Top panel: our fitting result of the Eu line for Arcturus. The dotted black line shows the observed spectrum; the solid red line shows the best-fit spectrum; and the dashed gray line shows the spectrum without Eu contribution. Bottom panel: our fitting result of the Th line in Arcturus. The dashed blue lines show the synthetic spectrum before the adjustment of the line list; the solid red line shows the final fitting result; and the dashed gray line shows the synthetic spectrum without Th contribution.