Photochemical transformations in ice Implications for the fate of chemical species

A quantum yield of •i•e = 2.3 x 10 '4 (+_ 4 X 10 -•) was determined for the photochemical degradation of 4nitrophenol over the wavelength range of 300 to 370 nm in ice pellets (pH 5.6). Five reaction products were identified: hydroquinone, benzoquinone, 4-nitrosophenol, nitrate, nitrite, and the likely formation of organic polymers. The similarities of these results to the observations from 4-nitrophenol photolysis in aqueous solutions indicate that similar mechanisms are operative in both phases. The photochemical decomposition of 4-nitrophenol under conditions similar to those in polar snow and ice suggests that other direct and indirect photochemical process can occur in the polar ice/snow during spring and summer.