Density functional theory

Density functional theory (DFT) is a theory of electronic structure that is written in terms of the electron density distribution. This contrasts with traditional methods in quantum mechanics which are based on the more complicated many-electron wavefunction.

Table of contents

1 Description of the Theory 2 Early Models 3 Kohn-Sham Theory 3.1 Approximating Exchange and Correlation 4 References

Description of the Theory

Modern DFT is in principle an exact theory, though in practice approximations have to be made to important quantities. DFT therefore sacrifices some of the accuracy of traditional methods in return for a greatly reduced computational cost.

DFT has been very popular for calculations in solid state physics since the 1970s. However, it was not considered accurate enough for calculations in quantum chemistry until the 1990s, when the approximations used in the theory were greatly refined. DFT is now the leading method for electronic structure calculations in both fields.

Early Models

The first true density functional theory was developed by Thomas and Fermi in the 1920's.

Kohn-Sham Theory

Approximating Exchange and Correlation

References

[1] P. Hohenberg and W. Kohn, Phys. Rev. 136 (1964) B864.
[2] W. Kohn and L. J. Sham, Phys. Rev. 140 (1965) A1133.\n