There are a number of methods one could choose to pick structures with low energy and high RMSD. One approach is to select structures above a certain RMSD cutoff (perhaps 1 or 2 Å), and below an energy cutoff (perhaps 2 kcal/mol above the lowest-energy conformer found so far), but this method proved to be unsatisfactory. Notably, such criteria often selected structures with, for example, an RMSD of 2.1 Å, and a relative energy of 1.9 kcal/mol. Here, the RMSD is barely above the threshold, while the energy is barely below it, indicating a conformer unlikely to be useful in searching for better conformers. At the same time, these selection criteria can lead to the exclusion of structures with very high RMSD, but slightly above the energy cutoff. To capture such structures, a better selection rule is needed. The quotient of relative energy divided by RMSD provides a metric that can select for high RMSD and low energy in a less arbitrary fashion. Using this metric, up to 11 conformers with a quotient below 0.5 kcal mol -1 Å-1 were selected, plus the lowest-energy conformer found, for a total of up to 12 new conformers per cycle. Of course, the number of new conformers one wants to generate per cycle can depend on the exact nature of the problem of interest, however, 12 proved suitable for a diversity of dimers and trimers, with and without microhydration (17 distinct complexes in total). To avoid repeatedly exploring the same region of the PES, these conformers are selected subject to the additional constraint that none of the 11 can have an RMSD less than 1 Å relative to each other, to the lowest-energy conformer, or to any conformer selected in a previous cycle. Figure illustrates the difference between these two selection rules, and the conformers which would be selected using each.