For Kohn-Sham calculations, compute exchange energy according to Hartree-Fock formalism and add the contribution scaled by factor to the fock matrix and the energy functional. Otherwise, the default is factor=0, i.e., the exchange is assumed to be contained in the functional, and only the Coulomb interaction is calculated explicitly.
DFTFACTOR,fac1, fac2, ...
Provide a factor for each functional specified. The functionals will be combined accordingly. By default, all factors are one.