Predissociation in the spectrum of OH; a reinterpretation

Abstract

The weak predissociation in the v=1 and 2 levels of A ² Sigma ⁺, previously attributed to a ² Sigma ^- state crossing on the inner limb of the potential curve of A ² Sigma ⁺, has been reexamined assuming crossing on the outer limb. It can be accounted for either by a ⁴ Pi state or by a ⁴ Sigma ^- state, of which the latter seems more probable. This can account for the different strengths of lines from the F₁ and F₂ components of A ² Sigma ⁺.