  We formalize within the percolation scheme, that operates along the linear
chain approximation, namely at one dimension (1D), an intrinsic ability behind
Raman scattering to achieve a quantitative insight into local clustering or
anticlustering in an alloy, using SiGe as a case study. For doing so, we derive
general expressions of the individual fractions of the six SiGe
percolation-type oscillators [1(Ge-Ge), 3(Si-Ge), 2(Si-Si)], which monitor
directly the Raman intensities, via a relevant order parameter k. This is
introduced by adapting to the 1D oscillators of the SiGe diamond version of the
1D percolation scheme, namely along a fully consistent 1D treatment, the
approach originally used by Verleur and Barker for the three-dimensional (3D)
oscillators of their 1D cluster scheme applying to zincblende alloys [H.W.
Verleur and A.S. Barker, Phys. Rev. 149, 715 (1966)], a somehow problematic one
in fact, due to its 3D vs. 1D ambivalence. Predictive k-dependent intensity
interplays between the SiGe (50 at.%Si) Raman lines are confronted with
existing experimental data and with ab initio Raman spectra obtained by using
large (32 atom) disordered supercells matching the required k values, with
special attention to the Si-Ge triplet and to the Si-Si doublet, respectively.
