摘要:

Ab initioSCF calculations have been performed in order to support previous experimental work on ions in solution and to give further insight into the nature of the different contributions to the solvation shifts of core electron binding energies and Auger energies. As a by-product of the calculations excellent values are obtained for solvation energies of Na+(H2O)n(n= 1-6) clusters.

ISSN:0026-8976    

DOI:10.1080/00268978500100911

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The collision induced far infrared spectrum of N2is evaluated by molecular dynamics using a model of quadrupole induced dipoles. The results for two high density, low temperature states (ϱ = 742 Amag,T= 81 K and ϱ = 610 Amag,T= 91 K) are compared with new measurements. The spectral line shapes show a faster decay at high frequency (v> 90 cm-1) than those given by experiment. The integrated absorption coefficient is shown to result from almost complete cancellation between two-, three-, and four-body contributions. The effect of the polarizability anisotropy on the integrated absorption and line shape is examined.

ISSN:0026-8976    

DOI:10.1080/00268978500100921

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Assuming the monomer wavefunction in the form of a CI expansion in terms of orbitals of the whole dimer, the expression for the Heitler-London interaction energy is analyzed and implemented in the calculations of the He dimer. It is proved that the ‘zeroth-order exchange’ term Δ vanishes if the CI expansion is a full one. If the CI wavefunctions are complete up ton-fold excitations the contributions to Δ can be related only to excitations higher thann-fold ones. If the gaussian orbitals are used the problem of a gaussian asymptotic behaviour of the CI ansatz appears to be effectively circumvented.

ISSN:0026-8976    

DOI:10.1080/00268978500100931

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

LongitudinalT1Zand quadrupolarT1Q, and transverseT2relaxation times of deuterium in all the hydrogen sites of deuterated hexahexyloxytriphenylene (THE6), were measured over the whole stability range of the discotic mesophase. Two isotopic species were used for the measurements, i.e. THE6 deuterated in the aromatic sites, ar d THE6 perdeuterated in the aliphatic chains. Several experimental techniques were used in order to obtain the relaxation times, including the Jeener-Broekaert, selective inversion, and quadrupole echo pulse sequences. Measurements were mainly performed on samples in which the liquid crystalline domains were distributed in a plane with the directors perpendicular to the field direction. Experiments were also made on a single domain sample with the director parallel to the field direction. The experimental results were used to obtain several spectral densitiesJp(pω) for both the parallel and perpendicular orientations, of all the deuterium sites in the THE6 molecule. The results are discussed in the light of existing theories.

ISSN:0026-8976    

DOI:10.1080/00268978500100941

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We study the behaviour in viscoelastic fluids of the high-frequency viscosity factorC(n(ωm)). This factor depends upon the numbern(ωm) of exponential decay terms needed to describe the observed relaxation behaviour in a frequency range 0 to ωm. Quite generallyn(ωm) increases with increasing ωmand decreasing temperature (T).Ccan be interpreted as the ratio η(0)fast/η(0) where η(0) is the zero frequency viscosity, and η(0)fastis that component of the viscosity that is associated with rapidly decaying relaxation processes, i.e. with processes that decay in times shorter than ωm-1. AsTdecreases, more relaxation processes become slow thereby accounting for a decrease inC; at sufficiently lowT, the only fast processes are the very fast (molecular) ones that vary little withTand are called the ‘bare processes’. Thus at lowT,Cis small and varies as η-1. At highT, 1 —Ccan be associated with the shear-orientation parameterR, and at lowTthe quantityCη(0)k2/ρ can be associated with thek-dependent part of the shear wave relaxation frequency.

ISSN:0026-8976    

DOI:10.1080/00268978500100951

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

New values for double mode-mode and triple flux molecular equilibrium correlations are presented. The relevance of these results for hydrodynamics is then discussed. It is found that the divergence of Burnett coefficients has only a formal meaning.

ISSN:0026-8976    

DOI:10.1080/00268978500100961

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Rovibrational Raman spectra of low density H2S gas have been measured with the aim of extracting the components of the polarizability tensor derivatives with respect to the normal modes of the molecule. Absolute values are obtained by comparison with the intensity of the symmetric stretching polarizedQ-branch available in the literature.

ISSN:0026-8976    

DOI:10.1080/00268978500100971

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

A density functional-variational version of the Ramakrishnan-Yussouff theory of freezing is used to reconsider the problem of the hard sphere transition. This calculation differs from previous ones in that the solid density and the lattice constant are included asindependentvariational parameters. Besides giving an unambiguous method for determining the lattice constant of the solid this method allows the computation of the average density of defects in the solid. In addition, we use real, rather than Fourier, space techniques in solving the resulting equations. We argue that real space techniques are numerically more accurate for the narrow distributions found by these methods. Our results for the densities of the coexisting solid and liquid phases are very close to those given by molecular dynamics studies. The width of the solid density peaks is too small as is the case with previous calculations. The average density of defects has the correct sign but is much too large (ρD⋍ -0·1) for a realistic solid.

ISSN:0026-8976    

DOI:10.1080/00268978500100981

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor