Molecular-orbital study of Li and LiOH adsorption on a Cu(001) surface. II. Cluster-model calculations with image charges

Hartree-Fock and configuration-interaction calculations were performed for (Formula presented) Li and (Formula presented) LiOH, as models of Li/Cu(001) and LiOH/Cu(001), respectively. To take into account the dielectric-response effect of the metal surface to external point charges, we used cluster models with image charges. For (Formula presented) Li, the calculated vibrational frequency was almost the same as that given by a cluster model without image charges, and both values agreed well with the experimental value. Image charges improved the Li-OH vibrational frequency for (Formula presented) LiOH. On the other hand, simple cluster calculations without image charges gave poor results for work-function changes upon Li and LiOH adsorption; however, by considering image charges, we obtained excellent results, were comparable to the observed values.