Abstract: C/P binary clusters were produced by direct laser ablation of C/P mixed sample on a time of flight mass spectrometer. These clusters can be divided into two groups, C/Pbinary clusters and pure carbon clusters. The intensity of pure carbon clusters became stronger with the increase of Pin mixed sample, which indicates that Phas an important influence on the formation of pure carbon clusters. In C/Pbinary clusters, the compositions of the positive ions are only C_n P₂⁺(0< n <30), C_n P₃⁺(0< n <22), while the negative ions are more abundant than positive ions, which have compositions of C_n P^-(0< n <20), C_n P₂^-(0< n <30), C_n P₃^-( n is even number in 2—30), C_n P₅^-( n is even number in₂—20), but no C_n P₄^- was produced. The photodissociation of C_n P₂⁺ indicates that their main photodissociation channel was the loss of one Patom. Combining photodissociation and DFTcalculations(B3LYP/631G^**), the most stable structure of C₆P₂ positive ions should be the linear chain structure with Patoms at each end of the molecule.

Key words: Laser ablation, C/P binary clusters, Time of flight mass spectrometry, Density, Function B3LYP