Accurate dissociation energies from rotational predissociation and long-range forces: <i>B</i> 1Π LiH

Abstract

A new approach for determination of accurate dissociation energies from experimental predissociation data and the calculated long-range potential is described. In this case long-range predissociation in the rotational manifold of only a single vibrational level is required to yield a precise dissociation limit. The case of B 1Π LiH is considered in detail and a dissociation limit of 34 492.5 ± 0.5 cm−1 is obtained, 2.5 cm−1 lower and 4 times more precise than the best previous result. Also presented is a reasonably good representation of the potential energy curve for the B 1Π LiH molecule, constructed by an isotopically combined Rydberg-Klein-Rees method based on the concept of mass-reduced quantum numbers: η ≡ [ν+12]/μ and ξ≡J(J + 1)/μ.