[en] Relative lifetimes and energies above the dissociation limit have been determined for the rotational predissociation of several quasibound levels of the X1Sigma+ state of 4HeH+. In particular the lifetimes are very sensitive to the shape of the potential energy curve. These measurements are used to discriminate between two ab initio potential curves which differ by only 0.00004 a.u. (about 1 meV). Using the lifetime data, relative population factors were determined for the observed levels.