Based on the variational principle, one might expect that the ground state energy of a density functional theory (DFT) calculation will decrease as the basis set size increases. (As I understand it, this is the case in Hartree-Fock.)Mathematically speaking, is it in fact true that the DFT energy decreases with basis set size? If so how would you prove it? It seems like the variational principle might not directly apply since DFT, unlike Hartree-Fock, does not explicitly construct a many-body wavefunction.
Does energy decrease with basis set size in density functional theory?
computational chemistry;convergence;basis set;density functional theory