The method of the separated molecular orbitals (SMOs), as a version of the localized representation is discussed as a useful tool for studying weakly interacting systems. As to the Hartree-Fock level, the contributions of the atomic basis sets in some dimers and their counter-poise (CP) corrected systems are compared. The results suggest, that using SMOs the validity of the CP recipe can be demonstrated. The localized many-body perturbation theory (LMBPT) incorporating the method of SMOs makes it possible to study the van der Waals type systems at several levels of correlation. This allows using the SMO-LMBPT scheme for discussing not only the two-body but the many-body interaction energy quantities as well. As an example, the results obtained for the three-body interaction energies in some He-clusters are given. These results show that the three-body effects are negligible in comparison to the two-body ones, the relative significance of the charge-transfer components, on the other hand, are important.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry