Oxidation process of an Al micro-cluster

Quantum theoretical calculations have been performed to obtain the lowest energy reaction path for the oxidation of an Al micro-cluster with an O2molecule. In reactions with a ground state O2molecule spin triplet state., a very low potential energy barrier of 0.2 eV exists for the adhesion of an O2 molecule to an Al cluster and the stabilization energy of the final product is 3.0 eV. In reactions with an electronically excited O2 molecule spin singlet state., no energy barrier exists during the reaction and the oxidation of the Al cluster proceeds spontaneously, giving a stabilization energy of 7.7 eV. Since the ground electronic state of the initial reactant is the triplet state and the most stable final product is the singlet state, an inter-system crossing from the triplet to the singlet state is expected to occur during the oxidation process. q2000 Elsevier Science B.V. All rights reserved