The generation mechanism of silicon oxide–aluminum oxide compound clusters by laser ablation of siliceous materials

Abstract

The generation of silicon dioxide–aluminum oxide compound clusters under 308 nm XeCl excimer laser ablation of ZSM-5 zeolites with different SiO 2/Al 2O 3 ratios was studied by time-of-flight mass spectrometry. Two Al-containing cluster sequences [(SiO 2) n−1 (AlO 2)] − and [(SiO 2) n OAl] − are observed in the negative ion channel. Through the relationship between the abundance distribution of cluster sequences and the silicon aluminum ratio, the growth mechanism of [(SiO 2) n−1 (AlO 2)] − is discussed. Owing to the high electron affinity of AlO 2 compared to small (SiO 2) n clusters, AlO 2 is considered to be the core of growth of the compound cluster [(SiO 2) n−1 (AlO 2)] −.