Making Copper, Silver and Gold Fullerene cages breathe

We show that optical properties change when the fullerene structure of Au32, Cu32and Ag32inflates and deflates, as a little balloon. We first observe significant differences in the extinction spectra employing a classical approach based on the Green's dyadic method. By means of real-time time-dependent density functional theory, we calculate the optical spectrum under a δ-kick simulation, and the results are compared with the ground-state energetic properties, such as the HOMO-LUMO gap. A red-shift of the optical spectrum is expected as the fullerenes inflate, with only ± 10% change in the size as the fullerene breathing, a 0.8 eV shift in the first peak position could be observed in the gold nanoparticle. Ag has a smoother behaviour than Au and Cu. We have also found changes in the optical spectra can not be directly interpreted as a result of changes in the HOMO-LUMO gap.