Electrical interaction

Either the same or different approximations may be used to treat the binding at r = L and the remaining electrical interactions between the ions. The excess energy of the sticky electrolyte is given by... 

Figure A2.3.18 The excess energy in units of NkT as a fiinction of the concentration for the RPM and SEM 2-2 electrolyte. The curves and points are results of the EfNC/MS and HNC approximations, respectively, for the binding and the electrical interactions. The ion parameters are a = 4.2 A, and E = 73.4. The sticking coefficients = 1.6x10 and 2.44x 10 for L = all and a/3, respectively.

Studies of electrical interactions in proteins, polypeptides, and amino acids started over 60 years ago [1]. To a large extent, electrostatic properties of proteins are determined by the ability of certain amino acids to exchange protons with their environment and the dependence of these processes on pH. The proton occupies a special position as a promoter and iiuxliator in... 

Edsall, J. T. George Scatchard, John G. Kirkwood, and the electrical interactions of amino acids and proteins. Trends Biochem. Sci. 7 (1982) 414-416. Eigen, M. Proton transfer, acid-base catalysis, and enzymatic hydrolysis. Angew. Chem. Int. Ed. Engl. 3 (1964) 1-19. 

This is one approach to the explanation of retention by polar interactions, but the subject, at this time, remains controversial. Doubtless, complexation can take place, and probably does so in cases like olefin retention on silver nitrate doped stationary phases in GC. However, if dispersive interactions (electrical interactions between randomly generated dipoles) can cause solute retention without the need to invoke the... 

The majority of particles adhere to surfaces, as well as to each other, through electrical interactions. These can be either electrostatic, due to the presence of a static charge on the particle, or electrodynamic, as might be the case for London or van der Waals forces. Indeed the relative roles of both of the.se types of interactions has been the subject of much debate for many years [70-78]. 

Polarizability (Section 5.4) The measure of the change in a molecule s electron distribution in response to changing electric interactions with solvents or ionic reagents. 

A measurement of the density of helium gas shows that it is a monatomic gas. Molecules of He2 do not form. What difference between hydrogen atoms and helium atoms accounts for the absence of bonding for helium The answer to this question also must lie in the attractive and repulsive electrical interactions between two helium atoms when they approach each other. Figure 16-4A shows the attractive forces in one of our hypothetical instantaneous snapshots. There are, of course, four electrons and each is attracted to each nucleus. In Figure 16-4B we see the repulsive forces. Taking score, we find in Figure 16-4A eight attractive interactions, four... 

In effect the chemist, and chemistry teacher, explains the observed chemical behaviour of matter (substances) - colour changes, precipitation from solution, characteristic flame colours, etc. - in terms of the very differenthQ miom of the quanticles that are considered to form the materials at the sub-microscopic level. Much of this involves the reconfiguration of systems of negative electrons and positively charged atomic cores (or kernels ) due to electrical interactions constrained by the allowed quantum states. 

For Problems 8.59-8.62, explain your rankings in terms of quantum numbers and electrical interactions. 

Figure 20-12 summarizes the electrical interactions of an octahedral complex ion. The three orbitals that are more stable are called 2 g orbitals, and the two less stable orbitals are called Sg orbitals. The difference in energy between the two sets is known as the crystal field splitting energy, symbolized by the Greek letter h. 

Extensive forces arise from the electrical interaction between coimterions and polyions. There are two repulsive forces which act to extend a polyion. One results from coulombic repulsion between the charged groups on the polyion and the other from osmotic pressure of the counterions within, which seek to increase the space in which they can move. 

Because of the electric interaction, hydrogen-bonded molecules hold on to each other more tightly than those in substances with pure covalent bonds. This cohesiveness is why water is a liquid at room temperature, whereas heavier covalent-bonded molecules such as chlorine, in the form of CI2, are gases. 

The theory of Debye and Hiickel started from the assumption that strong electrolytes are completely dissociated into ions, which results, however, in electrical interactions between the ions in such a manner that a given ion is surrounded by a spherically symmetrical distribution of other ions mainly of opposite charges, the ionic atmosphere. The nearer to the central ions the higher will be the potential U and the charge density the limit of approach to the central ion is its radius r = a. 

Two of the three SI base units have in the meantime acquired redefinitions in atomic terms (e.g., the second is now defined as 9 192 631 770 hyperfine oscillations of a cesium atom). However, the definitions (C.2a)-(C.2c) conceal another unfortunate aspect of SI units that cannot be overcome merely by atomic redefinitions. In the theory of classical or quantal electrical interactions, the most fundamental equation is Coulomb s law, which expresses the potential energy V of two charged particles of charge q and 2 at separation R as... 

There are also problems arising from the electrical interactions between different pigments and between pigments and the media in which they are dispersed, particularly when these are liquid paints and inks. This topic is discussed in the textbooks by Parfitt and Apps (amongst others), given in the bibliography at the end of this chapter. 

Electric interactions are screened by electrolytes. Hence, by adding electrolytes, the adsorption behavior is made to resemble that of uncharged macromolecules (see Fig. 4.17). 

Coarse particles have a much lower specific surface, and consequently surface forces and electrical interactions between particles are of very much less significance than in the fine particle systems considered in the previous sections. Flocculation will be absent and, generally, the particles will not influence the rheology of the liquid. The dividing point between coarse and fine particles is somewhat arbitrary although is of the order of 0.1 mm (100 pm). 

Energy transfer probabilities due to multipolar magnetic interactions also behave in a similar way to that previously discussed for multipolar electric interactions. Thus, the transfer probability for a magnetic dipole-dipole interaction also varies with 1 / 7 , and higher order magnetic interactions are only influential at short distances. In any case, the multipolar magnetic interactions are always much less important than the electric ones. 

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