Formal Chemisorption Theory

The theoretical chemical application of surface chemical bonding theory, highlighted next, is related to formal chemisorption theory as developed in surface physics, but concentrates on quantum chemical concepts as the electron distribution over bonding and antibonding orbital fragments [5, 6]. It will be seen that both approaches complement each other. The notion of a surface molecule relates to the surface physicists concept of surface state. 

A number of valuable conceptual ideas were bom out of Formal Chemisorption Theory. Most of which are now well understood, and have been used to explain the results from quantum chemical analyses of chemisorption on a number of transition metal surfaces. Formal theory, for example, has been used to identify a series of general trends and concepts relevant to the understanding adsorption phenomena on metal surfaces [2]. These include the following ideas ... 

Formal chemisorption theory has also been used to described a number of other important chemisorption phenomena, such as the stabilizing effects of neighboring electropositive adsorbates (K, Na), the destabilizing effects of electronegative adsorbates (Cl, F), surface relaxation and surface reconstruction [18], More recently. Hammer and Nbrskov [17] applied formal theory to elegantly explain the results from a series of large-scale periodic density functional quantum chemical calculations for adsorption on transition metal and bimetallic surfaces. Chemisorption theory will undoubtedly continue to play an important role in describing relevant concepts in chemisorption and surface reactivity well into the future. More quantitative results from theory, however, will require more sophisticated quantum mechanical methods. 

Based on the previous assumptions, we can rigorously and explicitly determine an analytical expression of the apparent kinetic constants, between all the lumped families (Fx -> Fy) according to intrinsic elementary kinetic constants as specified in the Single-Events theory (Cochegrue, 2001 Schweitzer, 1998 Valery, 2002). The same applies for the denominator DEN (see next Fig. 26), in which the sum of the terms expresses the competitive chemisorption of all secondary and tertiary carbocations on the acid sites. The apparent kinetics so obtained formally return Langmuir-Hinshelwood expressions, traditional... 

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