A quantum mechanical analysis on the selective production of the oxygen atom fine-structure states along asymmetric resonances in OH predissociation

Predissociation of the A 2Σ+ state is treated by an exact theory employing two frame transformation matrices, each of which connects the atomic term limits (O(3P) and O(1D)) to the correlating adiabatic Born—Oppenheimer states. Resonances corresponding to the higher (v ⩾ 7) rovibrational levels of the A 2Σ+ state are predicted to have asymmetric (Fano-type) profiles. The branching ratios of O(3Pj, j = 0, 1, 2) are shown to be influenced by nonadiabatic interactions in the Franck—Condon region between the A 2Σ+ and dissociative 4Σ−, 2Σ− and 4Π states. The branching ratios show a strong variation along asymmetric resonances, while remaining energy independent along Lorentzian resonances.