Fig. 1

Normalized diffusion coefficient D/D ₀ for A-type particles, computed with Eqs. (23) and (25), plotted vs. the intermolecular average distance d of B-type particles (expressed in adimensional units l). The B-particles interact through a Coulombic potential \(U=\bar {\mathcal {C}}_{Coul}l^{-1}\). The A- and B-type particles are assumed spherical, of equal radius R, and equal mass m. In adimensional units the interaction intensity is \(\bar {\mathcal {C}}_{Coul}=U_{Coul}(R)/(k_{B}T)\), the friction coefficient γ=Γ(k _B T m)^1/2 R ⁻¹. The curves refer to a fixed value for the potential strength (\(\bar {\mathcal {C}}_{Coul}=70\)) and different values for Γ, that is: Γ=0.1 (blue continuous line), Γ=0.05 (orange dot-dashed line), Γ=0.01 (green dashed line), Γ=0.005 (red dotted line). The case of \(\bar {\mathcal {C}}_{Coul}=0\) has been reported for Γ=0.01 (black dot dashed line)