Modified l-states of diatomic molecules subject to central potentials plus an angle-dependent potential

We present modified $\ell$-states of diatomic molecules by solving the radial and angle-dependent parts of the Schr\"odinger equation for central potentials, such as Morse and Kratzer, plus an exactly solvable angle-dependent potential $V_{\theta}(\theta)/r^2$ within the framework of the Nikiforov-Uvarov (NU) method. We emphasize that the contribution which comes from the solution of the Schr\"odinger equation for the angle-dependent potential modifies the usual angular momentum quantum number $\ell$. We calculate explicitly bound state energies of a number of neutral diatomic molecules composed of a first-row transition metal and main-group elements for both Morse and Kratzer potentials plus an angle-dependent potential.