The electronic structures of the (1)A(1) ground state and several low-lying excited states of difluorodioxirane ( CF2O2) were investigated using the recently revised, multireference, second-order Generalized Van Vleck Perturbation Theory (GVVPT2) method for the description of electron correlation. Multiconfigurational self-consistent field calculations that included 19 molecular orbitals demonstrated that the electronic structures of all considered states are substantially multiconfigurational, with maximum configuration amplitudes not larger than 0.9. Equilibrium geometries of ground and first excited (1)A(1) states and the energetically lowest lying B-1 and B-2 triplet and singlet states were optimized at the GVVPT2 level. Additionally, the nature of and vertical excitation energy to the 1 (1)A(2) state are evaluated. Most of the considered states are predicted to be thermodynamically stable relative to their adiabatic dissociation limits and, at least some of them, should be observable in absorption spectra. The O-O bond lengths in the excited states are predicted to be significantly larger (1.94-2.34 Angstrom) than in the ground state (1.578 Angstrom), which contains the longest known bond of this type. (C) 2003 American Institute of Physics.