Onsager bodies”

The Debye-Huckel-Onsager equation has been tested against a large body of accurate experimental data. A comparison of theory and experiment is shown in Fig. 4.93 and Table 4.21 for aqueous solutions of true eiectroiytes, i.e., substances that consisted of ions in their crystal lattices before they were dissolved in water. At very low concentrations (< 0.(X)3 N), the agreement between theory and experiment is very good. There is no doubt that the theoretical equation is a satisfactory expression for the limiting tangent to the experimentaiiy obtained/ versus curves. 

In summary, Onsager s extension of the Debye-Hiickel theory to the nonequilibrium properties of electrolyte solutions provides a valuable tool for deriving single ion properties in electrolyte solutions. Examination of the large body of experimental data for aqueous electrolyte solutions helped confirm the model for a strong electrolyte. In more recent years, these studies have been extended to non-aqueous solutions. Results in these systems are discussed in the following section. 

Since then, a large body of work, both theoretical and experimental, has dealt with the Onsager model and the N/I phase transition of hard rods. This subject has been recently reviewed by Vroege and Lekkerkerker [43], A major improvement was brought by Khokhlov and Semenov who considered the effects of rod flexibility [44],... 

Solvent interactions in the present study have been calculated by following the approach of Sinanoglu [2] who separates mathematically the solvation energies into two parts or steps. In the first step a hole is prepared in the liquid. In the second step a solute molecule is placed in the hole and interacts with its new environment. In calculating the interaction energy of the solute molecule with its environment the concept of continuum reaction field of Onsager [24] has been applied. The solvent is considered as a continuum which possesses the macroscopic dielectric properties of the solution, which coincide with those of a pure liquid in the case of a dilute solution. A fuller description of the theory and computational details will be presented in Section 2.2 and in Section 3. Our procedure differs from that presented by Sinanoglu [2] in the calculation of dispersion interaction, which follows the method developed by Linder [25], which takes into account many body effects and thermodynamic fluctuations. The calculational scheme has been already applied by Nir [26] for the... 

Unlike other branches of physics, thermodynamics in its standard postulation approach [272] does not provide direct numerical predictions. For example, it does not evaluate the specific heat or compressibility of a system, instead, it predicts that apparently unrelated quantities are equal, such as (1 A"XdQ/dP)T = - (dV/dT)P or that two coupled irreversible processes satisfy the Onsager reciprocity theorem (L 2 L2O under a linear optimization [153]. Recent development in both the many-body and field theories towards the interpretation of phase transitions and the general theory of symmetry can provide another plausible attitude applicable to a new conceptual basis of thermodynamics, in the middle of Seventies Cullen suggested that thermodynamics is the study of those properties of macroscopic matter that follows from the symmetry properties of physical laws, mediated through the statistics of large systems [273], It is an expedient happenstance that a conventional simple systems , often exemplified in elementary thermodynamics, have one prototype of each of the three characteristic classes of thermodynamic coordinates, i.e., (i) coordinates conserved by the continuous space-time symmetries (internal energy, U), (ii) coordinates conserved by other symmetry principles (mole number, N) and (iii) non-conserved (so called broken ) symmetry coordinates (volume, V). 

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