Basis Set Superposition Error on Structures and Complexation Energies of Organo-Alkali Metal Iodides

摘要

Theoretical studies have been performed to study the binding characteristics of the alkali metal iodides, M-I (M= Li, Na, K), to poly(ethylene oxide) (PEO, I), poly(ethylene amine) (PEA, IT) and poly(ethylene N-methylamine) (PEMA, III) via the B3LYP method. In this study, two types of complexes, singly-coordinated systems (SCS) and doubly-coordinated systems (DCS), were considered, and dissociation energies (AEd) were calculated both with and without basis set superposition error (BSSE). Two types of counterpoise (CP) approach were investigated in this work, but the AEd values corrected by using the function CP (fCP) correction exhibited an unusual trend in some cases due to deformation of the sub-units. This problem was solved by including geometry relaxation in the CP-corrected (GCP) interaction energy. On the other hand, the effects of the BSSE on the structures were very small when the complexes were re-optimized on the CP-corrected (RCP) potential energy surface (PES), even if the bond lengths between X and M~+ (d_(X-M~+)) and between M~+ and I (d_(M~+-I~-)) were slightly lengthened. Therefore, neither the GCP nor RCP corrections made much difference to the dissociation energies.