Showing papers by "William P. L. Carter published in 1996"

Development and evaluation of a detailed mechanism for the atmospheric reactions of isoprene and NOx

Abstract: A detailed photochemical mechanism for the atmospheric reactions of isoprene and its major oxidation products in the presence of NOx, which incorporates the most recent laboratory results and our current understanding of the system, is described. It is evaluated by comparing its predictions against results of NOx-air irradiations of isoprene and its two major products, methacrolein, and methyl vinyl ketone (MVK), in five different types of environmental chambers at two different laboratories. In most cases it simulated experimental results within the uncertainty of the data and the chamber and run characterization model. However, the photodecomposition quantum yields of methacrolein and MVK and the organic nitrate yield from the OH + isoprene reaction had to be adjusted to obtain satisfactory simulations of the data. The major discrepancy observed was that the model tended to underpredict PAN by ca. 40% in the isoprene experiments, despite the fact that the model predicted PAN from methacrolein and MVK reasonably well. The uncertainties and additional data needed to completely characterize the isoprene atmospheric photooxidation system are discussed. © 1996 John Wiley & Sons, Inc.

Rate constants for the reactions of o(3p) with selected monoterpenes

Abstract: Rate constants for the gas phase reactions of O( P) atom with a series of monoterpenes have been determined at ambient temperature (~302-309K) and atmospheric pressure using a relative rate technique. Using the literature rate constants for O( P) + isobutene, cisand trans -2-butene, 3-methyl-1-butene, 2-methyl-2-butene and 2,3-dimethyl-2-butene as the standards, the O( P) rate constants derived for the terpenes (in units of 10 -11 cmmolecules) are 2.8±0.4 forα-pinene, 2.8±0.5 forβ-pinene, 3.1±0.5 for ∆-carene, 3.5±0.5 for 2-carene, 2.6±0.5 for camphene, 7.6±1.2 for d-limonene, 9.0±1.6 for γ-terpinene and 10.7±1.6 for terpinolene. The relative rate constants in this work agreed with literature values to within ±10% for the standard alkenes, and to within ±~35% for the terpenes. Compound Index: O( P), α-pinene,β-pinene,∆-carene, 2-carene, camphene, d-limonene, γ-t rpinene, terpinolene, 2-methyl-2-butene, isobutene, cis-2-butene, trans-2-butene, 3-methyl-1-butene, 2,3-dimethyl2-butene Subject Index: O( P) rate constants, monoterpenes