Meta-GGA and hybrid functionals are established functionals that depend on the occupied orbitals. Correlation functionals based on the adiabatic-connection fluctuation-dissipation theorem 100,101 depend on unoccupied as well as occupied orbitals and their eigenvalues. The simplest example of such a functional is the correlation energy within the random-phase approximation (RPA). All these methods are Kohn-Sham methods or, depending on the way the exchange-correlation potential is obtained, generalized Kohn-Sham methods.