Temperature Dependent Interaction Non-Additivity in the Inorganic Ionic Clusters

Interaction non-additivity in the chemical context means that binding of certain atom to a reference atom cannot be fully predicted from the interactions of these two atoms with other atoms. This constitutes one of key phenomena determining an identity of our world, which would have been much poorer otherwise. Ionic systems provide a good example of the interaction non-additivity in most cases due to electron transfer and delocalization effects. We report Born-Oppenheimer molecular dynamics (BOMD) simulations of LiCl, NaCl, and KCl at 300, 1500, and 2000 K. We show that our observations originate from interplay of thermal motion during BOMD and cation nature. In the case of alkali cations, ionic nature plays a more significant role than temperature. Our results bring fundamental understanding of electronic effects in the condensed phase of ionic systems and foster progress in physical chemistry and engineering.