Microscopic point of view

From a microscopic point of view, an element is a substance all of whose atoms have the CENGAGENOW... 

The next section is devoted to the analysis of the simplest transport property of ions in solution the conductivity in the limit of infinite dilution. Of course, in non-equilibrium situations, the solvent plays a very crucial role because it is largely responsible for the dissipation taking part in the system for this reason, we need a model which allows the interactions between the ions and the solvent to be discussed. This is a difficult problem which cannot be solved in full generality at the present time. However, if we make the assumption that the ions may be considered as heavy with respect to the solvent molecules, we are confronted with a Brownian motion problem in this case, the theory may be developed completely, both from a macroscopic and from a microscopic point of view. 

From a microscopic point of view of the absorption process, we can assume a simple two energy level quantum system for which N and N are the ground and excited state population densities (the atoms per unit volume in each state). The... 

Coal is an extremely heterogeneous material, both from a macroscopic and microscopic point of view. Correlation of liquefaction reactivity with coal properties is, as a result, inherently difficult and any truly "universal correlations that will be developed will need to be based... 

A logical development of this study will be to consider the microscopic point of view i.e the elementary reactions to build the infinite reverse micelles of the network. Detailed structural information is necessary to undertake a more microscopic approach of the kinetics. The aggregation mechanisif involves hydrogen bonding as clearly demonstrated by an IR spectrocopy study (3 ) and has to be understood. 

Common liquids are optically isotropic, and the solids that physicists seem to like most are cubic and therefore isotropic. As a consequence, treatments of optical properties, particularly from a microscopic point of view, usually favor isotropic matter. Among the host of naturally occurring sohds, however, most are not isotropic. This somewhat complicates both theory and experiment for example, measurements of optical constants must be made with oriented crystals and polarized light. But because of the prevalence of optically anisotropic solids, we are compelled to extend the classical models to embrace this added complexity. 

It has been shown that die BCS theory does lead to die phenomenological equations of London. Pippard and Ginzburg and Landau, and one may therefore state that the basic phenomena of superconductivity are now understood from a microscopic point of view, i.e., in terms of the atomic and electronic structure of solids. It is true, however, that we cannot yet, ub initio, calculate V For a given metal and therefore predict whether it will be superconducting or not. The difficulty here is our ignorance of the exact wave functions to be used in describing the electrons and phonons in a specific metal, and their interactions. However, we believe that the problem is soluble in principle at least. 

The validity of the Stokes relation has also been investigated from the microscopic point of view, and the following surprising result is obtained. Indi-... 

Interest in thermotropic liquid crystals has focussed mainly on macroscopic properties studies relating these properties to the microscopic molecular order are new. Lyotropic liquid crystals, e.g. lipid-water systems, however, are better known from a microscopic point of view. We detail the descriptions of chain flexibility that were obtained from recent DMR experiments on deuterated soap molecules. Models were developed, and most chain deformations appear to result from intramolecular isomeric rotations that are compatible with intermodular steric hindrance. The characteristic times of chain motions can be estimated from earlier proton resonance experiments. There is a possibility of collective motions in the bilayer. The biological relevance of these findings is considered briefly. Recent similar DMR studies of thermotropic liquid crystals also suggest some molecular flexibility. 

From a microscopic point of view, octupole deformation in even-even nuclides is signalled by (r and 0 bands that have the same properties. This implies a ground state rotational band with alternating even and odd parity states, i.e. 0+, 1, 2+,. Such ground state bands have not been found in any nuclides to date. In Fig. 2, we show the results of a microscopic calculation of octupole correlation energies in the 0+ and the 1 states of Ra... 

Whereas the ideal solution model applies over the entire range of concentrations, but only for very similar components, the ideally dilute solution model applies to any solution, but only over a very limited range of concentrations. From a microscopic point of view, the ideally dilute solution holds as long as solute molecules are almost always completely surrounded by solvent molecules and rarely interact with other solute molecules. 

In particularly thorough examples of the traditional physical organic approach, Parker (1969) and Abraham (1974) interpreted solvent effects on Walden inversion reactions by using thermodynamic transfer functions. However, in order to explain the reaction rate decrease upon solvation from a microscopic point of view, quantum mechanical electronic structure calculations must be carried out. Micro-solvated Sn-2 reactions were initially studied in this way, with the CNDO/2 semiempirical molecular orbital (MO) method, by using the supermolecule... 

