title: Product study of the reaction of CH3 with OH radicals at low pressures and temperatures of 300 and 612 K.
abstract: The product distribution for the title reaction was studied using our time-of-flight mass spectrometer (TOFMS) connected to a tubular flow reactor. The methyl and hydroxyl radicals were produced by an excimer laser pulse (lambda = 193 nm) photolyzing acetone and nitrous oxide in the presence of excess water or hydrogen. Helium was used as the bath gas; the total density was held constant at 1.2 x 10(17) cm(-3). At 300 K the observations were consistent with singlet methylene ((1)CH(2)) and water as the main product channel with a small contribution of methanol. In contrast, at about 610 K three channels-formaldehyde isomers and methanol in addition to (1)CH(2) + H(2)O-are formed with similar yields. When acetone-d(6) was used, the production of both CHDO and CD(2)O was observed, indicating that two different formaldehyde-producing channels are operating simultaneously. These experimental results are compared with RRKM and master equation calculations on the basis of the properties of the methanol potential energy surface from a recent ab initio study.
authors.affiliation: Chemistry Department 555A, Brookhaven National Laboratory, P. O. Box 5000, Upton, New York 11973-5000, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Fockenberg
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Weston
authors.forename: James T
authors.initials: JT
authors.lastname: Muckerman