Computational Chemistry Tools for Atomic Level Investigation of Clay Composites

The most common computational methods used for the investigation of molecular and periodic systems will be briefly described, with particular emphasis on those approaches that could be employed for the study of clay structures at the atomistic level. The first part of the chapter is mainly dedicated to the conceptual basis of density functional theory and its implementation for molecular and periodic systems. The tight binding approximation to density functional theory and its modern variants, particularly suitable for atomistic studies of large systems, is treated as well. Classical molecular mechanics and molecular dynamics methods, as well as the definition of force fields suitable for clay materials, are shortly discussed. In the second part, case studies of application of computational approaches for the characterization of structures and properties of clay materials (in particular, the halloysite nanotube) are reported.