Combining Rival pi-Space Descriptions of O3 and of SO2

Two rival solutions have emerged from applications of spin-coupled (SC) theory, also known as the full-generalized valence bond (full-GVB) approach, to the pi system of O3. The lowest solution (SCd) corresponds to significant diradical character but there is a second solution (SCc) which lies fairly close in energy. Combining these two descriptions, it turns out that both of them make significant contributions, with neither being dominant. The situation is entirely different for SO2, with the SCc description being overwhelmingly dominant over SCd. It can be concluded from an examination of various combinations of rival pi-space descriptions for both molecules that neither of the SCc nor SCd solutions provides a very satisfactory description on its own of the pi system in O3, but that SO2 is already fairly well described by SCc before the explicit incorporation of any SCd character.