These spectral trends are accurately reproduced in simulations of superlattice extinction using MPM (Fig. ). We model the superlattices by constructing 2D hexagonal lattices containing 11600 nanocrystals, each having one of two Drude dielectric functions using parameters (ω p and γ) determined by fitting the extinction spectra of dilute solvent dispersions of the corresponding nanocrystals (Fig. and Table ). Using MPM, we simulate the normal incidence extinction spectra, averaged over 2 polarizations and 20 superlattices independently prepared by randomly arranging the nanocrystals. The correspondence with the experimental spectra supports our supposition that the lattices are well-mixed, with little to no phase segregation between the two types of ITO nanocrystals, an outcome that would be difficult to directly verify by electron microscopy owing to their very similar electron densities.