Theoretical studies of [Si4NO](-) clusters with ab initio MO and DFT methods

Various isomers of[Si,NO](-) cluster have been studied at both UHF/6-31G* a nd UB3LYP/6-31G* levels. The optimized structures and harmonic vibrational frequencies were calculated at both levels of approximations. Two obviously different groups of isomers have been found as in the case of[Si4NO](+), a nd the Si, cluster shows higher reactivity toward NO molecule than Si-4(+). The differences between anionic and cationic Si,NO clusters and the compar ison with the experimental results were discussed. (C) 1999 Elsevier Scienc e B.V. All rights reserved.