Computational chemistry, a.k.a. theoretical chemistry or molecular modelling, uses computer simulations of molecular structures to investigate the structures, properties and reactions of molecules.
There are many different approaches to computational chemistry, ranging from very simple models (in essence treating atoms as hard spheres and bonds as springs), great when a large number of atoms or related structures need to be considered, to very sophisticated attempts at reporducing the electronic structure, which are often limited to small systems only because they are so demanding of computer resources.
Computational studies can support and enhance chemistry in may ways, from helping to analyse spectra obtained via a range of techniques (IR, NMR, UV/Vis, EPR etc.), to interpreting experimental results, such as unexpected results for a chemical reaction. They can be used to test whether a hypothesis about the reaction pathway taken is likely, and, if things go well, they can be applied to novel, toxic and unknown molecules and reactions, in the ideal offering an approach to making predictions before any synthesis is attempted.
Compiled by Lucy Bird and Natalie Fey.