Reactivity, static indices

Carbon monoxide chemisorption was used to estimate the surface area of metallic iron after reduction. The quantity of CO chemisorbed was determined [6J by taking the difference between the volumes adsorbed in two isotherms at 195 K where there had been an intervening evacuation for at least 30 min to remove the physical adsorption. Whilst aware of its arbitrariness, we have followed earlier workers [6,10,11] in assuming a stoichiometry of Fe CO = 2.1 to estimate and compare the surface areas of metallic iron in our catalysts. As a second index for this comparison we used reactive N2O adsorption, N20(g) N2(g) + O(ads), the method widely applied for supported copper [12]. However, in view of the greater reactivity of iron, measurements were made at ambient temperature and p = 20 Torr, using a static system. 

The static quantum chemical indexes of the reactivity may be used for description of kinetics of double exchange reactions which occur through the transition state with high charges separation [17. If a barrier height of the surface reaction is controlled by frontier orbitals interaction, then the following correlation may be fulfilled ... 

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