Quasi-Steady State Conditions and Reaction Routes

QUASI-STEADY STATE CONDITIONS AND REACTION ROUTES 

According to the QSS approximation, the rates of formation and consumption of the surface intermediates are approximately equal, so that the time derivatives of the coverages of the intermediates may be set equal to zero 

(14) and (15) may be referred to as the conventional formulation of the QSS approximation conditions. The QSS conditions may be expressed in a more useful form by employing the theory of RRs. Consider an arbitrary set of I linearly independent RRs 

According to the Horiuti-Temkin theorem [9,10], the number of linearly independent RRs is equal to I = p - ranka = p - q. Now, let Ju Ji be the corresponding rates (or, the RR fluxes) along the arbitrarily selected set of linearly independent RRs, namely RRu RR2. RRi. Then, within the QSS approximation the following relation between RR fluxes and the rates of individual elementary reaction steps is valid 

A particular set of / linearly independent RRs may always be selected from the list of enumerated direct RRs as follows. Because the rank of the intermediate matrix a is equal to q, at least one determinant of order 9 in a is different from zero. Without loss of generality, we assume that 

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