Theoretical and experimental investigation of the dynamics of the production of CO from the CH{sub 3} + O and CD{sub 3} + O reactions.

Journal Article · Thu Sep 13 04:00:00 EDT 2001 · J. Phys. Chem. A

DOI:https://doi.org/10.1021/jp010961f· OSTI ID:953404

Marcy, T P; Diaz, R R; Heard, D; Leone, S R; Harding, L B; Klippenstein, S J; NIST,; SNL,

Combined experimental and theoretical investigations of the title reactions are presented. Time-resolved Fourier transform infrared (FTIR) emission studies of CO (v = 1) produced from the CH{sub 3} + O and CD{sub 3} + O reactions show that there is approximately a one-third reduction in the branching to the CO channel upon deuteration of the methyl radical. Direct dynamics, classical trajectory calculations using a B3LYP potential surface, confirm the existence of the CO producing channel. The calculations show that the CO comes from the decomposition of HCO produced by the elimination of H{sub 2} from highly vibrationally excited methoxy radicals. Scans of the potential surface reveal no saddle point for the direct elimination of H{sub 2} from methoxy. The minimum-energy path for this elimination is a stepwise process involving first a CH bond cleavage, forming H + H{sub 2}CO, followed by an abstraction, forming H{sub 2} + HCO. However, at the high internal energies produced in the initial O + CH{sub 3} addition, trajectories for the direct elimination of H{sub 2} from methoxy are observed. The predicted branching ratio between the CO and H{sub 2}CO channels is in good agreement with previous room-temperature measurements, and there is predicted to be little temperature dependence to it. The observed reduction in the branching to the CO channel upon deuteration is also well reproduced in the calculations.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; OUS
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 953404
• Report Number(s): ANL/CHM/JA-38956
• Journal Information: J. Phys. Chem. A, Journal Name: J. Phys. Chem. A Journal Issue: 36 ; Sep. 13, 2001 Vol. 105; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CARBON MONOXIDE
CHEMICAL REACTION KINETICS
DECOMPOSITION
DEUTERIUM COMPOUNDS
METHOXY RADICALS
METHYL RADICALS
OXIDATION
SYNTHESIS