摘要:

The electronic spectra of the benzazulenes and benzologue-tropylium cations have been interpreted on the basis of a perimeter model, using a modified form of the Pople-Pariser-Parr method. The agreement between theory and experiment is satisfactory, and much better than when the same method is applied to benzenoid hydrocarbons. A critical discussion is given of the use of the perimeter model for classifying the states of these compounds.

ISSN:0026-8976    

DOI:10.1080/00268976300100011

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

This report begins with a short review of approximative methods which have been used for the calculation of polycentric integrals. Against this background a new method is proposed which replaces the product of two atomic orbitals by the sum of two squares of approximate atomic orbitals. The parameters and localization of these orbitals are so chosen that the approximative expression has the same monopole, dipole, quadrupole and octupole moments as the approximated one. The investigation of the accuracy of approximative methods hitherto used as well as of the new approximative method is carried out for twelve types of integrals. It is shown that in most cases the proposed method provides much better results than the methods hitherto applied.

ISSN:0026-8976    

DOI:10.1080/00268976300100021

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

In order to determine the absolute signs of the zero field splittings of the photo-excited triplet state of dilute naphthalene in durene, we have made electron spin resonance measurements at 4·2°kand 1·65°k, where Boltzmann populations differ sufficiently to cause measurable intensity effects. Our results confirm the theoretical predictions:Zis negative;XandYare positive.

ISSN:0026-8976    

DOI:10.1080/00268976300100031

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The optical electronegativityxoptbehaves in essentially the same way in the 3d group as in the 4d and 5d hexahalides though the variation differs in details. Thus, the tetrahedral complexes have considerably higherxoptthan the corresponding octahedral compounds. The slope ofxoptversus the numberqof electrons in the partly filled shell is compared for the 3d and 4f groups, and is smaller than in the gaseous ions as are also the differences ofxoptbetween the oxidation numbers +3 and +2 for the sameq.

ISSN:0026-8976    

DOI:10.1080/00268976300100041

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

ISSN:0026-8976    

DOI:10.1080/00268976300100051

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Rigorous and approximate expressions are derived for the first and second approximations to the thermal diffusion factor of a binary gas mixture where the lighter component is in trace. Numerical calculations have been performed for the He-Xe system (He in trace) as a function of temperature.

ISSN:0026-8976    

DOI:10.1080/00268976300100061

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

It is shown that Kubo's statistical formula for the general transport coefficient of a classical system may be simply obtained by considering the result of a retarded measurement on a canonical non-equilibrium ensemble.

ISSN:0026-8976    

DOI:10.1080/00268976300100071

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

Explicit expressions are obtained for the limiting forms at low and high temperatures of the third virial coefficient of a gas composed of molecules with Lennard-Jones (n, ½n) potentials.

ISSN:0026-8976    

DOI:10.1080/00268976300100081

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

A direct method is given for the calculation of bond orders in a conjugated system. The method is based on the simple Hückel approximation.

ISSN:0026-8976    

DOI:10.1080/00268976300100091

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor

摘要:

The high-resolution N.M.R. spectra of a series of bicyclo [2.2.1] heptanols are discussed. Three unusual features are observed: (a) relatively large4J's; (b) unequalJendo-endo's andJexo-exo's; and (c) unusual magnetic shieldings.

ISSN:0026-8976    

DOI:10.1080/00268976300100101

出版商:Taylor & Francis Group    

年代:1963

数据来源: Taylor