Importance of nonadditive collective effects on chemisorption and catalysis: Part I. Interactions of lithium atom clusters with hydrogen

Abstract In this paper a theoretical method to evaluate the collective effects involved in adsorbate-metal surface interactions is discussed. The main feature of the method is the breakdown of the total interaction energy into its many-body contributions, allowing identification of the degree of delocalization of the adsorbate interaction into the atomic components of the active metal center. Moreover, the many-body analysis is related to the catalytic effect, presenting the catalyst as a third body promoting the breaking of chemical bonds in the dissociative adsorption process. The usefulness of the method to predict the character (local or collective) of the interactions is presented through its application to the sytems Li n -H (where n = 1, 2, 3,…, 10) and Li-H 2 .