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2014
ACL
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A.Balcerzyk, I.Boughattas, S.Pin, E.Balanzat, G.Baldacchino, 'First observation of HO center dot reactivity in water under high energy ions at elevated temperature', Phys. Chem. Chem. Phys. 16 23975-23984 (2014) doi:10.1039/c4cp03049d
This communication reports the first observation of the formation of HO center dot produced under two different High energy ion beams, O-18(8+) and Ar-36(18+) having Linear Energy Transfers (LET) of 65 and 350 eV nm(-1) respectively, at temperatures up to 411 K. Both scavenging with various concentrations of SCN- and heavy-ion pulse radiolysis methods are used with an original temperature and pressure regulated optical cell. Deconvolution of kinetics is used to analyze the evolution of HO center dot track segment yields as a function of time and temperature. It takes care of involving the ionic strength effect and Arrhenius expression in the rate constants correction. The results show a fast decay of HO center dot yields in the 10(-10)-10(-8) s range which denotes an efficient reactivity of this species in the track structure of the ion beam. This effect is enhanced with the lowest LET of O8+. Increasing the temperature also accelerates the decays for both ions. These observations are discussed in terms of temperature activation of reactions and the track structure exhibiting the formation of HO center dot in a "low LET" penumbra around the ionization tracks. HO center dot track segment yields at 100 ns, of 0.4 x 10(-7) and 0.6 x 10(-7) mol J(-1), respectively for 350 and 65 eV nm(-1), are not affected by temperature.
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