Theoretical and experimental investigation of the dynamics of theproduction of CO from the CH3 + O and CD3 + O reactions

Journal Article · Wed Mar 14 04:00:00 EST 2001 · Journal of Physical Chemistry A

DOI:https://doi.org/10.1021/jp010961f· OSTI ID:928319

Marcy, Timothy P; Diaz, Robert Richard; Heard, Dwayne; Leone, Stephen R; Harding, Lawrence B; Klippenstein, Stephen J

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: COLLABORATION - U.Colorado
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 928319
• Report Number(s): LBNL--52072; BnR: KC0301020
• Journal Information: Journal of Physical Chemistry A, Journal Name: Journal of Physical Chemistry A Journal Issue: 36 Vol. 105
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BRANCHING RATIO
CLEAVAGE
DEUTERATION
METHOXY RADICALS
METHYL RADICALS
PRODUCTION
TEMPERATURE DEPENDENCE
TRAJECTORIES