chapter  51
6 Pages

Two-site processes

The influence of the interaction of neighbouring particles is manifested primarily in the fact that, depending on the local composition of neighbours around the central pair ij, the height of the activation barrier of the elementary reaction between reagents i and j varies. The number of the nearest neighbours around the central pair ij will be denoted by z*. We will characterize the arrangement of the neighbouring particles A around the reagents ij by the symbols n and σ, where n is the number of particles A in the first coordination sphere z* around the pair of particles ij (respectively, (z*–n) of sites is occupied by vacancies); σ(n) is the index that determines the way the particles are arranged for a fixed n (Fig. 51.1).