The use of the multiparameter generalized reduced-potential-curve (GRPC) method proposed in a previous article [F. Jenč, Phys. Rev. A 42, 403 (1990)] is tested on a group of eight alkali-metal diatomic molecules (for which the value of the depth of the minimum of the potential, ${\mathit{D}}_{\mathit{e}}$, and the potential up to the dissociation limit are known) in extending their ground-state potential from 45% up to the dissociation limit. For the repulsive limb, the one-parameter (α) GRPC approximation is satisfactory. Error limits of only 1–6 ${\mathrm{cm}}^{\mathrm{-}1}$ in energy for the attractive limb and less than 0.002 Å in the internuclear distance for the repulsive limb are obtained. The method may be used for an accurate prediction of the upper portion of the potentials (and the spectrum) of the remaining seven alkali-metal diatomic molecules where the molecular spectrum has not been measured [F. Jenč and B. A. Brandt, J. Mol. Spectrosc. 154, 226 (1992)].

• Received 9 July 1992

DOI:https://doi.org/10.1103/PhysRevA.48.1319