CHAOS, INTERACTIONS, AND NONEQUILIBRIUM EFFECTS IN THE TUNNELING RESONANCE-SPECTRA OF ULTRASMALL METALLIC PARTICLES

We explain the observation of clusters in the tunneling resonance spec tra of ultrasmall metallic particles of a few nanometer size. Each clu ster of resonances is identified with one excited single-electron stat e of the metal particle, shifted as a result of the different nsnequil ibrium occupancy configurations of the other single-electron states. A ssuming the underlying classical dynamics of the electrons to be chaot ic, we determine the typical shift to be Delta/g where Delta is the si ngle particle mean level spacing and g is the dimensionless conductanc e of the grain.