RATE-CONSTANT AND A DETAILED ERROR ANALYSIS FOR C2H3+H REACTION

The production and reactions of vinyl radicals and hydrogen atoms from the photolysis of vinyl iodide (C2H3I) at 193 nm have been examined employing laser photolysis coupled to kinetic-absorption spectroscopic and gas chromatographic product analysis techniques. The time history of vinyl radicals in the presence of hydrogen atoms was monitored using the 1,3-butadiene (the vinyl radical combination product) absorption at 210 nm. By employing kinetic modeling procedures a rate constant of 1.8 x 10(-10) cm(2) molecule(-1) s(-1) for the reaction C2H3 + H has been determined at 298 K and 27 KPa (200 torr) pressure. A detailed error analysis for determination of the C2H3 + H reaction rate constant, the initial C2H3 and H concentrations are performed. A combined uncertainty of +/-0.43 x 10-10 cm(2) molecule(-2) s(-1) for the above measured rate constant has been evaluated by combining the contribution of the random errors and the systematic errors (biases) due to uncertainties of each known parameter used in the modeling. (C) 1995 John Wiley and Sons, Inc.