The structure of large clusters such as neutral clusters, metallic clusters, and clusters ion is investigated. Furthermore, the electron distribution of large clusters when they are irradiated by an intense ultrashort laser pulse is treated. The cluster excitation results from the interaction of the electron subsystem with the laser field. Analyzing the quantum metallic cluster proves that its properties differ essentially from the properties of a classical small metallic sphere. The eigen frequency of the surface oscillation of a cluster is obtained and it is shown that it is lower than Mie frequency because of Thomas–Fermi screening.