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 3(1)A'(B-1(2)) 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(P-3) + O-2(a(1)Delta(g)), O(P-3) + O-2(b(1)Sigma(g)(+)) and O(D-1) + O-2(X(3)Sigma(g)(-)). possible consequences of singlet-triplet crossings for the Wulf band are also briefly discussed. (C) 2003 Elsevier B.V. All rights reserved.