The optimized geometries, energies and harmonic vibrational frequencies of the doublet and quadruplet electronic states of O3- are theoretically predicted at the UHF/631+G*, MCSCF and CISD/MCSCF level. The geometry of the ground has Cs syrnmetry, and bond lengths of 1. 369 and 1.350Å, and a bond angle of 115.7° at the MCSCF level. The excitation energies for transitions 2A2←X2A", 2A’←X 2A" and 2B2← X 2A"I are 2.648, 1.372 and 1 .463 eV, respectively. For the quadruplet states of the ozonide anion the van der Waals complexes only are found. The intra-ionic charge transfers for the X2A", 2A’ and 4∑- states are investigated. The reactions 2A"→2B2→2A",2A’→ 2A1→2A’ and 4∑-→4∑g→4∑- have activation barriers of 1.281, 13.344 and 81.484 kcalīšmol-1, and rate constants of 3.254×1011 ,4.688×102 and 2.653×10-49 s-1, respectively.