The position of the plasmon band is experimentally known to be strongly influenced by the size and structural geometry of the noble metal nanocluster. Figure starts by exploring the so-called size effect. More precisely, it depicts how the different exchange-correlation approximations succeed to reproduce the experimental shift of the plasmon band when the size of the system increases. For this purpose, it compares the UV/vis photo-absorption spectrum of two other silver clusters in tetrahedral symmetry (i.e., Ag 20 and Ag 4+ 56 ) to the one of Ag 120 . Ag 20 cannot be considered as a nanoarchitecture since its size reaches only 0.85 nm. However, with a size of 1.38 nm, Ag 4+ 56 can be. Their maximum of absorption are experimentally measured at 3.83 and 3.90 eV, respectively, while it is of about 3.73 eV for Ag 120 . When the size of the cluster increases, a blueshift followed by a redshift of the plasmon band is thus observed.