ABINITIO CALCULATIONS OF THE INTERACTION OF IONS WITH NEUTRAL LIGANDS - PAIR POTENTIALS FOR LI+-ETHER-SYSTEMS, LI+-THIOETHER-SYSTEMS, AND LI+-AMIDE-SYSTEMS

The interaction of Li+ with model compounds (ethers, amides, and a thioether) of interest as building blocks in ionophores is studied by performing ab initio SCF-LCAO-MO calculations in sufficient numbers so as to be able to scan the potential energy hypersurface for the lithium ion in the field of the model compound. As previously reported for the case of Na+, atom pair potentials are obtained by fitting the SCF-LCAO-MO energies with an analytical potential of simple form. The pair potentials were found transferable, i.e., the energy minimum for the interaction of Li+ with molecules different from those used for the model calculations is properly described by using these analytical potentials. The analysis of the inter- and intramolecular atom-pair interactions indicates that the Li+/ligand binding is primarily due to the polarization of the model compound in the field of the lithium ion. The position of the minima and the corresponding interaction energies are compared with those reported by F. Hinton et al., by A. Pullman et al., and with the experimental results. © 1980 American Institute of Physics.