Abstract: The B3LYP method of density functional theory(DFT) is used to optimize geometry configuration,stability and frequency calculation of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) cation clusters at the level of 6-31G^*.Ground state of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) clusters are obtained.The geometry of clusters transforms from a planar structure to a spacial structure as cluster sizes of Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) are increased to 6 and 7,respectively.Among Ga_nN⁺(n=2~8) and Ga_nN₂⁺(n=1~7) cation clusters,Ga₄N⁺,Ga₆N⁺,Ga₃N₂⁺ and Ga₅N₂⁺ are stabler.

Key words: clusters, density functional theory(DFT), geometry structure, stability