The Use of a Stepwise Function

Since the total surface has been divided into equal elements of area, each being uniform, they contain the same number of adsorption sites. It is of interest to inquire as to the magnitude of the difference of activation energy between patches such that 99% of the sites of lower activation energy E .i are occupied while 99% sites of the next higher activation energy E are still bare, so that a condition assumed in the integration of Eq. (11) is satisfied. It is necessary that 

SO that, at 25°C, E — E i—B kcal/mole. Thus, for a surface comprising, say, 10 elements of area, the energy range, 30 kcal/mole, is quite large, and a rigorous solution of the rate equation would require summation in place of integration. 

---