Study of the dissociation of CH3SCH3+ by collisional activation : Evidence of nonstatistical behavior

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Y. J. Chen
  • P. T. Fenn
  • C. Y. Ng
  • Chi-Kin Law
  • Wai-Kee Li

Detail(s)

Original languageEnglish
Pages (from-to)9729-9736
Journal / PublicationJournal of Physical Chemistry A
Volume106
Issue number42
Publication statusPublished - 24 Oct 2002
Externally publishedYes

Abstract

The collision-induced dissociation (CID) reaction of CH3SCH3+ + Ar was studied in a triple-quadrupole, double-octopole ion-molecule reaction apparatus. The absolute total cross sections for the product ions CH2SH+/CH3S+, CH2S+, CHS+, and CH3+ formed in the CID reaction have been measured in the center-of-mass kinetic energy (Ecm) range of 1-19 eV. Using the charge-transfer probing technique, we found that mass-47 product ions are formed in both the CH2SH+ and CH3S+ structures. The onsets for CH2SH+, CH3S+, CH2S+, CHS+, and CH3+ are consistent with their thermochemical thresholds. The formation of the higher-energy product channel CH3S+ + CH3, which involves C-S bond scission, is found to dominate in the Ecm range immediately above its onset. The lower-energy channel corresponding to the formation CH3SCH2+ + H is not found. The strong preference observed for the higher-energy channel is in accordance with the conclusions obtained from the CID studies of CH3SH+ and CH3CH2SH+, providing further evidence that the CID of CH3SCH3+ is also nonstatistical. The high yield of CH3S+ + CH3 is attributed to the more efficient translational-to-vibrational energy transfer for the C-S stretching modes with lower frequencies than to those for the C-H stretching modes with higher frequencies, along with weak coupling between these vibrational modes with significantly different frequencies of CH3SCH3+. In addition, the dissociation pathways deduced are consistent with the results of ab initio calculations at the G3 level.

Citation Format(s)

Study of the dissociation of CH3SCH3+ by collisional activation : Evidence of nonstatistical behavior. / Chen, Y. J.; Fenn, P. T.; Lau, Kai-Chung et al.

In: Journal of Physical Chemistry A, Vol. 106, No. 42, 24.10.2002, p. 9729-9736.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review