Model for r-mers

Let us now consider more closely the thermodynamic properties of the pure y-mer (Prigogine, Trappeniers and Mathot [1953 a, b]). We shall use the following assumptions  

C and D are numerical factors which depend on the geometrical arrangement (cf. 7.1.24). Neglecting non-nearest neighbour interactions we have 

It is also useful to define an average lattice energy per point centre as 

Apart firom the factor q/r this is identical with the expression (7.1.23) v d for a monomer. In defining (16.4.4) we assumed that all the elements of the r-mer are equivalent or, in other words, that the end 

Implicit in this equation is the assumption that the field is completely symmetrical meaning that the slight asynnmetry which is caused by the lack of one or two elements in the shells of first neighbours can be ignored. This assumption could be removed, if necessaiy, by carrying out more detailed calculations. 

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