Dissociation of CH3SH+ by Collisional Activation: Evidence of Nonstatistical Behavior†

We have measured the absolute total cross sections for CH2SH+(CH3S+), CH2S+, HCS+, HS+, CH3+, and CH2+ produced by the collision-induced dissociation (CID) reaction of CH3SH+(12A‘‘) + Ar in the center-of-mass collision energy range of 1−36 eV. While the onset for CH3+ is consistent with the thermochemical threshold for the formation of CH3+ + SH, the onsets for other product ions are higher than their corresponding thermochemical thresholds. Using a charge transfer probing technique, we conclude that the m/e = 47 amu ions observed in the CID reaction have mostly the CH2SH+ structure. The relative yields for CH2SH+, CH2S+, HCS+, HS+, CH3+, and CH2+ formed in the CID reaction, which strongly favor the C−S bond scission process leading to the formation of CH3+ + SH, are significantly different from those measured in previous photoionization and charge exchange studies. Since the CH3+ + SH channel is not among the most stable product channels, this observation suggests that the collision-activated dissociatio...