Electronic State Coupling in the Photofragmentation of the SH molecule

Absorption of a photon can rupture a diatomic hydride, either directly, or through predissociation of a bound electronic state. The non-hydrogen fragment can appear in several fine-structure levels. The relative population of these atomic levels can reveal information about the coupling between the several repulsive states as the atoms recede.

We present an ab initio study of the SH(X²Π)→ SH(A²Σ⁺)→S(³P_J)+H reaction. We determined potential energy curves (PEC's) for the bound X and A states, and for the repulsive ²Σ^–, ⁴Σ^–and ⁴Π states, as well as the relevant spin-orbit coupling between the 18 individual states which correlate with S(³P_J)+H. A sophisticated time-independent method was used to simulate the photodissociation.

We shall compare our theoretical predictions with existing experimental results from the groups of Zhang (Riverside), Orr-Ewing (Bristol), and Parker (Nijmegen),