Someone can provide me a reference for determining from a computer simulation of a colloidal system if this flocculating or has precipitated ? I recommend criteria to determine this?
If your particles are of reasonable size, you might be interested in calculating the free energy profile for the association of two such molecules (e.g., using umbrella sampling). Then you can compute the standard free energy of dimerization, and then estimate the population of free particles there are in the relevant range of concentrations. The less features your particle has, the easier this should be.
Of course, this neglects many-body effects, but important features -- such as the overall thermodynamics of association, kinetic barriers or potential wells responsible for flocculation -- will already be there.