shape and electric potential are the driving factor in this graphical approach. Molecular dynamics Application of classical mechanics for simulating the movement of the nuclei of an assembly of atoms and molecules. The rearrangement of molecules within an ensemble is controlled by Van der Waals forces and promoted by temperature. Molecular mechanics Modeling of the intra- and inter-molecular interaction potential energy surfaces via potentials. The latter are usually parameterized from ab initio calculations. Mathematical chemistry Discussion and prediction of the molecular structure using mathematical methods without necessarily referring to quantum mechanics. Topology is a branch of mathematics that allows researchers to predict properties of flexible finite size bodies like clusters. Theoretical chemical kinetics Theoretical study of the dynamical systems associated to reactive chemicals, the activated complex and their corresponding differential equations. Cheminformatics (also known as chemoinformatics) The use of computer and informational techniques, applied to crop information to solve problems in the field of chemistry.: Chemical engineering The application of chemistry to industrial processes to conduct research and development. This allows for development and improvement of new and existing products and manufacturing processes. Closely related disciplines Historically, the major field of application of theoretical chemistry has been in the following fields of research: Atomic physics: The discipline dealing with electrons and atomic nuclei. Molecular physics: The discipline of the electrons surrounding the molecular nuclei and of movement of the nuclei. This term usually refers to the study of molecules made of a few atoms in the gas phase. But some consider that molecular physics is also the study of bulk properties of chemicals in terms of molecules. Physical chemistry and chemical physics: Chemistry investigated via physical methods like laser techniques, scanning tunneling microscope, etc. The formal distinction between both fields is that physical chemistry is a branch of chemistry while chemical physics is a branch of physics. In practice this distinction is quite vague. Many-body theory: The discipline studying the effects which appear in systems with large number of constituents. It is based on quantum physics – mostly second quantization formalism – and quantum electrodynamics. Hence, theoretical chemistry has emerged as a branch of research. With the rise of the density functional theory and other methods like molecular mechanics, the range of application has been extended to chemical systems which are relevant to other fields of chemistry and physics, including biochemistry, condensed matter physics, nanotechnology or molecular biology. See also