Studies of the local reactivity of surfaces using chemical based principles

We apply the local version of the hard and soft acids and bases (HSAB) principle to infer the chemical reactivity of surface-like systems. Based on properties of the isolated reactants, the HSAB principle allows us to predict the most reactive sites of a polyatomic system. For the sake of simplicity the surface was simulated by a planar cluster (Ga 2As 2). We perform an ab initio all-electron self-consistent-field calculation to determine the electronic and structural properties of the cluster and the probe atoms (Na, Al, As and Cl) that are supposed to react with it. The predictions based on the HSAB principle are compared against total energy calculations of the system (atom + cluster) in configurations where we expect the reaction to initiate. The results encourages one to apply this method to a large variety of problems that involve chemical reactions of complex systems.