ISSN:0005-9021    

DOI:10.1002/bbpc.19820860602

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

年代:1982

数据来源: WILEY

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860603

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe photoreactivity of multimolecular Langmuir‐Blodgett layers is studied with optical absorption spectroscopy. Whereas the polymerization of monomeric layers can be initiated by UV‐irradiation only, irradiation of partially polymerized layers with visible light up to λ ≤ 500 nm leads to a continuation of the reaction. The maximal polymer yield obtained with UV‐ and visible light irradiation is the same. The action spectra of the chain growth of partially polymerized layers and of the photoconductivity correspond to each other. A new mechanism of the chain growth is

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860604

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

年代:1982

数据来源: WILEY

摘要:

AbstractMultilayers of amphiphilic diacetylene fatty acids are prepared following the method of Langmuir and Blodgett. The photopolymerization of the diacetylene units can be sensitized for visible light by surface active cyanine dyes embedded in the multilayers. Using optical spectroscopy a high polymer yield is found. The yield is independent of the spectral range of the absorption and the concentration of the dyes, respectively, in the range between 0.02 and 3 mole percent. ‐ The quantum yield of the sensitized photopolymerization is low: the dye molecule must absorb about 1000 photons to sensitize the reaction of one monomer molecule. The fluorescence of the dyes is already quenched at low conversion. The origin is an energy‐ and electron transfer to the oligomer ch

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860605

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

年代:1982

数据来源: WILEY

摘要:

AbstractQuantitative experimental results are reported for the photo‐decomposition of octafluorocyclobutane under irradiation with intense, mono‐chromatic light from a pulsed TEA‐CO2‐laser in the range of thev21fundamental near 963 cm−1. The IR‐photochemical rate coefficient is found to befor irradiation with P 8 at 954.6 cm−1, close to the optimum frequency. It is shown that the intensity dependence is linear to a good approximation by comparing irradiation with intense self‐mode‐locked pulse trains and smooth single mode pulses of low peak intensity, generated by means of an intracavity absorber. Results on the frequency dependence and upon the influence of inert gas pressure in the IR‐photochemistry of C4F8are reported. The experimental results are found to compare well with theoretical predictions based on a Pauli equation treatment and simple models for the rate

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860606

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

年代:1982

数据来源: WILEY

摘要:

AbstractCorrelation functions ϕ(t) and correlation times were obtained by Fourier transformation of the degenerate fundamental bandsv24andv21of liquid cyclohexane. Reorientational correlation functions were calculated based on the Kubo line shape theory in order to extract the contribution of vibrational relaxation. Dephasing caused by short range interactions is a possible mechanism for vibrational relaxation at least forv21

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860607

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

年代:1982

数据来源: WILEY

摘要:

AbstractA 90 MHz proton NMR determination of the activation and thermodynamic parameters of the Schlenk equilibrium of 2‐methylpropylmagnesium bromide in tetrahydrofuran is reported. The entropy of activation is consistent with bimolecular reactions of unassociated species proceeding through a transition state resembling a mixed‐bridge dimer. The quantitative data confirm accepted concepts of the solvation states of the species involved. — Association equilibria were explored in order to ensure that they were insignificant under the conditions of the kinetic measurements on the Schlenk equilibria. — The association of di‐2‐methylpropylmagnesium is strongly concentration‐dependent but almost temperature‐independent. The exchange rate is too slow to be measured by NMR methods and much slower than the Schlenk equilibrium. The associates are either cyclic or cluster compounds, or, if linear, have an average degree of polymerization of 10. — The field positions of the resonances of RMgBr and R2Mg reverse a

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860608

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

年代:1982

数据来源: WILEY

摘要:

AbstractThe structural properties of the Independent‐Molecular‐Interaction‐Sites (IMIS) reference fluid for homonuclear hard dumbbell systems are investigated in the Percus‐Yevick and in the Hypernetted‐Chain approximation, respectively. The interaction‐site pair distribution functions obtained from the IMIS model are compared with the “exact” results from a Monte‐Carlo study and with predictions from the RISM theory. The calculations presented in this publication are suggesting, that the IMIS model represents a close approximation to the site‐site pair correlations

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860609

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

年代:1982

数据来源: WILEY

摘要:

AbstractCharge transfer from n‐butyl chloride radical cations (BuCl+) to 11 solutes (S) (alkanes, alkenes, aromatics, and amines) was studied by pulse radiolysis. Using a mechanism proposed for radiation‐induced ionic processes in liquid n‐butyl chloride the rate constants of the reactionwere determined. At gas phase ionization potential differences ΔI= (IBuCl‐Is) smaller than 1.5 eV the rate constants increased rapidly with increasing ΔIand reached for larger ΔInearly constant values of about 1010dm3mol−1s−1. The dependence of the rate constants on the ionization potential differenceskvs. ΔIis explained in terms of a two‐step process consisting of migration of solvent cations and electron transfer from the solute molecule to the solvent cation. The probability of the last step was calculated using the Franck‐Condon principle. In the framework of a simplified model taking into account vibrational stretching and deformation modes of the reactants and solvent modes in thermally averaged form a reasonable fit of thekvs. ΔIbe

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860610

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

年代:1982

数据来源: WILEY

摘要:

AbstractA series of 4‐alkylamido‐2‐hydroxybenzoic acids, containing 8–16 carbon atoms in the alkylamido group, has been synthetized and characterized. Surface tension measurements on aqueous solutions have been used to estimate the critical micellar concentrations and the area per molecule at the liquid‐air interface. Light scattering measurements allowed to calculate the aggregation number and the hydrodynamic radius of the

ISSN:0005-9021    

DOI:10.1002/bbpc.19820860611

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

年代:1982

数据来源: WILEY