Abstract

A modification in the parameter fitting of an hybrid functional yields a new functional which is able to improve the atomic highest orbital energy. According to the Janak?s theorem it should be equal to the ionization potential. Results for the atoms hydrogen to argon confirms the improvement. The dipole polarizabilities are also improved. We discuss and show that such a modification can not be applied to molecular systems. Further, it is shown that long range interactions can be also improved. As an example, the classical transition barrier of the H + H2 H2 + H reaction has been calculated