Comparative analysis of the influence of surface quantum effects on optical characteristics of alkali and noble metallic nanoparticles

The discrete sources method is used to develop a mathematical model for comparative analysis of the influence exerted on the optical properties of alkaline and noble metal nanoparticles placed in a dense outer medium when the bulk and surface quantum effects are taken into account. A substantial difference between the manifestations of the bulk and surface quantum effects in alkaline particles is demonstrated. Specifically, in the case of the bulk quantum effect, the surface plasmon resonance in alkaline particles exhibits a shift toward shorter wavelengths (blue shift), while the surface effect leads to a shift toward longer wavelengths (red shift). It is shown that this shift depends substantially on the outer medium density and can reach 50 nm in the spectral range.