What are the limitations of DFT in quantum chemistry?

What are the limitations of DFT in quantum chemistry?

Density Functional Theory (DFT) has several limitations, including its reliance on approximations for exchange-correlation energy, which can lead to inaccuracies in predicting molecular properties.

Can you explain why the exchange-correlation functional is important?

The exchange-correlation functional is crucial because it accounts for the interactions between electrons. An accurate functional is essential for reliable results in DFT calculations.

Are there specific systems where DFT fails?

Yes, DFT often struggles with systems involving strong electron correlation, such as transition metal complexes and certain excited states.

What alternatives to DFT exist?

Alternatives include wave function methods like Hartree-Fock, post-Hartree-Fock methods, and other quantum chemistry approaches that can provide more accurate results for challenging systems.

How can I improve the accuracy of DFT calculations?

You can improve DFT accuracy by using hybrid functionals, increasing the basis set size, or employing methods like DFT+U for systems with strong correlations.