  We develop a microscopic model for fluorescence of a molecule (or
semiconductor quantum dot) near a small metal nanoparticle. When a molecule is
situated close to metal surface, its fluorescence is quenched due to energy
transfer to the metal. We perform quantum-mechanical calculations of energy
transfer rates for nanometer-sized Au nanoparticles and find that non-local and
quantum-size effects significantly enhance dissipation in metal as compared to
those predicted by semiclassical electromagnetic models. However, the
dependence of transfer rates on molecule's distance to metal nanoparticle
surface, $d$, is significantly weaker than the $d^{-4}$ behavior for flat metal
surface with a sharp boundary predicted by previous calculations within random
phase approximation.
