Research Journal of Physics1819-3463xxxx-xxxxScience International10.3923/rjp.2010.160.164MohammadiS. 3201043Klein-Gordon equation is a useful quantum mechanical equation for a certain class of particles. A problem with this equation arises however in the probabilistic interpretation of its solutions as representing a single particle. The difficulty with the Klein-Gordon equation is that it has both positive and negative energy solutions. This can be shown to give rise to antiparticles which must be included for self consistency. The Klein-Gordon equation can be used to solve the pionic atom in a relativistically correct way; it is only appropriate for spin-0 particles and thus does not apply directly to electrons and the real hydrogen atom. It is useful for pionic (π) and kaonic (K) atoms. In this study with the help of Klein-Gordon equation, we used for the first time a simple model to obtain the energy levels of a pionic atom.]]>Friedman, E. and G. Soff,198511L37L37Gasiorowicz, S.,20033rd Edn.,pp: 336pp: 336Gilg, H., A. Gillitzer, M. Knulle, M. Munch, W. Schott and P. Kienle,2000207Pb formed in the 208Pb (d,3He) reaction. I. Experimental method and results.]]>62025201025201Greiner, W.,1990Hirenzaki, S. and E. Oset,20025276972Itahashi, K., K. Oyama, R.S. Hayano, H. Gilg and A. Gillitzer et al.,2000207Pb formed in the 208Pb(d,3He) reaction. II. Deduced binding energies and widths and the pion-nucleus interaction.]]>62025202025202Jackson, J.D.,19993rd Edn.,pp: 808pp: 808Robinett, R.W.,20062nd Edn.,Thornton, S.T. and A. Rex,20022nd Edn.,Toki, H. and T. Yamazaki,1988B213129129Umemoto, Y., S. Hirenzaki, K. Kume and H. Toki,2000C62024606024606Yamazaki, T., R.S. Hayano, K. Itahashi, K. Oyama and A. Gillitzer et al.,1998207Pb.]]>418246246