THEORETICAL-STUDY OF THE GROUND AND EXCITED-STATES OF OZONE IN ITS SYMMETRICAL NUCLEAR ARRANGEMENT

Potential energy surfaces for the ground state X1A1 and the first twelve states of the ozone molecule have been determined for the symmetric arrangement of nuclei employing the multireference configuration interaction (MRD-CI) treatment in a [6s, 4p, 1d] + [1s(b), 1p(b)] contracted Gaussian basis. Calculations were carried out for a two-dimensional grid of points varying the internuclear angle gamma and the bond length R to obtain the optimum geometrical parameters R and gamma for all states treated. Special emphasis was placed on the interaction of states. The well-known double minimum potential of the X1A1 state in the symmetric arrangement of nuclei is computed. The 2(1)A1 state, possibly responsible for the weak absorption in the Huggins band (3.44-4.13 eV), is found to exhibit a double minimum outside of the Franck-Condon region suggesting that a vertical transition reaches the repulsive branch of the potential. The transition moments from the ground state to the three lowest electronic states are also presented for many grid points. The lowest 1 3A2 and 1 B-3(2) states are found to have an adiabatic excitation energy (0.86 and 1.10 eV, respectively) below the dissociation energy (D(e) = 1.13 eV). The high-lying triplet state 2 B-3(1) also shows a double minimum, whereby the absolute minimum occurs at linear geometry. The minimum energy paths for C2v dissociation in the X1A1 state in higher states (at the X1A1 optimized geometrical values) are calculated; their correlation to the C2v dissociation channels is discussed.