PHYSICAL REVIEW A, vol.43, no.11, pp.5787-5789, 1991 (SCI-Expanded)
A different approach to the shifted 1/N expansion technique is developed to deal with the Klein-Gordon particle trapped in a spherically symmetric potential. Properly modifying the definition of the perturbative expansion of the energy eigenvalue, and without making any approximation in the determination of the parameters involved, we obtain sufficiently good results compared with the exact ones for the Coulomb problem. The calculations are carried out to the second-order correction of the energy series.