Fig. 1

a–c Intermediate scattering function f(q,t) as a function of lag time t measured for bidisperse mixtures of particles of radius 50 nm and 1 μm formulated at a large-to-small volume fraction ratio r of a 0.03, b 0.01, and c 0.003 at wavevectors of q = 6.8 μm⁻¹ (30°, squares), 11.2 μm⁻¹ (50°, diamonds), and 18.7 μm⁻¹ (90°, triangles). Red lines indicate fitting functions: Eq. 2 for r = 0.03 and q = 6.8 μm⁻¹ and Eq. 1 otherwise. d Predicted scattering intensity I(q) for small particles at ϕ = 10⁻³ and large particles at volume fraction ratios of r = 0.03, 0.01, and 0.003 as a function of wavevector q using standard equations for hard spheres.⁵⁰ The range of wavevectors probed by DLS and DDM are indicated by dashed and dash-dotted lines, respectively. e–g Intermediate scattering function f(q,t), extracted from DDM measurements, as a function of lag time t measured for bidisperse mixtures of particles of radius 50 nm and 1 μm formulated at large-to-small volume fraction ratios r of a 0.03, b 0.01, and c 0.003. For each ratio, data were analyzed over the wavevector range 0.98 μm⁻¹ < q < 3.01 μm⁻¹; the figure shows representative correlation functions obtained for wavevectors q = 1.08 μm⁻¹ (squares), 2.05 μm⁻¹ (diamonds), or 2.92 μm⁻¹ (triangles). Red lines indicate fits to Eq. 4