Applying the probe molecule strategy, surface-enhanced Raman spectroscopy h
as been used, for the first time, as a diagnostic tool of the electronic pr
operties of metal nanorods; the vibrational frequency of the probe molecule
SCN- at Cu nanorods is shown to critically depend on the nanorod's diamete
r in the range from 50 to 15 nm; the up-shifting of the Fermi level with a
decrease of the nanorod's diameter is interpreted based on the change of co
hesive energy owing to the high ratio of surface to bulk atoms.