The potential energy surface (PES) of cyclic-N 3 for ground doublet electronic state to energy of 2A 2/ 2B 1 conical intersection , was analyzed. An adiabatic ground electronic state PES was constructed for a pure nitrogen ring molecule, which is based on extensive high-level ab initio calculations and accurate three-dimensional spline representation. Significant characteristics of PES were described by reduced dimensionality slices in internal hyperspherical coordinates and full dimensional isoenergy surfaces. The results show that remarkable geometric phase effects are predicted in spectra of rotational-vibrational states oc cyclic-N 3.