摘要:

The change in the structure factor as a measure of the disappearance of order during quenching from the solid to the melt in a two-dimensional system is studied by two methods, one traditional and the other newly proposed here. The new method, which considers the maximum peak of the mean configuration instead of the mean maximum peak over the configurations, is found to be more accurate in the location and height of the peak, and found to give a slightly smaller non-equilibrium relaxation time midway.

ISSN:0026-8976    

DOI:10.1080/00268979600100111

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The problem of sedimentation equilibrium is treated within the integral equation formalism of inhomogeneous fluids using the Ornstein-Zernike approach, and using the Percus-Yevick closure, to describe sterically stabilized and charged colloidal suspensions contained in pores of different size. The calculated density profiles exhibit pronounced oscillations near the bottom, showing layering, and, for large pores, a non-oscillatory tail, in agreement with Monte Carlo simulations. For small pores, the particle distribution includes the appearance of layers for small separations. In the case of bidispersions, the computation shows that for large pores there is non-monotonic behaviour by one of the components, owing to competition between excluded volume and gravity. A similar effect is shown in monocomponent systems if the particles interact via a Yukawa-type potential.

ISSN:0026-8976    

DOI:10.1080/00268979600100121

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The FTIR spectrum of monoisotopic H370GeD around 6100 cm-1was recorded with a resolution of about 0·012 cm-1. A perpendicular-type band,v0(E) = 6129·441 cm-1, is observed, which is unperturbed forK′ ⩽ 1>2. Its rotational analysis reveals, in addition to rovibrationalrandqresonance effects within the E vibrational state, a strong rovibrational α resonance perturbation by an almost degenerate perturber of A1symmetry,v0= 6129·434 cm-1. Owing to intensity perturbations the parallel component is very weak in spite of a transition moment ratioM(E)/M(A1) of about -2. The rovibrational energy level pattern is indicative of local mode behaviour of thev(GeH)= 3 state, in which Coriolis effects are almost absent and simple arithmetic relations between vibration-rotation parameters fulfilled as expected. This gives rise to an excited state energy level pattern almost consistent with that of an asymmetric rotor.

ISSN:0026-8976    

DOI:10.1080/00268979600100131

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A torsionally flexible molecule is represented as a spherocylinder that undergoes fluctuations in either its cap radius (breathing mode) or its cylinder length (stretching mode). The free energy of the flexible spherocylinder is calculated in analogy with earlier work based on density functional and Onsager theories of the isotropic-nematic transition. In the Landau-de Gennes limit of this theory, there are three order parameters, corresponding to the molecular alignment, molecular shape and an alignment-shape coupling. The effect of flexibility on the primary order parameter is addressed as well as the effect of alignment on molecular shape.

ISSN:0026-8976    

DOI:10.1080/00268979600100141

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The liquid-gas phase diagram for the dimerizing hard-core Yukawa fluid is calculated. The model consists of the one-site hard-sphere dimerizing model of Wertheim with an additional Yukawa attraction included into the nonassociating part of the interaction. The thermodynamic properties of the model are obtained from the analytical solution of the associative mean spherical approximation. Predictions of the theory are consistent with qualitative trends in the behaviour of the phase equilibrium of associating liquids.

ISSN:0026-8976    

DOI:10.1080/00268979600100151

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Amphiphilic molecules, such as the carboxylic acids and their salts, organic esters and alcohols, lipids, phospholipids and some other organic compounds have a tendency to form a wide variety of complex supramolecular structures. These could be liquid crystalline layers, micelles, vesicles and different exotic multilayer patterns. Such properties are essential for many biological processes and industrial applications. To describe these phenomena a theoretical model is proposed based on the weighted-density functional approach. Attention is focused on ordering in surfactant films of amphiphilic compounds at the liquid-vapour and liquid-liquid interfaces. These compounds contain one or several polar groups and a hydrophobic tail, which are responsible for the different kinds of liquid-expanded-liquid-condensed and layering phase transitions in the films. Such transitions involve essential changes in the conformational or orientational states of the surfactant molecules depending on their chemical composition and stiffness. Much experimental data for π - A isotherms are consistent with the theoretical results.

ISSN:0026-8976    

DOI:10.1080/00268979600100161

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor