Reaction kinetics in acetyl chemistry over a wide range of temperature and pressure

Abstract

The molecular modulation spectrometer has been used to study the complex chemical kinetics involved in acetyl radical chemistry. This has involved direct monitoring of both acetyl and methyl radicals in the same experiment and over a variety of temperatures (263 ⩽T/K ⩽ 343) and total gas concentration (0.3 ⩽[M]/10¹⁹ molecule cm^–3⩽ 2.7) conditions. These measurements have been complemented by a non-linear least-squares analysis of the experimental data and simple product studies. Rate data on four reactions and the absorption cross-section of the acetyl radical at 223 nm have been determined in this way. Unimolecular rate theory, based on Kassel integrals, has been applied to the pressure-dependent formation and decay of the radical to extract limiting values for the rate constants at T= 303 and 343 K.