Quantum approach to light scattering by a charged dust grain

Summary  We analyse on a theoretical basis the validity of the assumption that, for grains whose dimensions are comparable to the incident wave-length, the contribution to the light scattering of induced multipoles is dominant, the contribution of charge and other static multipoles being negligible. We suppose that the dust particle is a target of arbitrary high spin. Then we calculate the differential cross-section in the approximation of the low-energy limit up to quadratic order in the photon energyω. From this expansion we show that the term of Thomson scattering (of orderω 0 and the terms of orderω 2 are small compared with the Rayleigh scattering and the radiation by electric multipoles of orderl ⩾ 2 for grains of radius about 10-5 cm in the visible region.