Магнитные состояния в модели поверхностного димера

For the electrons of surface dimer formed by adsorbed particle and substrate atom effects of the intra- and interatomic Coulomb interactions are taken into account. Two cases are considered: adsorption of magnetic particle on nonmagnetic substrate and adsorption of nonmagnetic particle on magnetic substrate. Analytical expressions for the surface dimer magnetization are obtained for the regimes of weak and strong dimer – substrate coupling

Зависимость электронной структуры графеновой наноленты от концентрации адсорбированных частиц

The effect of the indirect exchange of particles adsorbed on a graphene nanoribbon on the width of the induced energy gap and the effective mass of carriers is studied. Analytical dependences of these characteristics on the concentration of adparticles, the adsorbate–substrate binding energy, and the energy level of the adsorbed particle are obtained.

Surfactants

Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.

Роль кулоновского взаимодействия электронов адсорбата и субстрата: модель поверхностного димера

Coulomb interaction in adsorption system is reduced to the short-range repulsion of the electrons of adsorbed particle and substrate surface atom which are considered as the surface dimer. It is shown that the account of such an interaction leads to the increase of charge transfer between the dimer’s components and decrease of charge transfer between dimer and metallic substrate due to the Fermi level variation.

ORGANOMETALLIC MICELLE COMPRISED OF GOLD MULTIPLY TWINNED PARTICLE AND SELF-ASSEMBLED THIOLS

We have demonstrated the method to stabilize gold particles by using the technique of self-assembled alkanethiol. Au and S peaks of the X-ray spectroscopy show that it consists of Au particle and alkanethiols. The chemical bond between Au and S is confirmed by the NMR spectrum. The typical size of the particle is less than 30 nm, observed by the scanning electron microscope. The predicted structure of the thiol-adsorbed particle is like a micelle, and we have named this particle the organometallic micelle.

Determination of the adsorption film characteristics of alkyltriphenylphosphonium cations from time dependent capacitance measurements

The determination of the adsorbed film characteristics at the interface between methanolic solutions of quaternary phosphonium salts and the Hg electrode is carried out by means of time dependent capacitance measurements. The maximum surface concentration, the area per adsorbed particle and the orientation of methyltriphenyl-, cyclopropyltriphenyl-, and n-butyltriphenylphosphonium cations are derived by two methods, the first of which is free of isotherm assumptions and the second involves an adsorption isotherm obeyed by the system under examination.