This form ensures the correct energy at the classical turning point, R σ , and the equilibrium geometry, R e (Figure ). The exponential parameters, ζ AB , were evaluated by fitting the potential energy curves of the reference molecules, H n A∼BH m (vide infra). The ROHF BE-BOP model describes the potential energy curves for pairs of monovalent atoms remarkably well, in spite of the improper dissociation of both the ROHF wave function and energy (Fig-