Fig. 3.

Comparison of (a) LSP resonance frequencies ${\omega }_l^{\prime }\left(R\right)$ and (b) damping rates ${\omega }_l^{\mathrm{\prime \prime }}\left(R\right)$ calculated vs radius for different models of the dielectric function; dashed lines: for ε _Di(ω, R); solid lines: for ε ^(Au)(ω, R) accounting for contribution of the frequency-dependent interband transitions over 1.8eV. n _out = 1.33 (water). Horizontal short-dashed lines (a) show the lower frequency limits: of the optical range (red line at 1.65 eV) and of the measured indexes of refraction [4] (black line at 0.64 eV (see Fig. 1)