did not fit the experiment as well as for larger particles. This may be due to inelastic scattering of conduction electrons at the particle surface and/or to the large fraction of surface atoms. These effects increase with 1/d, changing the optical functions and the param-eters describing the free electron gas. As a result of that inhomogeneous broadening of the surface plasmon resonance and a reduced absorption in the long-wavelength range is observed.Calculations in the size range from 3 to 7 nm should, therefore, be considered as an estimate, and the models presented here should not be applied to particles smaller than 3 nm.