Exchange-correlation energy functional hybrid

A very popular functional, optimized to reproduce experimental atomization energies, is the "hybrid" exchange-correlation B3LYP functional (= Becke, three-parameter, Lee, Yang, and Parr) ... 

The underlying formalism and properties of these hybrid functionals has been reported by Gorling and Levy [78]. These schemes obtained part of the exchange correlation energy from the KS orbitals using a procedure identical to the one used in the HF procedure to obtain the exchange energy. 

Exc[p for molecules is such a functional of p that for a fixed p the value of Exc is equal to the known value f for the uniform electron gas corresponding to the same density 6. The DFT hybrid approximation Exc stands for the exchange-correlation energy) ... 

Hybrid potentials involve some combination of exact HF exchange mixed into the DFT-GGA potential, the most common being the B3LYP functional. The exchange-correlation energy is ... 

A variety of hybrid schemes combine Hartree-Fock exchange with density functional exchange and correlation (Becke 1993). These hybrid schemes may be empirical insofar as they result from fitting to thermochemical data. For example, the BY3LP exchange-correlation energy is... 

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