Photofragmentation dynamics of acetone of 193 nm: State distributions of the CH3 and CO fragments by time- and wavelength-resolved infrared emission
Abstract
The photolysis of acetone at 193 nm is known to produce two methyl radicals and CO following excitation of a 1(n,3s) Rydberg transition. Vibrational excitation is detected in both products immediately following the dissociating laser pulse by observing the resulting infrared emission. Vibrational distributions are obtained for CH3(ν3) and for CO. These are, for CH3(ν3): v=1/2/3=0.73±0.05/0.14±0.05/0.13±0.05 and for CO: v=1/2/3=0.75±0.05/0.16±0.05/0.09±0.05. An approximate rotational temperature of 1500 K can be used to fit the CH3(ν3) emission spectrum. The CO is formed with very high, non-Boltzmann rotational excitation. This result strongly suggests that the three-body dissociation occurs via a two-step mechanism, rather than a rigorously concerted process. The high rotational excitation is most likely imparted by the kinematics in the breakup of a bent acetyl fragment.
- Publication:
-
Journal of Chemical Physics
- Pub Date:
- July 1986
- DOI:
- 10.1063/1.451289
- Bibcode:
- 1986JChPh..85..817D
- Keywords:
-
- Acetone;
- Carbon Monoxide;
- Infrared Spectra;
- Methyl Compounds;
- Molecular Excitation;
- Photodissociation;
- Vibrational Spectra;
- Emission Spectra;
- Laser Target Interactions;
- Molecular Rotation;
- Radicals;
- Rydberg Series;
- Atomic and Molecular Physics