J. Phys. I France
Volume 6, Numéro 10, October 1996
Page(s) 1365 - 1376
DOI: 10.1051/jp1:1996141
J. Phys. I France 6 (1996) 1365-1376

Structure Factors for Fractal Aggregates Built Off-Lattice with Tunable Fractal Dimension

Romain Thouy and Rémi Jullien

Laboratoire des Verres, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier, France

(Received 26 March 1996, revised 23 May 1996, accepted 20 June 1996)

Structure factors for fractal aggregates with a range of fractal dimensions have been studied. To this end, a hierarchical computer algorithm is presented which is able to build, in the three-dimensional space, disordered off-lattice fractal aggregates made of identical tangent spheres, whose fractal dimension can be varied from 1 up to an upper limit of about 2.55. The correlation functions and their Fourier transforms S(q) (structure factors) are calculated for various fractal dimensions. It is shown that the S(q) curve exhibits a characteristic sigmoidal shape for D>2 and that it is necessary to include a cluster size power-law polydispersity to recover a power-law behavior of S(q) in a large range of q values, as observed in experiments.

© Les Editions de Physique 1996