Crystallization from solution is an important separation and purification process used in a wide variety of industries. In addition to product purity, it is often necessary to control the external shape and size of the crystals and to produce the desired polymorph and/or optical isomer. In some applications it is necessary to inhibit the formation of crystals or control their size and shape by the use of an additive.

Molecular modeling or calculational chemistry are terms that are used to describe techniques that employ quantum mechanics and statistical mechanics in conjunction with computer simulation to study the chemical and physical properties of materials.

In recent years, molecular modeling has emerged as a useful tool in the solution of a number of the crystallization problems mentioned above. In particular, modeling allows more focused experimentation based on structural and energetic calculations instead of intuition and trial and error. The availability of commercial modeling packages has led to its widespread use in many industrial and academic laboratories. These packages often lead to investigators treating the modeling process as a “black box” without understanding the basic principles underlying the methods. The purpose of this book is to explain the basic concepts of molecular modeling and their application to problems in crystallization.

The first two chapters introduce basic molecular modeling concepts (Chapter 1) and the basics of crystals and crystallization (Chapter 2).