Contributions from radiation damping and surface scattering to the linewidth of the longitudinal plasmon band of gold nanorods: A single particle study

Abstract

The scattering spectra of single gold nanorods with aspect ratios between 2 and 4 have been examined by dark field microscopy. The results show that the longitudinal plasmon resonance (electron oscillation along the long axis of the rod) broadens as the width of the rods decreases from 14 to 8 nm. This is attributed to electron surface scattering. Analysis of the data using γ = γbulk + AνF/Leff, where Leff is the effective path length of the electrons and νF is the Fermi velocity, allows us to determine a value for the surface scattering parameter of A = 0.3. Larger rods with widths of 19 and 30 nm were also examined. These samples also show spectral broadening, which is attributed to radiat..