Neutron Scattering

with the partial structure factor SDD . The symbol for SDD bas the following form
D
D
and describes thé intra- and intermolecular interférences between thé deuterated monomers .
Quite generally, thé scattering cross section can be described as a sum of thépartial structure
factors according to
with the conesponding symbols
dS2 (Q)= V LbDSDD +2b DbHSDH +bHSHH J (14 .19)
s
D D H D H H
D
In case of an incompressible melt thé partial structure factors are related according to
SDD - SHH
-SDH
and thus one gets in correspondence wich Eq .(14 .18)
z
U2 (Q) = Ab
Vs SDD' (14 .21)
The defmition of thé occupation operators in Eq.(14.15) implicitly contains thé condition of
incompressibility, as no free volume is included. The partial structure factor ofthé deuterated
monomers is given
SDD =I)nZ Z P(Q)+q) 2 n 2 ZZ W(Q) (14 .22)
with volume fraction d) of thé polymer component D. Because of thé Babinet principal one
has z P(Q) = - nW and one gets
(14 .20)
14-9