Absence of Definite Scaling Laws in Raman Scattering from Fractals

The frequency dependence of the Raman coupling coefficient C ( ω ) is calculated numerically for square and cubic percolation clusters. No general scaling law in terms of the macroscopic parameters such as the fractal ( D ) and fracton ( d ) dimensions is found. C ( ω ) is sensitive to the microscopic structure of the clusters and depends on: site- or bond- percolation, presence or absence of dangling bonds, scattering mechanism and polarization, presence or absence of polarizability disorder. This situation makes the derivation of macroscopic parameters from Raman experiments unreliable.