Ion loose

These ions loose energy internally to phonons (lattice vibrations), a process called decay or relaxation, to reach the 4In/2 and 4Ii3/2 energy levels ... 

The bare negative ions discussed in Problem 2.23 have a greatly enhanced reactivity. The small amounts of salts that dissolve in nonpolar or weakly polar solvents exist mainly as ion-pairs or ion-clusters, where the oppositely charged ions are close to each other and move about as units. Tight ion-pairs have no solvent molecules between the ions loose ion-pairs are separated by a small number of solvent molecules. 

In polar solvents, polar exciplexes (contact ion pairs) dissociate into non-fluorescent radical ions (loose ion pairs or free ions) due to the stabilization of the separated ions by solvation. It has been observed that exciplex emission decreases with increasing polarity of the solvent and that at the same... 

The same approach, using the simple solvation model, could be used to compare the deposition of one specific metal ion on various metal substrates. However, a more important problem is the realistic description of the whole process of metal deposition, including the desolvation of the metal ion as it reproaches the surface. In principle, the latter aspect can be treated by molecular dynamics, and first results have already been obtained a few years ago [81]. What is missing is the incorporation of such simulations into a fiumewoik that contains all of the electronic interactions. In this way, we should be able to understand what has been termed the enigma of metal deposition [78] Why is the deposition of certain metal ions so fast The deposition of silver, for example, is one of the fastest electrochemical reactions known, even though the ion looses about 6 eV of solvation energy during the process. So we close this chapter on an optimistic note we believe we now have the tools at hand to answer such fundamental questions. 

FIGURE 3.13 Schematic representation of the Gouy-Chapman-Stern-Grahame theory. Compare with Figure 3.11 Two planes of closest approach are defined, the outer Helmholtz plane, where ions that retain their hydration layer are adsorbed (nonspecific adsorption) and the inner Helmholtz plane, is defined as the distance where ions loosing the hydration layer (specifically adsorbed) to the surface. 

Figure 7.8 Structure of P-alumina. The spinel blocks with cubic close-packed oxygen ordering are separated by open layers of oxygen ions loosely bound to monovalent...

For larger ions such as Cs+ ions, loose hydrophobic hydration shells are formed around these ions. However, water molecules try to keep their integrity as pure water clusters. Because the direct cation-anion interaction, which will lead to fewer water molecules participating in the hydration shells, is energetically more favorable, the primary coordination number increases faster as a function of salt concentration. For the intermediate ion combination (e.g., Rb+ and Cl"), the ion-water and the ion-ion interactions are in close competition. 

Second method. NMR measurements of water proton chemical shifts upon addition of Co to TMA-PP solutions have been recently reported [23]. In these experiments it was observed that up to a value of about 0.5 for the ratio r= [Co ]/[TMA-PP], all of the Co " " ions introduced into the polyelectrolyte solution lose all of their hydration water. On the contrary, at r >0.5, the added cobalt ions loose only little of their hydration water. To solve Equations (14) and (15) within the framework of the kinetic model represented by Equation (5) we have assumed that the cobalt ions bound with complete dehydration correspond to those in state PC3 in Equation (5). Therefore, using Equation (10), one can write ... 

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