Computational Techniques (DFT,MM,TD‐DFT,PCM)

Abstract Computational techniques can be used to simulate molecular and atomic behavior based on fundamental descriptions of atomic and molecular orbitals ( ab initio quantum mechanics), experimental data ( a priori molecular mechanics), or a combination of both (semiempirical methods). The choice of method depends on the task in hand and the computational resources available. Low‐level molecular mechanics, molecular dynamics, conformational analysis, and periodic boundary simulations are described along with quantum mechanical approaches (Hartree‐Fock, density functional theory, and other post‐Hartree‐Fock methods) and intermediate semiempirical methods. Keys to the success of any computational method are the adoption of an appropriate model and the methods used to generate that model. By constructing models that reflect both the correct structures of the complex and its components together with changes in experimental parameters, supramolecular phenomena, such as host–guest binding, can be studied in detail using theoretical models. Applications of these methods in the field of supramolecular chemistry are illustrated with examples drawn from crown ether, cyclodextrin, and calixarene complexes.