In cases of problematic open-shell references, e.g., strongly spin-contaminated doublet, triplet or quartet states, one may choose to use DFT orbitals. This can be achieved by first doing DFT calculation and then reading the orbitals and turning Hartree–Fock off (by setting SCF_GUESS = READ and MAX_SCF_CYCLES = 0 in the CCMAN or CCMAN2 job). In CCMAN, a more convenient way is just to specify EXCHANGE, e.g., if EXCHANGE = B3LYP, B3LYP orbitals will be computed and used. See Section 6.15 for additional discussion of alternative orbital choices in correlated wave function calculations.
Note: Using non-HF exchange in CCMAN2 is not possible.