Guinier plot

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Guinier analysis attempts to extract the size-scale for a structure by fitting the scattering to an equation of the form

or equivalently,

Thus a straight line in a plot of ln(I) vs. q2 is indicative of Guinier scaling and suggests that a system is essentially monodisperse, and can therefore be used as a means of quality control before further data analysis (e.g. Form factor). Such an analysis is typically only done with the low-q portion of the data.

Smaller particles require measurement of lower q for Guinier analysis, as Guinier scaling is only maintained up to a certain maximum q:

  • For spherical particles,
  • For elongated particles,

See Also