Figure 5: Structures and calculated absorption spectra of bulk CdSe in ZB and WZ crystal phases.
From: Optical determination of crystal phase in semiconductor nanocrystals
Bonding in (a) ZB and (b) WZ crystal phases, showing staggered (ZB) and eclipsed (WZ) conformations between two adjacent tetrahedral centres. Schematic drawings of (c) ZB and (d) WZ crystals with tetrahedral (Td) and hexagonal (C3v) symmetries, respectively, showing the spatial orientations of the analogous 
and 
lattice directions. (e,f) DFT-simulated absorption spectra and imaginary part of dielectric function (Im(ɛ)) for bulk CdSe with (e) ZB and (f) WZ crystal phases. Im(ɛ) spectra are decomposed into two components indicated in g and h. The BZ is shown for (g) ZB and (h) WZ crystals. Yellow-coloured cylindrical regions in each BZ indicate points along four Λ (Γ to L) directions in ZB and points along Δ (Γ to A) direction in WZ crystals that are structural analogues between the two crystals. Yellow spectra in panels e and f derive from these regions, and blue spectra derive from all other points.
