FTIR difference spectra of an irradiated coronene:water:argon matrix. The spectra are presented as difference spectra with respect to the deposited matrix, and represent total irradiation times of (a) one minute; (b) three minutes; and (c) eight minutes. Photoproduct bands are observed at the frequencies 1207, 1215 and 1221 cm^-1 and are attributed to oxygenated PAHs, as described in the text and tabulated in Table 1.