Normalized IR reflectance spectra showing the thermal evolution of the CO₂ ν₃ doublet during warming of irradiated CaCO₃ from the 50 K, high-flux experiment. Dashed lines mark the fitted central wavelengths of the two components. The 4.27 μm feature weakens by 90 K and disappears by 150 K, while the sharper 4.25 μm component remains stable up to 120 K, then diminishes, but remains detectable after 3 hr at 150 K. This behavior aligns with the RGA data (Figure 4), which show a distinct CO₂ release peak around 90 K followed by broader desorption features above 110 K, and highlights multiple trapping states.