Revisited water radiolysis at elevated pH by accounting O3˙− kinetics at low and high LET. Issue 108 (20th October 2015)

• Record Type: Journal Article
• Authors: El Omar, A. K.; Baldacchino, G.; Monnet, I.; Bouniol, P.
• Is Part Of: RSC advances. Volume 5:Issue 108(2015)
• Page Start: 89244
• Page End: 89253
• Publication Date: 2015-10-20
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra16858a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Recordings of O3 ˙ − formation and decays under low and high LET radiations and at pH 13.2 allowed revisiting the rate constants of its reactions with O2 ˙ − and HO2 − . Abstract : Ozonide radical, O3 ˙ −, 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 C 6+ 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) × 10 6 M −1 s −1 and (1.5 ± 0.5) × 10 7 M −1 s −1 respectively. Furthermore, the primary radiolytic yields of HO˙/O˙ − and H2 O2 /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.