Absorption of low-frequency radiation by small metal particles: a semiclassical random-phase-approximation

Calculations of low-frequency absorption of electromagnetic radiation by sm all conducting particles must take account of screening of the externally a pplied field due to polarization charges. In this paper we introduce a 'sem iclassical' variant of the random-phase-approximation (RTA) method for obta ining the self-consistent held. Electric and magnetic dipole absorption are treated within a unified scheme, and we also demonstrate the equivalence o f this approach to a superficially dissimilar perturbative method. Thr appr oach is more tractable than the full RPA equations, and allows us to discus s the effective potential for both diffusive and ballistic electron dynamic s.