TPD traces for key species obtained following exposure of toluene to a high H-atom fluence of 25.9 × 10¹⁸ cm⁻². (a) TPD trace for toluene (92 amu) in orange. (b) TPD traces on a different y-axis scale for partially hydrogenated toluene (parent mass 96 amu, main fragment 81 amu) in light blue and methyl-cyclohexane (parent mass 98 amu, main fragment 83 amu) in dark blue and cyclohexane (84 amu) in red. The cyclohexane desorbs over a range of temperatures starting from 160 K. (c) Shared QMS fragments of mass 55 and 56 amu that are fragments of the hydrogenated toluene species and cyclohexane.