Figure 2.
Sensitivity of the diffuse scattering function to short-range compositional order and its effects. (a) Calculated diffuse scattering patterns for KCl0.5Br0.5 considering only compositional order, as characterised by the Warren–Cowley parameter α (see text). Only one quadrant of the hk0 section is shown, such that the centre of reciprocal space lies at the bottom-left corner of each image. (b) Corresponding diffuse scattering patterns calculated after allowing relaxation of atomic positions according to the empirical potential reported in Catlow et al. (1977) ▸. (c) The corresponding thermal diffuse scattering patterns calculated using the SCLD approach described in the main text. (d) The total diffuse scattering function, obtained as the sum of static [panel (b)] and dynamic [panel (c)] contributions. We consider the match to experiment [Fig. 1 ▸(c)] to be closest for the α = 0.6, 0.8 values.