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 R2 respectively R4. In Fig. (1.3) is plotted
as a
function of the number of monomers in the chain. Notice that for large Nthe graph approaches a limit value of 5/3: