Internal excitation of CH3 radicals produced in the photolysis of acetone at 193 nm and the collisional enhancement of the infrared emission intensity in the ν3 spectral region

Fida Mohammad, Vernon R. Morris, A. Clay Jones, William M. Jackson

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Time-resolved IR emission spectroscopy has been used to monitor the fluorescence in the C-H stretch region of methyl radicals produced in the 193-nm photolysis of acetone. Spectra collected at 20-cm-1 resolution in the ν3 spectral region do not exhibit any structure. This indicates that the emission in this region is due to both the ν3 fundamental of CH3 and combination bands of the radical which overlap each other. Modes other than ν3(00n0) must contribute to the observed emission in the 3000-3350-cm-1 region. Translationally hot methyl radicals are also found to undergo very fast T → V energy-transfer processes via collisions with various noble gases, resulting in enhanced infrared emission. The intensity of the enhanced emission is a factor of 4 or 5 times the emission intensity in the absence of the noble gases, suggesting that most of the radicals are formed in other vibrational states. The results are explained by assuming that the CH3 radical is initially produced in a broad range of vibrational states.

Original languageEnglish (US)
Pages (from-to)6974-6978
Number of pages5
JournalJournal of physical chemistry
Volume97
Issue number27
DOIs
StatePublished - 1993
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physical and Theoretical Chemistry

Fingerprint

Dive into the research topics of 'Internal excitation of CH<sub>3</sub> radicals produced in the photolysis of acetone at 193 nm and the collisional enhancement of the infrared emission intensity in the ν<sub>3</sub> spectral region'. Together they form a unique fingerprint.

Cite this