Abstract We present the solutions of the ro‐vibrational motion of a diatomic molecule with a spatially dependent mass by solving the Dirac equation with position‐dependent mass for repulsive vector
V(r) and attractive scalar
S(r) q‐deformed Morse potential for any
κ value, within the framework of Pekeris approximation of the spin‐orbitcoupling term. The relativistic energy spectra are obtained using theNikiforov‐Uvarov method and the two‐component spinor wavefunctions are obtained in terms of the Laguerre polynomials. It is found that there exist only negative energy states for bound states, and the energy values for a fixed value of
nr increase with decrease in
κ . © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012