Revisited water radiolysis at elevated pH by accounting O₃^.- kinetics at low and high LET

Ozonide radical, O₃c^.-, is used in this study for probing radiolytic species formed in the radiolysis of liquid water at elevated pH. Its formation allows the scavenging of O^.- whereas its disappearing is due to its reactions with HO₂^- and O₂^.- . This article focuses on the formation and the reaction of O₃^.- at pH 13.2 by using pulse radiolysis technique, with 10 MeV electrons and 1 GeV C⁶⁺ ions beams for the first time. This allowed us to work with two different Linear Energy Transfer (LET) values (0.27 and 33 eV nm^-1 respectively), which means with two different primary distributions of radiolytic species. Consequently the rates constant of reactions O3^.- + HO₂^- and O₃^.- + O₂^.- could be revised with acceptable accuracy thanks to deterministic simulations: (1.1 ± 0.2) * 10⁶ M^-1 s^-1 and (1.5± 0.5) * 10⁷ M^-1 s^-1 respectively. Furthermore, the primary radiolytic yields of HO^./O^.- and H₂O₂/HO₂^- at high LET and pH 13.2 were estimated at 6.5 and 9.6 * 10^-8 mol J^-1 respectively which corresponds to the literature values. (authors)