Evolution of normalised column density of different photo products with increasing UV photon fluence. The normalisation factor is the column density of NH₂CHO before UV irradiation. The IR absorption area is obtained by Gaussian fitting, with one standard deviation used as an error bar. When the error bar is not visible, the error is within the size of the symbol. The best fit to the cumulative abundance growth of the total photo product (solid black line) is also shown. The estimated formation cross-section (σ_f) and asymptotic formation (a₂) are also reported. Similarly, the best fit to the growth curves (till F_UV = 3.7 × 10¹⁸ photons cm⁻²) of CO, OCN⁻, and HNCO is also shown.