  The ground-state electronic and structural properties, and the electronic
excitations of the lowest energy isomers of the Ag$_8$ cluster are calculated
using density functional theory (DFT) and time-dependent DFT (TDDFT) in real
time and real space scheme, respectively. The optical spectra provided by TDDFT
predict that the D$_{2d}$ dodecahedron isomer is the structural minimum of
Ag$_8$ cluster. Indeed, it is borne out by the experimental findings.
