Matrix isolation spectroscopy of Na atoms deposited as Na+ ions

The results of matrix isolation experiments of Na atoms deposited as Na+ ions in Ar matrices are reported. The optical absorption spectra include features which were observed for the first time in Na/Ar matrices prepared using laser ablation of Na metal [S. Tam and M. E. Fajardo, J. Chem. Phys. 99, 854 (1993)]. In that study, the observed novel trapping sites and improved atomic isolation efficiency were attributed to the high kinetic energy of the fast Na atoms produced by laser ablation. These new results challenge that interpretation and demonstrate that, at least for Ar matrices, the same effects can be reproduced by the deposition and subsequent neutralization of Na+ ions.