Unimolecular reaction pathways for the 2-(dimethylphosphatoxy)-2-(p-methoxyphenyl)-1,1,-dimethylethyl radical 1 have been studied with several different hybrid density functional methods. The most reliable prediction has been obtained through combination of relative energies calculated at the BHLYP/6-311+G(d,p)// Becke3LYP/6-31G(d) level of theory with solvation free energies calculated with the PCM (polarizable continuum) model for THE All reaction pathways characterized in detail have mixed homolytic/heterolytic character with a dominating heterolytic component. Concerted reaction pathways for 1,2- and 3,2-migration of the phosphate group lead to rearranged benzylic radical 2 that is more stable than 1 by about 30 kJ/mol. Also, a flat region of the potential energy surface has been identified that contains intermediates of nonintegral charge separation. This region of the potential energy surface can be reached from the reactant radical 1, the rearranged radical 2, and the phosphoric acid elimination products 11 and 12. The intermediates located on this part of the potential energy surface can best be described as contact radical ion pairs based on their overall geometrical structure. However, the phosphate group charges never exceed a value of -0.75 even in THF solution. The absolute reaction barriers are strongly influenced through the presence of a solvent reaction field even for a low-polarity solvent such as THF and thus show the expected behavior for a charge-separating reaction type. The gas-phase UV-vis excitation spectrum calculated for contact radical ion pairs using the adiabatic TDDFT approximation features a very long wavelength absorption between 900 and 1000 nm absent in the spectrum of the underlying radical cation whose longest wavelength absorption is predicted to be at 555 urn. The results of the TDDFT computations have been confirmed by coupled-cluster calculations employing the CC2 approximation.