Observed (blue) and simulated (red) NH₂D spectra towards (0,0). Left: simulations from the PH model with two different sets of model parameters. Right: results from the FS model with the same parameter values. The model parameters are given at the top of each panel. The upper plot in each of the four panels shows the 1₁₁ − 1₀₁ lines and the lower plot shows the 1₀₁ − 0₀₀ lines of oNH₂D and pNH₂D. The para-lines are shifted downwards for clarity.