VUV-absorption cross section as a function of photon wavelength (bottom X-axis) and VUV-photon energy (top X-axis) of CO₂ ice deposited at 8 K, black solid trace. The blue dashed trace is the VUV-absorption cross-section spectrum of gas phase CO₂ adapted from Yoshino et al. 68. The fit, solid red dotted (single bands, see Table 2) and dashed-dotted trace, is the sum of two Gaussians. The inset figure is a CO₂ VUV-absorption cross-section close-up in the 124−129 nm range.