One of the cluster behaviors observed in light nuclei such as 20 Ne and 44 Ti is the presence of an alpha particle rotating around a double magic number core. In this work, a theoretical method is used for investigation of rotational spectra of two-particle cluster states. To this end, Deng-Fan potential in addition to Hellman potential is used as the core and cluster potential. Next, given the Wildermuth condition, and proper quantum numbers describing the relative motion of the alpha particle and core, the rotational levels of 20 Ne and 44 Ti isotopes are calculated. Our studies show that the results are in good agreement with the available data.