Assessment of SAPT and Supermolecular EDA Approaches for the Development of Separable and Polarizable Force Fields.

Which is the best reference quantum chemical approach to decipher the energy components of the total interaction energy: Symmetry-Adapted Perturbation Theory (SAPT) or Supermolecular Energy Decomposition Analysis (EDA) methods? With the rise of physically motivated polarizable force fields (polFF) grounded on these procedures, the need to answer such a question becomes critical. We report a systematic and detailed assessment of three variants of SAPT (namely SAPT2, SAPT2+3, and SAPT(DFT)) and three supermolecular EDA approaches (ALMO, CSOV, and RVS). A set of challenging, strongly bound water complexes, (H2O)2, Zn2+. . .H2O, and F-. . .H2O, is used as "stress tests" for these electronic structure methods. We have developed a procedure to separate the induction energy into the polarization and charge-delocalization using an infinite-order strategy based on SAPT(DFT). This paper aims to provide not only an overview of the capabilities and limitations but also similarities of SAPT and supermolecular EDA approaches for polFF developments. Our results show that SAPT(DFT)/noS2 and ωB97X-D∥ALMO are the most accurate and reliable techniques.