Fig. 6

Optical absorption spectra of the chiral-icosahedral shells. The optical absorption spectra are computed from the time evolution of the electron density, over periods of 25 fs (low resolution, bold lines) and 250 fs (high resolution, fine lines) for a the I−Au₆₀ and b the I−Au₇₂. The insets expand the low-energy (0.5–2.0 eV) range, in order to highlight the distinct patterns of the I−Au₆₀ vs. I−Au₇₂ systems