  We present an implementation of range separated functionals utilizing the
Slater-function on grids in real space in the projector augmented waves method.
The screened Poisson equation is solved to evaluate the necessary screened
exchange integrals on Cartesian grids. The implementation is verified against
existing literature and applied to the description of charge transfer
excitations. We find very slow convergence for calculations within linear
response time-dependent density functional theory and unoccupied orbitals of
the canonical Fock operator. Convergence can be severely improved by using
Huzinaga's virtual orbitals instead. This combination furthermore enables an
accurate determination of long-range charge transfer excitations by means of
ground-state calculations.
