FIG. 3.
Infrared spectra (4000–850 cm−1) showing the differences of absorbance (relative to the spectra before irradiation) for the three H2O:pyrimidine ice samples (1000 ML) irradiated with (a) the 0th order beam light for 2, 10, 30, 60, and 130 min; (b) the He i line for 2, 10, 35, 80, and 160 min; and (c) the He ii line for 2, 11, 25, 60, and 130 min. The identified photo-products are indicated on the spectra according to the positions of their respective bands.