A computational method that calculates electronic structure from electron density.
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Density functional theory is a quantum mechanical method in which the total energy of a system is expressed as a functional of the electron density rather than of the full many-electron wavefunction. This reduces the computational cost dramatically, because the electron density depends on only three spatial coordinates, while the wavefunction depends on three coordinates for every electron. The exact exchange-correlation term is unknown, so approximate functionals such as the widely used B3LYP hybrid are employed, and their accuracy varies with the property studied. DFT is applied to molecules, solids and surfaces and is one of the most widely used methods in modern chemistry. Results depend on the functional and basis set chosen.
Key ideas: Hohenberg-Kohn theorems say the ground-state density determines all properties. In practice Kohn-Sham equations are solved self-consistently with exchange-correlation functionals: LDA, GGA (PBE), hybrids (B3LYP, PBE0) and range-separated types. Dispersion corrections (such as D3) are needed for weak interactions. Chemical accuracy means about 4 kJ/mol, which DFT often misses for reaction barriers and charge transfer.
Common mistakes and connections: Students think DFT is exact because the theorems are exact, but approximate functionals introduce errors. Standard functionals fail for van der Waals forces, strongly correlated systems and band gaps. Choosing the functional by popularity rather than benchmarks is risky. Basis set quality also affects results. Related to Hartree-Fock, electron correlation and molecular orbital theory.
DFT works with electron density, which depends on only three spatial coordinates; here is the radial density of a hydrogen-like 1s electron. The interactive lesson shows this as a live animation or chart.
B3LYP with a suitable basis set is a common choice for optimizing the geometry of an organic molecule.
A computational method that calculates electronic structure from electron density.
Density Functional Theory is a advanced topic in Analytical, Lab & Spectroscopy. It builds on beginner and intermediate topics, so review those first if needed.
Study these earlier topics in Analytical, Lab & Spectroscopy first: Thermogravimetric Analysis, Differential Scanning Calorimetry, Computational Chemistry.
The next topics in Analytical, Lab & Spectroscopy are Molecular Dynamics and Hartree-Fock Method.
Yes. The interactive lesson includes a self-check question on Density Functional Theory, and the Analytical, Lab & Spectroscopy quiz draws on every topic in this area.
Density Functional Theory is topic 84 of 99 in Analytical, Lab & Spectroscopy.