Recurrent generation of approximate functionals in density functional theory *

The idea of recurrent generation of approximate exchange–correlation energy density functionals in density functional theory is investigated and evaluated in this article through the so‐called Levy transformation, which enables one to obtain the exact exchange correlation energy without knowing the details of its kinetic energy component. Although in principle the transformation is valid only for exact functionals, it is argued that approximate functionals may also be applied and then recurrently used. As a demonstration of the idea, a generalized form of the Wigner‐type functional is introduced and transformed into polylogarithm functionals. Numerical illustrations of examples show that for local functionals, better results may be yielded after the transformation, whereas for nonlocal functionals, identical results have been obtained for n ≥2 transformations. In addition, two nonlocal approximate functionals beyond the generalized gradient approximation (GGA) are proposed which show better performance in energetics over GGA functionals. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002