An approximate {kappa} state solutions of the Dirac equation for the generalized Morse potential under spin and pseudospin symmetry

By using an improved approximation scheme to deal with the centrifugal (pseudo-centrifugal) term, we solve the Dirac equation for the generalized Morse potential with arbitrary spin-orbit quantum number {\kappa}. In the presence of spin and pseudospin symmetry, the analytic bound state energy eigenvalues and the associated upper- and lower-spinor components of two Dirac particles are found by using the basic concepts of the Nikiforov-Uvarov method. We study the special cases when {\kappa}=\pm1 (l=l=0, s-wave), the non-relativistic limit and the limit when {\alpha} becomes zero (Kratzer potential model). The present solutions are compared with those obtained by other methods. Keywords: Dirac equation, spin symmetry, pseudospin symmetry, generalized Morse potential,