Computational Study of Extraframework Cu+ Sites in Ferrierite: Structure, Coordination, and Photoluminescence Spectra

Abstract

The interaction of the Cu+ ion in the lowest 3d10 singlet and 3d9s1 triplet states with the ferrierite matrix is studied computationally by means of a combined quantum mechanics/interatomic potential function technique. The excitation and emission energies found for the Cu/ferrierite and Cu/ZSM-5 systems are very similar. The 540 and 480 nm peaks in the photoluminescence emission spectra are assigned to the Cu+ ion located on the channel intersection and on the walls of the main or perpendicular channels, respectively. The structure and coordination of individual binding sites of Cu+ in ferrierite are very similar to those found in ZSM-5. Contrary to ZSM-5, the sites on the wall of the main and perpendicular channels of ferrierite are more stable than the sites located on the channel intersection. Therefore, the population of the sites on the channel intersection will be lower in ferrierite than in ZSM-5. It is suggested that the differences in populations of sites on the channel intersection found for ZS...