the first one in a flow system. Although the absolute quantum yields of the two photoreactions are below 1%, relative changes due to the magnetic field effect could be resolved with an accuracy of 1%. The observed effects on the permanent photobleaching yield closely follow the effects on the radical yield previously observed in time‐resolved experiments and are explained by the radical pair mechanism and the triplet mechanism, respe

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891007

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

年代:1985

数据来源: WILEY

摘要:

AbstractIn water/dioxane mixtures and aqueous electrolyte solutions the hydration reaction has been studied. The formation of the gem‐diol of aliphatic aldehydes is associated with the binding of 3 water molecules to the carbonyl group, whereas for pyruvic acid 6 or 7 water molecules are involved in this reaction. Rate and equilibrium constants of the reactions have been determined. The hydration equilibria may be used to measure conveniently the local water activity in the aqueous and non‐aqueous regions of micellar solutions and microemulsions. The reaction rate indicates the local proton activity in these syst

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891008

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

年代:1985

数据来源: WILEY

摘要:

AbstractA solution of 30% by weight of the tetramethylammonium salt of the perfluorononanoic acid (TMPFN = C8F17COON(CH3)4) in D2O forms a nematic phase in the temperature range between 32 and 37°C. The nematic phase was aligned and cooled down to 25°C in a magnetic field of 1.63 and 1.26 T. The structure of the aligned sample was studied with small angle neutron scattering (SANS) at different temperatures. In the liquid crystalline phase first and second order Bragg‐peaks were observed. This phase consists mainly of liquid crystals build by sheets of disk‐like TMPFN micelles alternating with layers of D2O. The lattice parameter is around 75 Å at 25°C. An order parameter S near 1 was determined by a thorough analysis of a rocking experiment. Besides the Bragg‐peaks further scattering features were observed: A Debye‐Scherrer like ring probably related to disclike micelles and a ridge related to a unknown aligned structure. The SANS‐pattern was examined in an temperature range betwee

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891009

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

年代:1985

数据来源: WILEY

摘要:

AbstractPhotoelectrochemical behaviours of two kinds of polymorphic form of TiO2, rutile and anatase, prepared by the organometallic chemical vapour deposition from isopropyl titanate have been comparatively studied. Photoelectrochemical characteristics of these TiO2electrodes depend strongly upon the crystal structure and the deposition temperature. Their bandgap energies have been determined to be 3.0 eV and 3.2 eV, respectively, by the analysis of the photocurrent action spectra. The conduction band‐edge and the valence band‐edge of the anatase electrode, which have been estimated from photocurrent‐potential curves, locate at the energy level about 0.1 eV higher and lower, respectively, than those of the rutile elec

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891010

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

年代:1985

数据来源: WILEY

摘要:

AbstractThrough computer control, precipitated manganese(II)‐hydroxide and manganese(II)‐hydroxide/aluminum hydroxide are investigated as positive electrodes for secondary cells in aqueous potassium hydroxide solution with regard to charge capacity and cycling behaviour. Pure Mn(OH)2is oxidizable to MnO1.21, the discharge capacityqdlies between 17.2 and 24.0 in mAh/g; ca. 50 cycles are measured during decreasing discharge capacity. Manganese(II)‐hydroxide/aluminum hydroxide takes up comparatively more charge with better Faraday‐efficiency and can reach the oxidation stage MnO1.48. The determined maximal discharge capacityqdwith 121 mAh/g is also much greater than with Mn(OH)2; with decreasing discharge capacity 60–70 cycles are observed. The electrochemical properties are influenced by thepHvalue of the precipitati

ISSN:0005-9021    

DOI:10.1002/bbpc.19850891011

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

年代:1985

数据来源: WILEY