The Form Factor
The form factor is a function that describes how (d / d
)(Q) is modulated by interference effects between radiation scattered by different parts of the same scattering body. Consequently it is very dependent on the shape of the scattering body. The general form of P(Q) is given by Van de Hulst’s equation2
... (10)
where is a "shape parameter" that might represent a length or a radius of gyration, for example. Fortunately analytic expressions exist for most common shapes and expressions for more complex topologies (for example, concentric cylinders34 or hinged rods35) can usually be deduced from these. A selection of form factors are shown in Table 4.