Abstract: Method, systems, and devices for designing a test molecule are disclosed. An example method includes using a molecular simulator to generate sets of simulation data. Each set of simulation data may include simulation data indicative of simulated locations in a solvent of (i) molecules of a reference molecule and (ii) molecules of one of M test molecules. The method may also include determining a probability of contact between an a species and a ? species for each set of simulated data. A contact may occur when a particle of the ? species is within a range of radials distances from a particle of the ? species. Each of the a species and the ? species may be one of the reference molecule, the solvent, or one of the M test molecules. The method may further include determining a simulation result based on at least one probability of contact.