  We analyze statistical probability distributions of intensities collected by
diffraction techniques like Low-Energy Electron Diffraction. A simple
theoretical model based in hard-sphere potentials and LEED formalism is
investigated for different values of relevant parameters: energy, angle of
incidence, muffin-tin potential radius, maximum spherical component $l_{max}$,
number of stacked layers, and full multiple-scattering or kinematic model.
Given a complex enough system (e.g., including multiple scattering by at least
two Bravais lattices), the computed probability distributions agree rather well
with a $\chi^{2}_{2}$ one, characteristic of the Gaussian Unitary Ensemble
universality class associated to quantum chaos. A hypothesis on the possible
impact of the chaoticity of wavefunctions on correlation factors is tested
against the behaviour of the Pendry R-factor and the Root Mean Squared
Deviation factor.
