Published online by Cambridge University Press: 10 February 2011
Many reactions of interest occur in the solid state, or with low mobility of the reactants or products, with the result that the physical mechanisms operative during the reaction determine the shape of the reaction rate-time profile; i.e. topochemistry is important. However, often improper account is taken of the physical mechanisms, resulting in erroneous values for the activation energy and kinetic constants.
An improved method of analysis is suggested, allowing the mechanisms of reaction to be determined explicitly. This thus allows the activation energy and kinetic constants to be determined with good theoretical justification. The method has been verified by studying the thermal decomposition of barium azide, where the activation energy was determined to better than 1%. The operative mechanisms so determined are in agreement with visual observations and the literature.