A DENSITY-FUNCTIONAL STUDY OF THE ELECTRONIC-STRUCTURE OF SODALITE

We have conducted a first principles density functional theory (DFT) c alculation to explore the electronic structure of sodalite at various stages of Al-substitution. By calculating the electronic structure of both substituted and unsubstituted frameworks, with and without the pr esence of extra-framework atoms, we show that Al-substitution and cati on compensation essentially affect the electronic structure only at th e upper valence band edge (i.e., the frontier orbitals of reactivity t heory). In addition, we show that the equilibrium positions of the ext ra-framework cations are located in the vicinity of the frontier orbit als which are preferentially localized near aluminum. (C) 1998 America n Institute of Physics. [S0021-9606(98)00919-2].