Computational chemistry
Definition and meaning of Computational chemistry in chemistry.
Computational chemistry uses computer-based mathematical models and numerical algorithms to calculate the structures, properties, and reactivity of atoms and molecules. It applies the principles of theoretical chemistry, especially quantum mechanics, to systems too complex to solve exactly by hand.
In more detail
Because the Schrödinger equation can be solved exactly only for very simple systems (such as the hydrogen atom), computational chemists use approximate methods, ranging from high-accuracy ab initio and density functional theory (DFT) calculations to faster but less rigorous molecular mechanics and semi-empirical methods. Choosing a method involves a trade-off between accuracy and computational cost, which grows rapidly with the number of electrons or atoms. These calculations predict molecular geometry, energies, spectra, and reaction pathways, guiding and interpreting experimental chemistry, drug design, and materials discovery.
Key facts
| Field | Physical Chemistry |
|---|---|
| Core methods | Ab initio (e.g., Hartree-Fock), density functional theory (DFT), molecular mechanics |
| Theoretical basis | Approximate solutions to the Schrödinger equation |
| Common applications | Reaction mechanisms, spectroscopy prediction, drug and materials design |
A chemist uses density functional theory to optimize the geometry of a water molecule, calculating a predicted bond angle near 104.5 degrees and O-H bond length near 96 picometers, then compares these values to experimental microwave spectroscopy data to validate the method.
Frequently asked questions
How is computational chemistry different from theoretical chemistry?
Theoretical chemistry develops the underlying mathematical models and equations describing molecular behavior; computational chemistry implements and solves those models numerically using computers to generate quantitative predictions for specific molecules.
Can computational chemistry replace laboratory experiments?
No. Computational predictions are approximations that are typically validated against experimental data; they are used to interpret, guide, and extend experimental work rather than replace it.