Chemical Physics Letters, Vol.377, No.3-4, 419-425, 2003
Multiple ionization effects on the yields of HO2 center dot/O-2(center dot)- and H2O2 produced in the radiolysis of liquid water with high-LET C-12(6+) ions: a Monte-Carlo simulation study
Monte-Carlo simulations are used to investigate the effects of multiple ionization on the formation of HO2./O-2(.-) and 2 H2O2 in the radiolysis of water by C-12(6+) ions up to similar to430 keV/mum, at neutral pH and 25 degreesC. Taking into account the double and triple ionizations of water molecules, the primary yields G(HO2./O2.-) and G(H2./O2.-) are calculated as a function of linear energy transfer (LET). Our results quantitatively reproduce the large increase observed in G(HO2./O2.-) at high LET. They also simultaneously predict a slight maximum in G(H2O2) at similar to180-200 keV/mum, in excellent agreement with experiment. Under the conditions of this study, triple ionization is found to contribute only negligibly to G(HO2./O2.-). (C) 2003 Elsevier B.V. All rights reserved.