A dispersive model of radical accumulation in irradiated solids

Radicals Produced by γ-Irradiation of Hyperquenched Glassy Water Containing 2′-Deoxyguanosine-5′-monophosphate

“…The results for HGW may be rationalized by assuming that for the low solute concentrations used in our study H-bonding between water molecules extends over relatively large distances, without interference by a solute, so that the OH · radicals recombine with each other via the mechanism of hydrogen transfer within the H-bonded structure, before they encounter a solute molecule. One may expect that in aqueous electrolyte glasses, due to high concentration of ions, the tetrahedral arrangement of water molecules is considerably distorted .…”

“…This is a rather unexpected observation, which contrasts those reported for liquid solutions of DNA constituents 46,49 where OH · undergoes addition to the double bond of the base or abstracts H atom from the sugar moiety and, in the case of thymine derivatives, from the methyl group. The products of such reactions were also reported for the irradiated 7 mol/dm 3 BeF 2 glass heated to about 140 K. 22,27 The results for HGW may be rationalized by assuming that for the low solute concentrations used in our study H-bonding SCHEME 1: Mechanism of Radical Formation at the L-type Defect Site in the Presence and in the Absence of dGMP between water molecules extends over relatively large distances, without interference by a solute, so that the OH · radicals recombine with each other via the mechanism of hydrogen transfer within the H-bonded structure, 16 before they encounter a solute molecule. One may expect that in aqueous electrolyte glasses, due to high concentration of ions, the tetrahedral arrangement of water molecules is considerably distorted.…”

“…Quantitative determinations were done by doubly integrating the spectra acquired at the microwave power of 0.02 mW, and a frozen solution of DPPH in benzene was used as a standard to evaluate the yields of radicals at 77 K, cf., ref 16 for details.…”