摘要:

The titration curve of poly-L-glutamic acid was studied in connection with the helix-coil transformation.

ISSN:0026-8976    

DOI:10.1080/00268976000100441

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The analysis of the ‘wiggle-beat’ patterns produced by rapid passage through simple NMR multiplets is modified and extended to permit analysis of beats from multiplets where adjacent signals are not equally separated and where the intensities are not necessarily in the ratio of the appropriate binomial coefficients. The simple example of mono-silane-d1(SiH3D) is illustrated:JHD= 0·427 ± 0·003 c/s. Allowance is also made for the finite time of passage through the signal and the usefulness of this demonstrated by analysing the beat pattern from the asymmetric spectrum of a mixture of SiH3D and SiH4. In this way the SiH4-SiH3D chemical shift is estimated to be 0·0080 ± 0·0005 p.p.m., the SiH4resonance being to low field.

ISSN:0026-8976    

DOI:10.1080/00268976000100451

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

At temperatures sufficiently high to produce an appreciable pressure of 9, 10-diphenylanthracene, perylene or pyrene, the quantum yield of fluorescence is found to be independent of vapour pressure. The negative temperature coefficient of self-quenching in anthracene vapour is explained in terms of the dissociation of an excited dimer which is also responsible for delayed fluorescence.

ISSN:0026-8976    

DOI:10.1080/00268976000100461

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

A simple unit is described which can be incorporated in a high resolution nuclear magnetic resonance spectrometer to remove the spin coupling between two groups of hydrogen nuclei in the same molecule. Applied to the molecule of propionaldehyde, the method considerably simplifies the analysis of the high resolution spectrum measured at 60 Mc/s.

ISSN:0026-8976    

DOI:10.1080/00268976000100471

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

By means of second-order perturbation theory and the use of the closure approximation, a simple closed formula is developed for the dispersion energy of interaction between spherical systems or molecules with axial symmetry. This expression contains an explicit two-electron correlation term. Agreement with experiment is most encouraging and is ascribed to the inclusion of this correlation term.

ISSN:0026-8976    

DOI:10.1080/00268976000100481

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The effect of bond length changes on ground and excited state energies is examined. The results are applied to aniline.

ISSN:0026-8976    

DOI:10.1080/00268976000100491

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The use ofV,WandXcoefficients in calculations of matrix elements is shown. General formulae for all two-electron spin-orbit coupling matrices in an octahedral strong-field coupling scheme are deduced. The parametrization of the electrostatic energy in ligand field theory is discussed and the number of parameters required is given in various cases. The configurationf2in an octahedral strong-field scheme is treated in some detail and reasons for the anomalously low paramagnetism of PuF6are exposed, largely in contradiction to earlier views [13, 14]. Finally it is shown that expressions involving recoupling matrix elements, which occur in a scheme for calculating matrix elements of one-electron operators given by Tanabe and Kamimura [3], are proportional toWandXcoefficients, thus considerably extending the scope of the latter work.

ISSN:0026-8976    

DOI:10.1080/00268976000100501

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The basis of the theory of electric dipole intensities in centrosymmetric ions is critically examined. It is shown that the physical assumptions of one current version [3, 4, 5] of this theory are mathematically inconsistent and the necessary revision of the theory is given. It is also pointed out that excitations from odd parity filled shells into thedshell should give a significant, and usually negative, contribution to the intensities.

ISSN:0026-8976    

DOI:10.1080/00268976000100511

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The proton resonance spectrum of meta-dinitrobenzene is reported and analysed at 60 Mc/s as an AB2X spectrum and at 29·9200 Mc/s as an AB2C spectrum.

ISSN:0026-8976    

DOI:10.1080/00268976000100521

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor

摘要:

The polarizability properties ofπelectron systems are treated by the self-consistent field method, as modified by Pople for application to conjugated molecules. An analytical treatment of theπelectron configuration of substituted hydrocarbons deduces certain universal symmetry properties of this method, and contains the Hückel treatment of inductive substituents as a simplified special case. Whereas the usual Hückel theory derives results by approximate perturbation methods, the treatment given here is formally exact. In a later section s.c.f. polarizability coefficients, as calculated on an Elliott 402 digital computer, are given for benzene, naphthalene, anthracene and phenanthrene, and the predictions of chemical properties are shown to be in better agreement with experiment than predictions derived from Hückel theory.

ISSN:0026-8976    

DOI:10.1080/00268976000100531

出版商:Taylor & Francis Group    

年代:1960

数据来源: Taylor