Simplified Representations of KBC

Let us consider some simplified forms of KBC (14.1.3) with the kernel defined by (14.1.4). 

As pointed out earlier, one can simplify expression (14.1.4) substituting functions 9c fc with equilibrium ones fcO along with the change / fc/o- This way of KBC linearization is valid provided the deviations of functions ge, fc from their equilibrium values are small. If it is not the case, one has to take into account the terms, arising from the expansion of the kernel K c over the small parameter. It is generally thought that for lineaiized KBC Kc c meets microscopic detailed balance principle. 

Detailed probabilities Pc o. b, b), Pc co(b, b), dco b) are assumed to be calculated on the base of dynanrical modek, while average integral probabilities of adsorption, direct nonreactive and reactive desorption - on the base of thermodynamical and phenomenological approaches together with experimental data. For example, the eulsorption probability may be presented as a sum of the probabilities related to reactive (r) and nonreactive (n) adsorption channek 

The total reactive desorption probability may also be presented as a sum of the probabilities connected with different mechanisms (LH - Langmuir-Hinshelwood, D - direct)  

This expression is a generalization of a widely used Maxwell scattering kernel that takes into account realistic inelastic scattering Pc b, b), desorption dco b) and adsorption aco- 

---