Vibrational dynamics and Raman scattering in fractals: A numerical study

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Abstract
The vibrational dynamics and Raman coupling coefficient of site percolating structures have been studied numerically. The main results that emerge from this work are the following (i) Characterization of fractons in k space clarifies the oscillatory nature of the modes and allows an average wavelength to be defined, which is more correlated with frequency than the localization length, which fluctuates strongly; (ii) in these systems, it is not easy to define a local strain due to their essentially disordered structure; (iii) the Raman coupling coefficient scrC(ω) was calculated in the dipole-induced-dipole and bond-polarizability approximations. The scaling laws proposed so far for scrC(ω) do not reproduce the results of our simulation; the difficulty of finding a scaling law in terms of the fractal macroscopic parameters is discussed.