The efficient Wannier polarizability method is used to simulate Raman spectra. In this method, the mean polarizability is expressed as a sum of isotropic polarizabilities attributed to each Wannier function in the system, Ā = β/3 N WF i=1 S 3 i , where S i are the Wannier spreads and the proportionality constant is obtained to be β ≃0.9. Such an expression for the mean polarizability also allows for the decomposition of the total Raman spectra into local contributions and provides a straightforward way for the assignment of Raman peaks (see Supplementary Information).