Lines of g-Isopropanol and the model for its upper limit in red dashed lines (1.5 × 10¹⁶ cm⁻²). Gray is the data and cyan is the total fitted model from the detected and tentatively detected species. The vertical dotted lines show the transition frequency of each line. The E_up and A_ij are printed in the top left of each panel. The line that was used to find the 3σ upper limit is indicated by an “X” in the top right. The horizontal dashed lines show the 3σ level. Only lines with A_ij > 10⁻⁶ s⁻¹ and E_up < 300 K are shown.