where c HF and c MRSF denote the coefficients for the exact Hartree-Fock exchange used in SCF and response calculations, respectively. The h pqσ and (pq|ii) are the one-and two-electron integrals, respectively, and V xc pqσ represents the matrix elements of the first functional derivatives of the XC functional with respect to electron density. All two-electron integrals are written in chemist notation. We have generally assumed that c MRSF is equal to c HF .