Abstract: Based on the relativistic effective cores potential (RECP/SDD) for Pd atom and AUG-cc-pVTZ basisfunction for N atom, the structures of PdN and PdN2 have been optimized using B3LYP method. The results show thatthe ground state of PdN is 4[SIGMA]- and the ground state of PdN2 is C[infinity]V symmetry and 1[SIGMA]+ state. The Murrell-Sorbie potential energy function of PdN molecule has been fitted through the least square fitting, and the potential energy function of PdN2 is given by many-body expansion theory. The potential energy curves describe the structure character of PdN and PdN2 ground state molecules rightly, which details the inner transfer process of Pd. There is a saddle of C2V structure(RNN=0.11700 nm, RPdN=0.22088 nm). The energy barrier of inner transfer is 0.5197 eV, which is close to the calculated value of 0.4560 eV.

Key words: PdN, PdN2, Density functional method, Relativistic effective core potential(RECP), Many-body expansion potential energy function