On spin-forbidden processes in the ultra-violet photodissociation of ozone

We have calculated one-dimensional potential cuts of twenty-five singlet/triplet A′/A″ states of ozone. The calculations are performed at the multi-reference configuration interaction level of electronic structure theory with the aug-cc-pVTZ set of atomic basis functions. It is found that many triplet potentials cross the 31A′(1B2) potential, on which the fragmentation after excitation in the Huggins–Hartley band system primarily proceeds. These crossings allow the population of the three spin-forbidden product channels O(3P)+O2(a1Δg), O(3P)+O2(b1Σg+) and O(1D)+O2(X3Σg−). Possible consequences of singlet–triplet crossings for the Wulf band are also briefly discussed.