Rectifying shortcomings of density-functional methods by the optimized effective potential approach

• Applicant: Professor Dr. Andreas Görling
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 578303930

The optimized effective potential (OEP) method is used to rectify long-standing fundamental shortcomings of density-functional methods based on the Kohn-Sham (KS) or generalized KS formalism. Gaussian-basis-set OEP methods have been plagued by numerical instabilities for a long time. This problem has recently been solved, which opens up the possibility to take advantage of the potential OEP methods offer. By combining the OEP approach with established standard exchange-correlation functionals the problem of qualitatively wrong KS orbital and eigenvalues spectra will be solved. For open-shell systems, symmetry breaking in spin and real space leading, amongst others, to spin contamination can be avoided by employing the OEP approach to implement methods within a symmetrized KS formalism, which, so far, could not be applied in practice. Using the resulting orbitals and eigenvalues in time-dependent density-functional approaches increases the accuracy of the latter and makes it possible to properly take into account all symmetries. Recently developed σ-functional methods represent the presently most accurate KS methods even though they are currently still applied in a post-SCF (post-Self Consistent-Field) manner. With the help of the OEP approach self-consistent σ-functional methods shall be developed in the framework of the symmetrized KS formalism. With such methods the long-standing goal of highly accurate, generally applicable KS methods free of any symmetry breaking shall be reached.

• DFG Programme: Research Grants