Depending on the type of exploration, either flexible or rigid monomers are used. In the former case, only one conformer for each species needs to be supplied. In the latter case, including the lowest energy conformer of each monomer is a good starting point but adding other conformers and/or assorted protonation states improves the exploration. Figure depicts such a combination of rigid monomers to construct the (H 2 SO 4 ) 3 (NH 3 ) 3 cluster.