摘要:

AbstractTo study the structure breaking effect in aqueous electrolyte solutions (also termed negative hydration), a series of molecular dynamics simulation runs has been carried out. An originally uncharged, nonpolar spherical solute particle (“Xenon”) is charged step by step fromg1= 0.0etoq1= +0.67e, + 1.0eandq1= +2.0e(eis the positive elementary charge). At zero charge the occurrence of hydrophobic hydration is observed. The surroundings of the divalent cation also shows marked structuring: the normal “positive” ionic hydration. In an intermediate region of charge (atq1= 1.0e) negative hydration is detected, which proves to be a state of minimum order. Structural changes are discussed by using pair and three particle correlation functions. Hydration energies, binding energies and pair interaction energy distributions are determined. The microdynamics is studied by observing the reorientational motion and the self diffusion behaviour of the water molecules in different regions. A zone of increased mobility is located in the vicinity of the ion, which may include the innermost hydration shell. Additionally a system comprising a negatively hydrated anion has also been

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850112

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn nonpolar solvents p‐diethylaminobenzoic acid ethyl ester presents multiple fluorescence. The considerable temperature and viscosity dependence of the fluorescence quantum yields as well as solvatochromic effects on the long wavelength fluorescenceFAmake evident that the multiple fluorescence is to be traced back to the formation of a highly polar TICT (Twisted Intramolecular Charge Transfer) stat

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850113

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe contact shifts of13C NMR signals in four aliphatic hydrocarbons in the presence of 2,2,6,6‐tetramethylpiperidine nitroxide radical were determined and explained by collisional interactions. Earlier results for ethers are compared and the origin of the contact shifts is propose

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850114

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe rate of the gas‐phase reaction of NH2radicals with O3was studied in the temperature range 250–358 K, and over the pressure range 4–20 mbar.\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{*{20}c} {{\rm NH}_{\rm 2} {\rm + O}_{\rm 3} \to {\rm products}{\rm .}} & {(1)} \\ \end{array} $$\end{document}The kinetics of the reaction was followed in a discharge‐flow reactor by measuring the decay of [NH2] by laser‐induced fluorescence. The rate coefficient can be expressed as:\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm k}_{\rm 1} {\rm (}T{\rm ) = (1}{\rm .21} \pm {\rm 0}{\rm .07)} \cdot {\rm 10}^{{\rm 12}} {\rm exp( - 5}{\rm .9 } \pm {\rm 0}{\rm .4) kJ mol}^{{\rm - 1}} {\rm /RT) cm}^{\rm 3} {\rm mol}^{{\rm - 1}} {\rm s}^{{\rm - 1}} \cdot $$\end{document}No significant dependence ofk1on pressure was observed. A numerical analysis of the [NH2] profiles suggests that the metathesis reaction to form NH2O and O2is a plausible initial step, and that the NH2O radical can react further with O3to regenerate NH

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850115

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe influence of amino substituents on the excited π‐π* singlet states of phenazine is investigated by absorption, fluorescence, and polarization spectroscopy at 77 K and by PPP‐SCF‐CI calculations including all single and double excitations from the SCF ground state. The Coulomb interaction of the free electron pair of the amino groups with the π‐electrons of phenazine is shown to be responsible, essentially, for the drastic changes in the observed electron

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850116

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

年代:1981

数据来源: WILEY

摘要:

AbstractSolid‐liquid equilibrium data for (i) o‐phenylenediamine‐β‐naphthol, (ii) resorcinol‐o‐phenylenediamine, (iii) o‐phenylenediamine‐α‐naphthol, and (iv) picric acid‐catechol systems, showing congruent melting points, have been recorded. The 1:1 addition compounds formed in these systems form eutectics with either of the components. The linear velocity of crystallization and heat of fusion for the addition compounds and the eutectics have been measured. Microstructural studies indicate that the addition compounds have a structure similar to that of the pure components, whereas the eutectics have fibrous, feather‐like, spherulitic and lamellar structures. The effect of impurities on microstructures has also been discussed. Diffusion coefficient measurements in lamellar eutectics show that Jackson‐Hunt theory of eutectic growth, based on a diffusion model, is applicable. Excess thermodynamic functions,gE,hE, andSEhave also been

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850117

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

年代:1981

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850118

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

年代:1981

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850119

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

年代:1981

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850121

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

年代:1981

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19810850124

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

年代:1981

数据来源: WILEY