Guinier law

Sample compositions and scattering length densities are known quantities, hence the adjustable parameters are and a / and if used and 15(0). Uncertainties in a / Rf and may be taken as 2 A, 0.02 and 10 A respectively. We use the multi-model FISH program for our SANS analysis (see reference 13). For dilute non-interacting systems (absence of any obvious S(Q)) estimates for the micelle radii R can also be obtained using the Guinier law which is valid at low Q (QR[Pg.305]

For a homogeneous sphere with radius R, Rg=Rg, oo which may be calculated by the relation R =3I5 R. Thus, a homogenous sphere of 100 nm diameter is characterized by Rg=38.73 nm. The validity of the Guinier-law Equation (17) requires that Rgqlatex systems with sufficient accuracy. 

Guinier law (equation (8-15)), in practice, applies to the scattering intensity produced by a dilute set of polydisperse nano-objects, provided the size distribution has a moderate... 

Guinier law for a two electron density system becomes (Guinier, 1955) h qD)=HPi-pofV c- < -... 

Other methods of analysis based on Guinier law [74,97] invariants [97], and Porod law [93] have also been used. 

---