Since the optical functions of gold are dependent on the particle
size for particle sizes smaller than the mean free path in bulk
gold, we have corrected n for the influence of a reduced mean
free path of the conduction electrons. This was done in the
framework of the extended Drude model following the arguments
brought forward in ref 17. In brief, the complex dielectric constant
( ) n2) is split into contributions from the bound electrons (B1
and B2) and contributions from the free electrons (A1(R) and A2-
(R)) according to eq 5. These contributions are shown in Figure 2