Water Pauling model

An important advance in the understanding of the chemical behaviour of glasses in aqueous solution was made in 1977, when Paul (1977) published a theoretical model for the various processes based on the calculation of the standard free energy (AG ) and equilibrium constants for the reactions of the components with water. This model successfully predicted many of the empirically derived phenomena described above, such as the increased durability resulting from the addition of small amounts of CaO to the glass, and forms the basis for our current understanding of the kinetic and thermodynamic behaviour of glass in aqueous media. 

Kanivetsky, R. (2000) Arsenic in Minnesota Ground Water Hydrochemical Modeling of the Quaternary Buried Artesian Aquifer and Cretaceous Aquifer Systems, Report of Investigations — Minnesota Geological Survey, St. Paul, MN. 

There are important differences between the literature models and our results. In our case, (i) the number of monomers is smaller than that in the Pauling model (where they are present in clathrate-like cages), and (ii) they coexist with a disturbed but still infinite, not disintegrated network of water molecules. In contrast, the models in refs 11 and 32 do not involve a network but only a distribution of clusters. 

Therefore, we can assign Nq= holes per lattice molecule.) This value was used by Mikhailov (1967) for the Samoilov model. In the Pauling model, the assignment of Nq depends on whether we count all the holes in the lattice as suitable for accommodating water molecules, or only the larger cavities. The choice of Frank and Quist (1961) was ATq = J. 

The system consists of Nw water molecules at a specified temperature T and pressure P. A total of Nl molecules participate in the formation of a regular lattice with a well-defined structure, which for our purposes need not be specified. (It may be an ice L structure, as in the Samoilov model, or a clathrate type of structure, as in the Pauling model.) The lattice is presumed to contain empty spaces, or holes. We let Nq be the... 

Later, Paul and Paddison presented a statistical mechanical model that was used to calculate the dielectric permittivity in the water domains, that is, the pores, of Nafion.234 For computational purposes, a pore was taken as being of cylindrical geometry. The main prediction is that in a fully hydrated... 

Bradbury, M. H. Baeyens, B. 2002. Pore-water Chemistry in Compacted Resaturated MX-Bentonite Physicochemical Characterisation and Geochemical Modelling. Paul Scherrer Institut, Villigen, Switzerland, PSI Berichl Nr. 02-10, 42... 

Clathrate-Cage Model. The final water model which is of major interest is based on clathrate hydrate cage structures. It was originally proposed by Pauling (116), who noted the existence of clathrate hydrates of many inert gases and suggested, by analogy to the chlorine hydrate,... 

Because of the analogy between (H20)n and (02Si)n, the problems associated with the structural interpretation of liquid water have their glassy state analogies in the theories of glass structure. Even Pauling s clathrate hydrate model for liquid water has its counterpart in the vitron theory of glass [750]. Both theories are discredited by the experts in the Held. 

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