Fluctuations, structure factor and polytetrahedra in random packings of sticky hard spheres

Dirac peaks appear on the pair correlation function as the packing fraction of the aggregates decreases, indicating the growth of larger and larger regular polytetrahedra, which manifest in two ways on the structure factor, at low and large Q values. These low PF aggregates have a composite structure made of polytetrahedra embedded in a more disordered matrix. Incidentally, the irregularity index of the building tetrahedron appears as a better parameter than the packing fraction to describe various features of the aggregates structure.