We report the extension of our Slater-type orbital (STO) basis code for density functional theory (DFT) calculations to include "exact exchange," so that Hartree-Fock and hybrid DFT calculations may be performed. Exchange integrals are evaluated through the insertion of a resolution of the identity, using the same auxiliary STO basis set which was used in our original generalized gradient approximation DFT studies. Three-center two-electron integrals are evaluated by quadrature. A scheme for introducing diatomic auxiliary STO basis sets is introduced, which enables much larger calculations to be performed. We also report an extension to the evaluation of second-order molecular properties using these functionals. Calculations for excitation energies to valence and Rydberg states are included. (C) 2003 American Institute of Physics.