An Assessment of SAPT and Supermolecular EDAs Approaches for the Development of Separable and Polarizable force fields

What is the best quantum chemical approach to decipher the energy components of the total interaction energy: Symmetry-Adapted Perturbation Theory or Supermolecular Energy Decomposition Analysis? This is a very common question that force fields (FF) developers ask themselves when designing new classical intermolecular potentials. With the rise of physically motivated polarizable FFs able to include various type of physical effects within simulations, the need to answer such an interrogation becomes this http URL this paper, we perform a systematic & detailed assessment of three variants of SAPT:SAPT(2), SAPT(2+3) & SAPT(DFT) & three supermolecular EDAs approaches : ALMO, CSOV & RVS on a set of challenging, strongly bouded water complexes with cations and anions.Using a regularization scheme within SAPT(DFT), RegSAPT(DFT), to partition the second-order induction energy into its polarization and charge delocalization contributions, we show how the single-exchange (S2) approximation has a large effect on these energies, and provide additional evidence for not using the initial Stone--Misquitta definition for charge delocalization.Alternatively,we obtain more satisfactory results for the evaluation of the polarization & charge-delocalization energies using an infinite order this http URL we compute these quantities using SAPT(DFT), RegSAPT(DFT) & classical polarization models, we show a convergence with EDAs, despite the observation of sizable residual differences. Overall, for strongly polar systems, when separable physically motivated energies are needed, we recommend the use of SAPT(DFT) without the S2 approximation, the supermolecular EDA ALMO WB97X-D being our second choice. As neither SAPT(2) nor SAPT(2+3) can be fully freed from the S2 approximation,we do not recommend either of these methods for a separable, physically motivated decomposition of the interaction energy.