Quasimolecular α-like ground rotational bands were evidenced a long time ago in light nuclei, but they cannot be observed in heavy systems due to large Coulomb barriers. In order to search for rotational bands built on excited states in the heavy mass range, we investigate the shape of an α-nucleus quasimolecular potential matched to a realistic external α-daughter interaction by using as input data α-decay widths. It turns out that the Gaussian length parameter lies in a narrow interval and the equilibrium radius is slightly larger than the predicted Mott transition point from nucleonic to the α-cluster phase in finite nuclei, thus confirming that α clusters are formed on the nuclear surface at low densities. We point out that the α emitters above magic nuclei have the largest spectroscopic factors. In addition, we predict that for certain nuclei the first excited vibrational resonant state in the quasimolecular potential is close to the Coulomb barrier. Therefore, the rotational band built on it can be evidenced by the structure of the α-scattering cross section versus energy. Moreover, its detection by a highly sensitive γ-ray beam would provide an additional proof for the existence of α molecules in heavy nuclei.