Egan and Paesani analyzed many-body effects in these systems using high-level coupledcluster calculations. They found that in OH -(H 2 O) 5 , three-body effects amount to up to 60 kJ/mol, four-body effects to up to 8 kJ/mol, and five-body effects still contribute up to 2 kJ/mol. The lowest-energy clusters of each size were also used as test case in Ref. .