Such force-integration approach was also used for calculating the partial three-particle PMF 𝑊 % A (𝑑 4! , 𝑑 4% , 𝑑 !% ) on a 2D grid {𝑑 4% , 𝑑 !% } representing location of NP3 for each fixed distance 𝑑 4! between NP1 and NP2 (see Fig. ). We moved NP3 along the vertical gridlines representing reaction coordinates, defining 𝜉 as the vertical distance of NP3 from the horizonal axis passing through the NP1-NP2 dimer. To traverse each reaction coordinate, we placed NP3 at a distance 𝜉 ' = 11𝜎 and moved it in a stepwise manner towards the fixed dimer along the coordinate, first at steps of Δ𝜉 = 0.15𝜎 until a distance of 𝜉 = 2𝜎 was reached, then at steps of Δ𝜉 = 0.05𝜎 until 𝜉 = 1𝜎, then at steps of Δ𝜉 = 0.02𝜎 until 𝜉 = 0.2𝜎, and finally at steps of Δ𝜉 = 0.01𝜎 until contact.