Size dependent electron dynamics in silver nanoparticles

Summary form only given. Reduction of the size of a material to a nanometric scale leads to drastic modifications of its properties. In metallic systems, they are largely conditioned by the alteration of the conduction electron scattering processes whose study is thus of both technological and fundamental interests. Time-resolved femtosecond techniques have been shown to be powerful tools for their investigation in bulk material and have been recently applied to metal nanoparticles, yielding information on the size dependence of electron-phonon and electron-surface scattering. The impact of confinement on electron-electron scattering, and on the correlated internal thermalization dynamics of the electron gas, has however not been addressed. It has been shown in noble metal films that these can be studied by monitoring the transient optical property changes in the interband transition region, induced by creation of a nonequilibrium electron distribution using a femtosecond pulse. We have extended this technique to nanoparticle materials to study the effect of confinement on electron-electron scattering.