摘要:

Derivations are given for several expressions relating density expansion coefficients of the net radial distribution function, the direct correlation function, and the x-ray scattering function. To the first order in density, non-additivity effects are included.

ISSN:0026-8976    

DOI:10.1080/00268976700100651

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The possibility of introducing triplet potentials into a theory of fluids at the level of the first order HNC and P.Y. theories is discussed. If we do so we obtain extended theories which, at low densities, give the third virial coefficient correctly. More generally, we are led to an effective pair potential which is a linear function of the density of the fluid. Reference is made to the relevant experimental work of Mikolaj and Pings.

ISSN:0026-8976    

DOI:10.1080/00268976700100661

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The introduction of triplet potentials into the Percus-Yevick theory of fluids is made by a method similar to that of Rushbrooke and Silbert, but based upon a different classification of the graphs in the expansion of the correlation function. Their method is suitable for the hyper-netted chain theory but, it is suggested, the method used here is more appropriate for the Percus-Yevick theory. The results differ, and are compared.

ISSN:0026-8976    

DOI:10.1080/00268976700100671

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

ISSN:0026-8976    

DOI:10.1080/00268976700100681

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Cis and trans proton coupling constants in ethylene have been calculated using the variational procedure and valence bond formalism. The problem is treated as an eight-electron eight-orbital one, with six orbitals belonging to the σ framework and two to the π. σ-π exchange is implicitly included.

ISSN:0026-8976    

DOI:10.1080/00268976700100691

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The general formulation necessary for the calculation of the root-mean-square amplitudes of vibration of square planar molecules is presented within the framework of Morino's method. The root-mean-square amplitudes of vibration of the Xe-F, the adjacent F…F, and the trans F…F interatomic distances in XeF4have been theoretically estimated to be 0·0465å, 0·1101å, and 0·0633å, respectively at 298°K. While the experimental value of the last of these has not yet been ascertained, the first two compare favourably with the reported values of 0·05åand 0·10å. Furthermore, the root-mean-square amplitudes of vibration of the Xe-F and F…F interatomic distances in XeF2were calculated to be 0·0469åand 0·0638årespectively at 298°K. The striking resemblance of these values with those of XeF4suggests strongly that the bonding in both molecules must be similar.

ISSN:0026-8976    

DOI:10.1080/00268976700100701

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The three types of fluid solution E.S.R. spectra generated by the mononegative ions of triphenylene could be assigned satisfactorily to the free anion and two different ion pairs, respectively. The available experimental data suggest that one of these ion pairs is solvent separated, whereas the other is a contact ion pair. These two different ion pairs are in rapid equilibrium with each other. The thermodynamic quantities characterizing this equilibrium have been derived using the observed temperature dependence of the alkali splitting.

ISSN:0026-8976    

DOI:10.1080/00268976700100711

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The E.S.R. spectra of the radical anions of pyridine, 4-picoline, 3,5-lutidine, 2,6-lutidine, pyrazine, pyrimidine, pyridine N-oxide, 4-picoline N-oxide and 2,6-lutidine N-oxide have been observed in liquid ammonia. The data for pyridine, pyrazine and pyrimidine can be combined to evaluateQNN= +27·3,QCNN= -1·7 andQH= -24·5 gauss independently of molecular orbital spin densities. Good agreement is found for the observed coupling constants for the N-heterocyclics and McLachlan's theory with methyl group coupling consistent with both Levy's hyperconjugation equations and withQCH3eff.= 25·7 gauss. The coupling constants for the N-oxides are in satisfactory agreement with an arbitrary set of molecular orbital parameters.

ISSN:0026-8976    

DOI:10.1080/00268976700100721

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

The thermal conductivity data of the Ne-Ar, Ne-Kr, Ar-Xe and Kr-Xe systems are reported as a function of composition and at temperatures 40°, 65° and 90°c. Similar results are also presented for the ternary systems Kr-Ar-Ne, Xe-Kr-Ar and a quaternary system Xe-Kr-Ar-Ne. A conductivity cell of the thick hot-wire type is used. The thermal conductivity values for the binary mixtures are compared with those obtained from rigorous theory and such procedures as approximate, semi-theoretical, empirical, linear mixing, reciprocal mixing, combination of linear and reciprocal mixing and quadratic equations. A similar study is also made for ternary and quaternary mixtures and some interesting conclusions are drawn concerning the relative appropriateness of different methods for computing thermal conductivity of multi-component gas mixtures.

ISSN:0026-8976    

DOI:10.1080/00268976700100731

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor

摘要:

Para-hydrogen chemical shifts in a series of monosubstituted benzene derivatives have been shown to depend linearly on theπ-electron density variations on the adjacent carbon atom calculated by a non-empirical Hückel LCAO method. Attention is drawn to the fact that important modifications of ring-current intensity occur when a substituent is introduced in the benzene molecule.

ISSN:0026-8976    

DOI:10.1080/00268976700100741

出版商:Taylor & Francis Group    

年代:1967

数据来源: Taylor