In the Section IV, we can find the "Raman scattering in disordered carbon". First, the "Raman modes in single crystals obey the fundamental selection rule q≈0, where q is the wave vector of the scattered phonon". However, on phonons we have sample boundary effects and grain boundaries, that is, finite-size domains, and therefore "the selection rule is relaxed to allow the participation of phonons near Γ, with Δq ~ 2π/d, where d is the dimension of the crystalline domain". According to Nemanich, Solin, and Martin, 1981, "the Raman scattering intensity of a finite crystal is given by" (Eq.6 in Ferrari and Robertson):