Challenges for Density Functional Theory

Understanding current and future challenges for density functional theory (DFT) are focused. One of the main challenges for DFT is to keep as its cornerstone some element of simplicity. It also include the need to improve the description of reaction barriers and dispersion/van der waals interactions and understand the energy of two protons separated by infinity with one and two electrons. It is very difficult to determine an accurate form of the exchangecorrelation from first principles. A more practical approach is to take available experimental information to help determine and test the functional forms. It is important to address the particularly challenging problem of exchangecorrelation from other angles as well such as constructing approximate functionals and minimizing the total energy. The essence of self-interaction can be understood from the behavior of the energy of one electron.