Computer Modeling of Zeolites

The structure and chemical composition of zeolites and related microporous solids (such as aluminophosphates) give rise to a wide variety of physicochemical properties, many of which are exploited commercially. Their open framework structure, containing pores, channels, and cavities, results in molecular sieving properties; only molecules of suitable dimensions can enter and diffuse through the solid. Extra-framework metal cations are exchangeable, leading to commercial use as water softeners in detergents. In their proton-exchanged form, zeolites are strong solid (Brønsted) acids, which, coupled with their porous nature, make such materials size- and shape-selective catalysts.
Although a range of experimental techniques are widely and successfully applied to the study of the structure and reactivity of microporous solids, computational methods have grown in prominence since the early 1980s. They are increasingly seen as an essential complement to experiment, but also as ‘experimental’ techniques in their own right. A number of reviews are available (Catlow, 1997; Catlow et al., 1997, 1999; Bates and van Santen, 1998; Van de Graaf et al., 2000). Indeed, the field of microporous solids sees a large variety of computational methods applied over many length scales to study a broad range of physical phenomena.
The complexity of the models and the methods used are determined by the problem to be investigated. Some of the computational techniques, together with some salient examples of their use are presented in this article.