摘要:

Es wurden die hochaufgelösten N.M.R.-Spektren der tautomeren Gemische von 2-Picolylisopropyl- und 2-Picolylphenylketon exakt analysiert. Außer den Linien der Keto- und Enolformen konnten keine zusätzlichen Linien, die einer weiteren tautomeren Form zuzuschreiben sind, beobachtet werden.

ISSN:0026-8976    

DOI:10.1080/00268976600100791

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

The electronic energy levels of diphenyl have been calculated by a Pariser, Parr and Pople method for angles between the two benzene rings of 0°, 45° and 90°. All singly but no doubly excited states have been considered. The results are compared with the electronic spectra of diphenyl and its sterically hindered derivatives and with the circular dichroism spectra of optically active diphenyl derivatives.

ISSN:0026-8976    

DOI:10.1080/00268976600100801

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

On montre que pour des raisons de symétrie électronique, les fragments OH+(3Σ−) ne peuvent pas être obtenus directement à partir des ions H2O+formés par arrachement d'un électron. Pourtant ces fragments sont observés en grande quantité dans les spectres de masse. On montre que ces ions sont formés par prédissociation: les états2B2et2A1de l'ion moléculaire sont prédissociés par un état4A2,4A″. La formation de S+et SH+dans H2S s'explique de la même façon.

ISSN:0026-8976    

DOI:10.1080/00268976600100811

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

The hypochromic effect in DNA is discussed using a non-retarded version of earlier work of the author based on the response function. Single particle or incoherent excitation is distinguished from coherent Frenkel excition response and a model is presented in which different transition dipoles are coupled differently to their neighbours. This is justified by the extreme degree of asymmetry present in the DNA polymer so that dipole lattice sums depend on the relative orientations of the dipole and the polymer rod axis. It is found that the obsorved hypochromic effect without shift in frequency of the lowest frequency absolution maximum can only be accounted for if the lowest transition dipole yields a small value for the dipole lattice sum.

ISSN:0026-8976    

DOI:10.1080/00268976600100821

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

A N.M.R. study of diamagnetic salts and CoCl2in pure water and in 10 : 1 mole ratio aqueous mixtures of acetone, N,N-dimethylformamide, dimethylsulphoxide, dioxane, ethanol, methanol and N-methylformamide, has been carried out. Water chemical shift displacements indicate that this component extensively solvates most cations. These displacements are correlated with ion charge, entropy, size, and with the water concentration. Evidence for solvation by the organic component was provided by the water results, AlCl3solution studies, and paramagnetic studies. In the AlCl3solutions, in the DMF, DMSO, and NMF-H2O solvent mixtures, separate N.M.R. signals were observed for bulk and complexed organic solvent.

ISSN:0026-8976    

DOI:10.1080/00268976600100831

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

The electron resonance spectra of two ground state triplets have been measured in the isotropic and nematic mesophase ofp-azoxyanisole. The extra transitions observed when the biradicals are in the nematic mesophase are interpreted in terms of an unaveraged zero-field splitting. The nitrogen hyperfine splitting is also found to decrease in the nematic mesophase. The observation of these extra lines in the spectra provides excellent quantitative confirmation for the triplet character of these radicals. The changes in the spectra are satisfactorily accounted for using the swarm model of nematic liquid crystals.

ISSN:0026-8976    

DOI:10.1080/00268976600100841

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

Silver atoms formed by the γ-irradiation of frozen solutions of argentous salts react with excess cations to form a new species which is shown by an analysis of its electron spin resonance to be the dimer Ag2+. The identification is confirmed by using silver enriched in109Ag. The hyperfine andgtensors are discussed in terms of the expected electronic structure of this ion.

ISSN:0026-8976    

DOI:10.1080/00268976600100851

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

The use of Wigner and Eisenbud's R-matrix theory for molecular collisions is discussed. A model of harmonic oscillators is proposed; in this model the activated complex has one negative normal frequency.

ISSN:0026-8976    

DOI:10.1080/00268976600100861

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

The fluorine chemical shifts in halogen-substituted benzenes have been calculated and compared with experimental values. It is found that the co-called van der Waals shift makes a substantial contribution to the total chemical shift particularly when the substituent is ortho to the fluorine nucleus. This van der Waals shift is strongly dependent on the molecular geometry so that fluorine chemical shifts could be a possible source of information about overcrowding in molecules.

ISSN:0026-8976    

DOI:10.1080/00268976600100871

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor

摘要:

Using recently published analytical SCF wave functions for xenon, the one-electron molecular orbital energies of xenon tetrafluoride have been re-determined in the Wolfsberg-Helmholz semi-empirical approximation. Unlike similar previous investigations, the present study takes into consideration ligand-ligand overlap, and uses the recently proposed reciprocal mean for the semi-empirical evaluation of the resonance integrals. The outcome of the study fits remarkably well with the observed electronic transitions in the faru.v.spectrum of XeF4.

ISSN:0026-8976    

DOI:10.1080/00268976600100881

出版商:Taylor & Francis Group    

年代:1966

数据来源: Taylor