ROTATIONAL PROPERTIES ASSOCIATED WITH HEITLER-LONDON MODEL OF H2

The first-order WBK approximation has been used to determine rotational constants Bv, and Dv, for the Heitier-London (HL) model of the H2 ground electronic state. Near-equilibrium characteristics of Bv and Dv, are discussed briefly in terms of the potential expansion about τ0. Over-all, the HL and experimental B v, curves have nearly the same shape. The HL Bv curve has negative curvature at all v converging at a slightly slower rate than the experimental curve at high v. This slower convergence is associated with the 1/r3 factor used in defining Bv. The HL Dv, curve, like the corresponding experimental curve, rises rapidly in the vicinity of dissociation. Both increases are attributed to a breakdown in the approximation that treats the centrifugal reaction term as a perturbation of the rotationless problem. The reliability of the first-order WBK approximation is checked and found to lead to only slight errors in the Bv, and D v, values.