In the expression of best identified model describing the olefin yield = ?:#$â< ()((* (eq. 5, Table ), the specific surface area of the activated catalyst (s 9BC ), the surface RAE content of the activated catalyst under UHV (L M,9BC OPQ ), the surface RAE oxidation states on the spent catalyst under UHV (c M,M>C OPQ ), and the surface RAE oxidation states under dry feed (c M,@"J OPQ )