Optimizing Complex Kinetics Experiments Using Least-Squares Methods

Complex kinetic problems are generally modeled employing numerical integration routines. Our kinetics modeling program, Acuchem, has been modified to fit rate constants and absorption coefficients generically to real or synthesized "laboratory data" via a least-squares iterative procedure written for personal computers. To test the model and method of analysis the self- and cross-combination reactions of HO2 and CH3O2 radicals of importance in atmospheric chemistry are examined. These radicals as well as other species absorb ultraviolet radiation. The resultant absorption signal is measured in the laboratory and compared with a modeled signal to obtain the best-fit to various kinetic parameters. The modified program generates synthetic data with added random noise. An analysis of the synthetic data leads to an optimization of the experimental design and best-values for certain rate constants and absorption coefficients.