Detection of quantum confined states in au nanoclusters by alkali ion scattering

Charge state-resolved time-of-flight spectra were collected for 2.0 keV 23Na+ scattered from Au nanoclusters deposited on TiO2(110). The neutral fraction of Na scattered from metallic Au is low ( approximately 3%), but it is surprisingly high (up to 50%) for small clusters. The results demonstrate that alkali ions couple to electronic states specific to the nanoclusters, and that the energy of the states is a function of the nanocluster size. This technique provides a new method for the spectroscopy of nanomaterials.