Computational method cover both static and dynamic situations,the computer time and other resources(such as memory and disk space) increase rapidly of the system being studied.This methods range from very  approximate to highly accurate;the latter are usually  feasible for small systems only.By studying this topic one can explore the structural evolution of neutral as well as negatively charged gas-phase metal nano clusters . We   studied computationally how this size-dependent geometric change  (from the bulk)relates to the  size-dependence of other    properties of large metal clusters,including their activity. Catalytic properties of clusters,especially  oxidation of  organic substrates have been examined.Computational insights have given reasons for their stability and unusual  properties.The molecular nature of these materials is un  equivocally manifested in a few recent studies such as  inter cluster reactions forming precise clusters. These   systems manifest properties of the core, of the ligand-shell,as well as that of the integrated systems.The study  of gas phase Au and Ag clusters was initiated in the 1960s.The interest in clusters arises,in part, because they constitute a new type of material which may have  properties   which are distinct from those of individual atoms and molecules or bulk matter. An important reason   for  interest in clusters is the size-dependent evolution of   their properties,such as their properties.In fact, both the geometric shape and the energetic stability of clusters may drastically change with size.