Electron transfer reaction between a simplified model molecule of α amino carbon centered radical and O 2 has been studied with ab initio calculations at the MP2/6 31++G ** //UHF/6 31++G ** level. The reactant complex and the ion pair complex have been optimized and employed to perform calculations of the reaction heat and the reorganization energy. Solvent effects have been considered by applying the conductor like screening model. Theoretical results show that the highly endothermic charge separation process, in which one electron transfers from the α amino carbon centered radical to O 2, so as to form an ion pair complex, is difficult to occur in gas phase. By applying an external electronic field to prepare the charge localized molecular orbitals, the charge separated state has been obtained using the initial guess induced self consistent field technique. The theoretical investigations indicate that the solvent effect in the process of the oxidation of α amino carbon centered radical by O 2 is remarkable. From the rate constant estimation, it can be predicted that the oxidation of the model donor molecule by O 2 can proceed, but not very fast. A peroxyl radical compound has been found to be a competitive intermediate in the oxidation process. Electron transfer reaction between a simplified model molecule of α amino carbon centered radical and O 2 has been studied with ab initio calculations at the MP2 / 6 31 ++ G ** // UHF / 6 31 ++ G ** level. The reactant complex and the ion pair complex have been optimized and employed to perform calculations of the reaction heat and the reorganization energy. Solvent effects have been considered by applying the conductor like screening model. Theoretical results show that the highly endothermic charge separation process, in which one electron transfers from the α amino carbon centered radical to O 2, so as to form an ion pair complex, difficult to occur in gas phase. By applying an external electronic field to prepare the charge localized molecular orbitals, the charge separated state has been obtained using the initial guess induced self consistent field technique. The theoretical investigations indicate that the solvent effect in the process of the oxid a rate of α amino carbon centered radical by O 2 is remarkable. From the rate constant estimation, it can be predicted that the oxidation of the model donor molecule by O 2 can proceed, but not very fast. A peroxyl radical compound has been found to be a competitive intermediate in the oxidation process.