Quantum chemistry

• What Is the Exchange-Correlation Hole in DFT?
  The exchange-correlation hole describes how exchange and electron interactions change the density around a reference electron, and how that change enters DFT.
• Can Traditional DFT Calculate Excited-State Properties?
  Ground-state DFT alone does not generally predict excitation energies; learn when to use TD-DFT or ΔSCF and which excited-state properties they provide.