Bond order conservation

The dependence on electron locahzation energy can also be illustrated by the use of the bond order conservation principle. This principle gives an approximate recipe to estimate changes in bond strength when coordination of a surface atom or adsorbate attachment changes [5, 15]. 

Shustorovich, E. (1990) The bond-order conservation approach to chemisorption and heterogeneous catalysis applications and implications, Adv. Catal. 37, 101. 

Analytical expressions for interactions can be regarded either as mathematical in origin or with a physical origin.The former have often a simple form and they hold for many if not all systems, but they may have many parameters. The latter are based on the mechanism that leads to the interactions, they have seldom a simple mathematical form, they generally hold only for a limited set of systems, but they may have only few parameters.An expansion in terms two-, three-, four-, and more-particle interactions (see Sections 3.2.1 and 3.2.2) is an example of a mathematical model for lateral interactions. As an example of a physical model we only present the bond-order-conservation model in Section 3.2.3 as this is the model that has been used most extensively in kMC simulations. 

Bond-Order-Conservation. Bond-order-conversation (BOC) is based on the observation that when an atom forms bonds with other atoms the energy gain is high for the first bond that is formed but then decreases with each subsequent bond. BOC is an attempt to quantify this observation. The bond order x in BOC is defined as the following function of the bond length R. 

The Bond-Order Conservation Approach to Chemisorption and Heterogeneous Catalysis Applications and Implications... 

Finally, one should mention that some version of bond-order conservation, known as the bond-energy/bond-order (BEBO) method, has been applied to chemisorption bonding and surface reactivity by Weinberg and... 

---