Scattering intensity limit value at very small angles

Abstract

The existence of a limit of the sample scattering intensity, as the scattering vector approaches zero, requires and is ensured by the property that the mean value of the scattering density fluctuation over a volume V behaves asymptotically, at large V, as νV −1/2, ν being an appropriate constant. The limit of the normalized scattering intensity is then equal to ν2. The implications of this result are also analysed in the case of samples made up of two homogeneous phases.