The equilibrium geometry of PuN and PuN2 molecule have been firstly calculated on the computational levels of density functional theory (DFT) with the relativistic effective core potential and the valence basis sets. The possible electronic state and reasonable dissociation limit for the ground state of PuN and PuN2 molecule are determined based on atomic and molecular reaction statics. Murrell-Sorbie analytic potential energy function of PuN molecule has been derived to be fitted to ab initio data through the least-square fitting, and harmonic frequency, force constant and spectroscopic data have been derived for the first time. The analytic potential energy function of molecule is derived by many-body expansion theory.

Key words: PuN, CONFIGURATION, POTENTIAL ENERGY