Temperature dependence of the absorption spectrum of the methyl viologen cation radical and use of methyl viologen as a scavenger for estimating yields of the primary radicals in the radiolysis of high-temperature water

The absorption spectrum of the methyl viologen cation radical in an aqueous solution was measured as a function of temperature up to 200°C. The absorption coefficients at the two maxima, 605 and 395 nm, were both found to decrease with temperature, though the integral intensity of each of these bands remained almost constant. A pulse-radiolysis experiment, aimed at examining temperature dependence of the yield of hydrated electron, was made by using methyl viologen as a scavenger. The observed yield of the cation radical indicated that the G value of hydrated electron increases by about 28% upon temperature elevation from 20 to 200°C.