  Dirac equation for a charged particle in static electromagnetic field is
written for special cases of spherically symmetric potentials. Besides the well
known Dirac-Coulomb and Dirac-Oscillator potentials, we obtain a relativistic
version of the S-wave Morse potential. This is accomplished by adding a simple
exponential potential term to the Dirac operator, which in the nonrelativistic
limit reproduces the usual Morse potential. The relativistic bound states
spectrum and spinor wavefunctions are obtained.
