Potential energy surfaces along different escaping paths of the nitrogen atom inside the neutral and charged endohedral fullerene N@C-60 have been constructed at the density functional theory level. It is found that the dispersion force plays an important role in determining the equilibrium geometry of the neutral system. The most energetic favorable escaping path is towards the center of C = C/C-C bond connecting two neighboring rings for all three systems. The rate determining potential energy surface shows a very small dependence on the charging state. The presented theoretical results should be useful for the practical applications of N@C-60 in quantum computing and information. (C) 2011 Elsevier B.V. All rights reserved.