Theoretical study of the homolytic photolysis of hydrogen peroxide at the state-of-the-art level

• For the first-time, we calculated the potential energy curves of the low-lying excited states of H2O2 at the MS-CASPT2//CASPT2 level.
• The photolysis pathways of H2O2 at 308–465 nm was assigned by theoretical study for the first time.
• The solvent effect was considered in the homolytic photolysis of H2O2.
• Cleared the previous equivocality and gave a whole picture of the homolytic photolysis of H2O2.

A thorough investigation on the homolytic photolysis of hydrogen peroxide (H2O2) is helpful for understanding many reactions in biochemistry and environmental chemistry. There is still debate regarding this reaction's mechanism, although many types of experimental and theoretical studies have been performed. High quality potential-energy curves (PECs) are necessary to deduce the dissociation mechanism. In the current study, the PECs of H2O2 with respect to the OO bond distance for the ground state and the low-lying excited states are calculated using multistate second order multiconfigurational perturbation theory. The vertical excitation energies and the dissociation energy of H2O2 are predicted at a high computational level. The current study is able to assign homolytic photolysis pathways of H2O2 observed experimentally at three regions of incident wavelength. The solvent effect is also considered in this study.

Figure optionsDownload as PowerPoint slide