On dissipative effects in volume plasmon response

We study the imortance of dissipation on the volume plasmon response in moderate size Sodium clusters. Volume plasmon response has been tentatively identified experimentally in Sodium clusters. An open question is whether the standard mean-field approach, based on Density Functional Theory (DFT), is sufficient to provide a proper description of such modes in a possibly non-linear regime of excitations. A conceptually simple approximation, based on a recently proposed quantum Relaxation Time Ansatz (RTA), is used to evaluate these effects. It turns out that the response is, in the explored cases, clearly dominated by the mean field, which allows the use of simplified theories that give access to larger systems.