The intersection seam between the 1(1)A' and 2(1)A' states of ozone

The intersection seam between the two lowest (1)A' states of ozone has been determined. The potential energy surfaces and the seam are calculated and discussed in perimetric coordinates which exhibit the full three-dimensional symmetry. The seam is shown to form a closed curve which crosses the C-2v-restricted coordinate planes at six points. Three of these correspond to the previously determined intersection, the starting point of the present search. The other three correspond to highly repulsive regions on the potential energy surface where two atoms approach each other to within two-thirds of the O-2 bond length. At the former three points both states have (1)A(1) symmetry, but at the latter three points one state has (1)A(1) symmetry whereas the other has B-1(2) symmetry. Consequently, there exist three additional branches of the intersection seam between these two states. Each of these branches lies entirely in one C-2v-restricted coordinate plane and connects to the previously discussed C-s-seam at one point. The existence of a further intersection seam is established. A novel method for determining intersection points is described.