A resonancelike structure has been reported in the frequency spectrum of light emitted from small-particle tunnel junctions. Here we present a calculation of the frequency-dependent dipole moment and the radiation emission spectrum for a small particle located above a metal film. The dipole moment exhibits a resonance structure associated with a localized surface plasma mode at a frequency corresponding to the peak in the structure observed in the emission spectra.

• Received 2 October 1978

DOI:https://doi.org/10.1103/PhysRevLett.41.1746