Response of dopedHe4droplets

In the framework of a finite-range density-functional theory, we compute the response of ${}_{}{}^4{}_{}{}^{}\mathrm{He}_{\mathit{N}}^{}{}_{}{}^{}$ clusters doped with a rare-gas molecule. For this purpose, the mean field for the ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ atoms, their wave functions and effective quasiparticle interaction, are self-consistently calculated for a variety of particle numbers in the cluster. The response function is then evaluated for several multipolarities in each drop and the collective states are consequently located from the peaks of the strength function. The spectra of pure droplets approach those previously extracted with a similar algorithm resorting to a zero-range density functional. The spectra of doped clusters are sensitive to the presence of the impurity and are worth a future systematic investigation.