J. Phys. IV France
Volume 03, Numéro C8, Décembre 1993
IX International Conference on Small Angle Scattering
Page(s) C8-511 - C8-514
IX International Conference on Small Angle Scattering

J. Phys. IV France 03 (1993) C8-511-C8-514

DOI: 10.1051/jp4:19938106

Oscillating and non-oscillating contributions in the Porod law


Laboratory of Experimental Physics, Institute of Physics B5, University of Liège, 4000 Liège, Gelgium

Experimental Ih4 plots often show damped oscillating terms. The first non-oscillating term describing the interface curvature effects is given by the Kirste-Porod formula for regular surfaces. It provides a positive h-2 contribution to Ih4. In the presence of sharp edges and vertices on otherwise planar interfaces an additional negative h-2 term occurs. A cylinder cutted following a planar section parallel to its axis provides the simplest situation where oscillating, positive and negative h-2 terms have to be simultaneously taken into account. The three additional asymptotic contributions to Ih4 are evaluated. The exact correlation function is calculated. The difference between its fourier transform and the asymptotic intensity yields an estimate of the neglected contribution using the asymptotic expansion. The modification of the oscillating Ih4 pattern resulting from the positive and negative h-2 contributions is examined.

© EDP Sciences 1993