Surface collective excitations in ultrafast pump-probe spectroscopy of metal nanoparticles

Academic Article

Abstract

  • The role of surface collective excitations in the electron relaxation in small metal particles is studied. It is shown that the dynamically screened electron-electron interaction in a nanoparticle contains a size-dependent correction induced by the surface. This leads to new channels of quasiparticle scattering accompanied by the emission of surface collective excitations. In noble-metal particles, the dipole collective excitations (surface plasmons) mediate a resonant scattering of d-holes to the conduction band. The role of this effect in the ultrafast optical dynamics of small nanoparticles is studied. With decreasing nanoparticle size, it leads to a drastic change in the differential absorption lineshape and a strong frequency dependence of the relaxation near the surface plasmon resonance. The experimental implications of these results in ultrafast pump-probe spectroscopy are addressed. We also discuss the size-dependence of conduction electron scattering rates.
  • Authors

    Published In

  • Chemical Physics  Journal
  • Digital Object Identifier (doi)

    Author List

  • Shahbazyan TV; Perakis IE
  • Start Page

  • 37
  • End Page

  • 49
  • Volume

  • 251
  • Issue

  • 1-3