From the microscopic point of view, again the CO-induced 1 x 2- 1 x 1 structural transformation of the Pt(l 10) surface (as also underlying the mechanism of temporal oscillations) is of crucial importance for the development of facets, as becomes evident from the fact that this effect is restricted to conditions of high stationary CO coverages. Simply speaking, CO adsorption lifts the 1 x 2 reconstruction and simultaneously creates... 

Considering what happens at the molecular level, we note first that the process -does not start until the partition is actually removed, and at that instant the molecules occupy only half the space available to them. In this momentary, initial state the molecules are not randomly distributed over the total volume to which they have access, but are crowded into just half the total volume. In this sense they are more ordered than they are in the final state of uniform distribution throughout the entire volume. Thus, the final state can be regarded as a more random, or less ordered, state than the initial state. From a microscopic point of view we therefore associate an entropy increase with an increase in randomness or a decrease in order at the molecular level. 

Moreover, the PT mechanism, specifically the role played by the water molecules, is not well understood from the microscopic point of view and deserves further analysis. 

The temperature at which the phase transition occurs is called the critical temperature or Tg. Most, but not all, magnetic phase transitions are continuous , sometimes called second order . From a microscopic point of view, such phase transitions follow a scenario in which, upon cooling from high temperature, finite size, spin-correlated, fractal like, clusters develop from the random, paramagnetic state at temperatures above Tg, the so-called critical regime . As T Tg from above, the clusters grow in size until at least one cluster becomes infinite (i.e. it extends, uninterrapted, throughout the sample) in size at Tg. As the temperature decreases more clusters become associated with the infinite cluster until at T = 0 K all spins are completely correlated. 

The stochastic model of ion transport in liquids emphasizes the role of fast-fluctuating forces arising from short (compared to the ion transition time), random interactions with many neighboring particles. Langevin s analysis of this model was reviewed by Buck [126] with a focus on aspects important for macroscopic transport theories, namely those based on the Nernst-Planck equation. However, from a microscopic point of view, application of the Fokker-Planck equation is more fruitful [127]. In particular, only the latter equation can account for local friction anisotropy in the interfacial region, and thereby provide a better understanding of the difference between the solution and interfacial ion transport. 

The transition metal atom has a possibility to possess a magnetic moment in metaUic material, then an investigation of the spin polarization of the cluster from a microscopic point of view is very important in understanding the magnetism of the metallic materials. We try to explain the spin polarization and the magnetic interactions of the cluster in terms of the molecular orbital. For the heavy element in the periodic table whose atomic number is beyond 50, it is mentioned that the relativistic effects become very important even in the valence electronic state. We perform the relativistic DV-Dirac-Slater calculation in addition to the nonrelativistic DV-Xa calculation for the small clusters of the 3d, 4d and 5d transition elements to clarify the importance of the relativistic effects on the valence state especially for the 5d elements. 

New techniques such as laser Raman spectrophotometry, NMR spectroscopy and X-ray and neutron diffraction methods, as well as EXAFS and XANES spectroscopy, provide us tools to observe solution phenomena from the microscopic point of view on the bases of structural chemistry and reaction dynamics. Thus, structural and dynamic studies of solutions have been developed as new streams of solution chemistry. 

Water is one of the most familiar material in our life and is indispensable to all living things. In contrast to its apparently simple molecular structure, water shows many anomalous properties from both macroscopic and microscopic points of view. However, the basic physical property of water, for example the dynamical structure of water, has not yet been fully clioified. To un rstand the dynamical aspect of water structure and its significant role in life, it is essential to clarify not only the dynamics of water molecules themselves but also the dynamics of water in the aqueous solutions. 

It has been shown in Fig. 4 that the relaxation time x of each electrolyte solution was always longer than that of water in both monovalent and divalent salt aqueous solutions. With increasing salt concentration, not only the relaxation time but also the viscosity 77 of the solutions increases. In Fig. 4 the ratio of viscosity rj/rjwater is shown as a function of concentration. From this figure we can see that the concentration dependence of the ratio x/Xwater has almost the same behavior with that of the ratio n/Hwater- The viscosity is derived from the dynamical property of liquid. From a microscopic point of view, the molecules should be rearranged each other when flow occurs. The relaxation of structure is the process by which molecules of a system "flow" from a non equilibrium configuration to a new... 

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