The initial vibrational level distribution and relaxation of HCN[X 1+ (v1,0,v3)] in the CN(X 2+)+CH4→HCN+CH3 reaction system

G. A. Bethardy*, Frederick J Northrup, R. Glen Macdonald

*Corresponding author for this work

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27 Scopus citations


The reaction of the cyano radical (CN) with methane was studied by time-resolved infrared absorption spectroscopy by monitoring individual rovibrational states of the HCN and CH3 products. The initial vibrational level distribution of the bendless vibrational levels of HCN(v1,0,v3) was determined by plotting the time dependence of the fractional population of a vibrational level and extrapolating these curves to the origin of time. About 20% of the HCN products were observed to be initially produced in the HCN(v1,0,v3) vibrational levels, with v1 and v3=0,1,2. The CN radical was created by laser photolysis of three different precursors. Each photolyte provided a different initial vibrational level distribution of CN; however, similar initial HCN(v1,0,v3) vibrational level distributions were obtained independent of the CN radical precursor. This may indicate that the CN radical does not act as a spectator bond during the course of a reactive encounter for this system. The time dependence of. the CH3 (00000) ground state was also followed using time-resolved infrared absorption spectroscopy. Preliminary data indicates that a large fraction, if not all, the CH3 radicals are produced in their ground state in the title reaction.

Original languageEnglish (US)
Pages (from-to)4533-4549
Number of pages17
JournalJournal of Chemical Physics
Issue number11
StatePublished - Jan 1 1996

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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