The performance of range separated hybrid exchange functional, consisting in a mix of short range density functional exchange with long range Hartree-Fock exchange, is tested against formation enthalpies of molecules, ionization potentials of atoms and dissociation curves of 2-center 3-electron systems. The mixing of the two exchange components is governed by a single parameter, characterizing the reach of the density functional description. In addition to offering a solution to the problems related to the incorrect asymptotic behavior of exchange potentials derived from approximate density functionals, the range separated hybrid leads to quite good energetic results, even in a local density framework. (c) 2005 Elsevier B.V. All rights reserved.