A field which employs computers to model and study chemical systems and chemical behavior, using various models, from approximations of the Schrödinger equation to Monte-Carlo simulations, to modeling with differential equations.

A branch of chemistry which uses computer simulations to assist in solving chemical problems by modeling and studying chemical systems, and chemical behaviour.

It uses various methods from theoretical chemistry (from approximations of the Schrödinger equation to Monte-Carlo simulations to modeling with differential equations), incorporated into efficient computer programs, to calculate the structures and properties of molecules and solids. It is necessary because the quantum many-body problem cannot be solved analytically, much less in closed form.

While computational results normally complement the information obtained by chemical experiments, it can in some cases predict hitherto unobserved chemical phenomena. It is thus widely used in the design of new drugs and materials.