Equivalent width contribution function (flux) of weak (W ≤ 0.5 pm) artificial molecular lines of CO, CN, CH, C₂, NH, OH (top left to bottom right) with lower level excitation potential χ = 0 eV in the full 3D, average ⟨3D⟩, and 1D model atmospheres with metallicity [M/H]  = −3.0. Contribution functions were normalized to the equivalent width of the line computed using 3D models.