We also determined the parameters of the bonded interactions for the set of fragments using the recently released "Bartender" tool 73 which employs MD simulations at the semiempirical quantum mechanical level of theory as a reference. However, this approach resulted in even higher force constants than those obtained from the previous parametrization using Swarm-CG. This finding is consistent with the work of Pereira et al. , which demonstrated that the molecules described using semiempirical quantum mechanics are usually more rigid than those described by atomistic force fields. In certain cases, the force constants would also need to be manually scaled down, which would probably result in a similar parameter set.