Spectral extracts showing the effect of coupling parameters. The dot dash lines are predictions without coupling parameters; the dashed lines show predictions with coupling parameters from Müller et al. (2016) and the solid lines show predictions with additional coupling parameters determined in this work. Lines for other identified transitions are shown in the figures as well: • for ground state of a-n-PrCN, for v₃₀ = 1 of a-n-PrCN, ° for v₃₀ = 1 of g-n-PrCN, and × for v₂₉ = 1 of g-n-PrCN.