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

We have calculated one-dimensional potential cuts of twenty-five singlet/triplet <f>A′/A″</f> 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 <f>31A′(1B2)</f> 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 <f>O(3P)+O2(a1Δg)</f>, <f>O(3P)+O2(b1Σg+)</f> and <f>O(1D)+O2(X3Σg−)</f>. Possible consequences of singlet–triplet crossings for the Wulf band are also briefly discussed. [Copyright &y& Elsevier]