Error analysis for complex kinetics systems methyl-vinyl cross-radical reactions

Many rate constants, particularly for radical-radical reactions, are determined in systems exhibiting complex kinetics. Parameters often comprise several species concentrations, absorption cross sections, and rate constants. They cannot be obtained from an exact analytic expression, and therefore, must be solved iteratively through an efficient numerical differential equation solver. We examine here the reaction kinetics of the CH₃ and the C₂H₃ mixed-radical system, generated by excimer laser photolysis of methyl vinyl ketone (MVK) at 193.3 nm. As a model, a detailed error analysis for determination of the cross-radical reaction rate constant, the initial CH₃ and C₂H₃ radical concentrations are performed using a least-squares modeling program (Acufit). The least-squares program, an assumed mechanism, a detailed set of signal-averaged data, are viewed as the measuring “instrument.” The output of the “instrument” consists of a “signal” that is fit to the data using the least-squares criterion. This gives estimated parameters that are examined with respect to random as well as systematic errors. The biases due to uncertainties of each known parameter and combined uncertainties on the measured parameters are assessed. © 1994 John Wiley & Sons, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.