An Incomplete-Dissociation Model for Diffusion and Ionic Conduction in Pure Molten Salts

1983 ◽  
Vol 38 (5) ◽  
pp. 516-519 ◽  
Author(s):  
A. Klemm

Diffusion and ionic conduction in pure 1:1 molten salts is described by an incomplete-disso­ciation model comprising neutral diatomic molecules and monoatomic ions. The internal mobility b+- and the self-diffusion coefficients D+ and D- are given in terms of the six inter­particle friction coefficients and the degree of dissociation. By an approximation it is possible to derive from experimental D+ and D- values an apparent degree of dissociation which ranges from 0.93 for NaCl to 0.51 for TlCl and decreases with temperature.

2021 ◽  
Vol 11 (11) ◽  
pp. 5070
Author(s):  
Xesús Prieto-Blanco ◽  
Carlos Montero-Orille

In the last few years, some advances have been made in the theoretical modelling of ion exchange processes in glass. On the one hand, the equations that describe the evolution of the cation concentration were rewritten in a more rigorous manner. This was made into two theoretical frameworks. In the first one, the self-diffusion coefficients were assumed to be constant, whereas, in the second one, a more realistic cation behaviour was considered by taking into account the so-called mixed ion effect. Along with these equations, the boundary conditions for the usual ion exchange processes from molten salts, silver and copper films and metallic cathodes were accordingly established. On the other hand, the modelling of some ion exchange processes that have attracted a great deal of attention in recent years, including glass poling, electro-diffusion of multivalent metals and the formation/dissolution of silver nanoparticles, has been addressed. In such processes, the usual approximations that are made in ion exchange modelling are not always valid. An overview of the progress made and the remaining challenges in the modelling of these unique processes is provided at the end of this review.


Author(s):  
Victor P. Arkhipov ◽  
Natalia A. Kuzina ◽  
Andrei Filippov

AbstractAggregation numbers were calculated based on measurements of the self-diffusion coefficients, the effective hydrodynamic radii of micelles and aggregates of oxyethylated alkylphenols in aqueous solutions. On the assumption that the radii of spherical micelles are equal to the lengths of fully extended neonol molecules, the limiting values of aggregation numbers corresponding to spherically shaped neonol micelles were calculated. The concentration and temperature ranges under which spherical micelles of neonols are formed were determined.


1974 ◽  
Vol 14 (6) ◽  
pp. 915-918
Author(s):  
A. M. Sazonov ◽  
V. M. Olevskii ◽  
A. B. Porai-Koshits ◽  
V. N. Skobolev ◽  
G. A. Shmuilovich

2012 ◽  
Vol 1 (6) ◽  
pp. 334-346 ◽  
Author(s):  
Rafik Besbes ◽  
Noureddine Ouerfelli ◽  
Manef Abderabba ◽  
Patric Lindqvist-Reis ◽  
Habib Latrous

1986 ◽  
Vol 41 (7) ◽  
pp. 939-943 ◽  
Author(s):  
E. Hawlicka

The self-diffusion coefficients of Na+, Cl- and I- in methanol-water solutions at 35 ± 0.01 °C have been measured in their dependence on the salt molarity in the range 1 · 10-4- 1 · 10-2 mol dm -3. The ionic self-diffusion coefficients in infinitely diluted solutions have been computed. The influence of the solvent composition on the solvation of the ions is discussed. A preferential hydration of Na+, Cl- and I- ions in water-methanol mixtures has been found.


1994 ◽  
Vol 49 (3-4) ◽  
pp. 258-264 ◽  
Author(s):  
D. Girlich ◽  
H.-D. Lüdemann ◽  
C. Buttersack ◽  
K. Buchholz

The self diffusion coefficients D of the water molecules and of sucrose have been determined by the pulsed field gradient NMR technique over a wide range of temperatures and concentrations (cmax: 70% w/w suc.). All temperature dependencies can be fitted to a Vogel- Tammann-Fulcher equation. The isothermic concentration dependence of D for the sucrose is given by a simple exponential concentration dependence


1992 ◽  
Vol 47 (10) ◽  
pp. 1047-1050 ◽  
Author(s):  
C. Herdlicka ◽  
J. Richter ◽  
M. D. Zeidler

AbstractSelf-diffusion coefficients of 7Li+ ions have been measured in molten LiNO3 with several compositions of 6Li+ and 7Li+ over a temperature range from 537 to 615 K. The NMR spin-echo method with pulsed field gradients was applied. It was found that the self-diffusion coefficient depends on the isotopic composition and shows a maximum at equimolar ratio. At temperatures above 600 K this behaviour disappears.


2008 ◽  
Vol 139 ◽  
pp. 101-106 ◽  
Author(s):  
Byoung Min Lee ◽  
Shinji Munetoh ◽  
Teruaki Motooka ◽  
Yeo Wan Yun ◽  
Kyu Mann Lee

The structural properties of SiO2 liquid during cooling have been investigated by molecular dynamics simulations. The interatomic forces acting on the particles are calculated by the modified Tersoff potential parameters. The glass transition temperature and structural properties of the resulting SiO2 system at various temperatures have been investigated. The fivefold coordinations of Si and threefold coordinations of O atoms were observed, and the coordination defects of system decrease with decreasing temperature up to 17 % at 300 K. The self-diffusion coefficients for Si and O atoms drop to almost zero below 3000 K. The structures were distorted at high temperatures, but very stable atomic network persisted up to high temperature in the liquid state.


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