THE LOWEST EXCITED 1A2 AND 1B1 STATES OF OZONE - 2 CONICAL INTERSECTIONS AND THEIR IMPACT ON PHOTODISSOCIATION

We report results of ab initio configuration-interaction calculations on the lowest excited 1A2 and 1B1 states of ozone near their C2-upsilon minima and also at several nearby C(s) geometries, where these two states become the lowest 1A" states. We find that in C2-upsilon symmetry these two states have a seam intersection very near the 1B1 minimum which becomes a conical intersection for small distortions to C(s) geometries. The influence of this intersection on the Wulf and Chappuis bands of ozone is discussed and a new interpretation of these bands is presented. We also demonstrate the existence of a second conical intersection involving these same two states for D3h symmetries, where they become degenerate components of a 1E" state.