Polyethylene was modelled with a RIS model : , , , , and .

Using methods similar to those of section 4, the second and fourth moment of
the end-to-end vector were calculated. For chains of length up to 17monomers these quantities were calculated exactly by generating all
configurations and averaging *R*^{2} respectively *R*^{4}. In Fig. (1.3) is plotted
as a
function of the number of monomers in the chain. Notice that for large *N*the graph approaches a limit value of 5/3:

In Fig. (1.4) the radius of gyration is plotted as a function of

Notice that this behaviour sets in at the same value of