Heterogeneous reaction at the interface between a solid surface and adjacent gas is central to many chemical processes such as chemical vapor deposition, chemical etching, combustion of solids, and catalytic processes. The KINetics software provides a powerful capability to help model, understand, and optimize important industrial and research chemical processes. The software is based on a systematic convention to translate heterogeneous reaction ideas into a form that is amenable to efficient computation.

The first part of this section is a discussion of how to formulate a surface reaction mechanism. This is followed by a compendium of some important equations in heterogeneous chemical kinetics. Many of the equations are simply definitions. Then we discuss how to set up the required symbolic input to define a surface reaction mechanism. We have allowed the possibility of including multiple site types, multiple mixtures of bulk species, and multiple materials. Each site type and bulk mixture may contain several species. Therefore, the data structures needed to refer to the phases and the species can be complex.